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* * * * *
THE VARIATION
OF
ANIMALS AND PLANTS
UNDER DOMESTICATION.
BY CHARLES DARWIN, M.A., F.R.S., &c.
IN TWO VOLUMES.--VOL. I.
WITH ILLUSTRATIONS.
LONDON:
JOHN MURRAY, ALBEMARLE STREET.
1868.
_The right of Translation is reserved._
* * * * *
BY THE SAME AUTHOR.
* * * * *
ON THE ORIGIN OF SPECIES BY MEANS OF NATURAL SELECTION; or The PRESERVATION
of FAVOURED RACES in the STRUGGLE for LIFE. Fourth Edition (_Eighth
Thousand_), with Additions and Corrections. 1866. ... MURRAY.
A NATURALIST'S VOYAGE ROUND THE WORLD; or, A JOURNAL OF RESEARCHES into the
NATURAL HISTORY and GEOLOGY of the COUNTRIES visited during the Voyage of
H.M.S. Beagle, under the Command of Capt. FITZ-ROY, R.N. _Tenth Thousand_.
... MURRAY.
ON THE STRUCTURE AND DISTRIBUTION OF CORAL REEFS. ... SMITH, ELDER, & Co.
GEOLOGICAL OBSERVATIONS ON VOLCANIC ISLANDS. ... SMITH, ELDER, & Co.
GEOLOGICAL OBSERVATIONS ON SOUTH AMERICA. ... SMITH, ELDER, & Co.
A MONOGRAPH OF THE CIRRIPEDIA. With numerous Illustrations. 2 vols. 8vo.
... HARDWICKE.
ON THE VARIOUS CONTRIVANCES BY WHICH BRITISH AND FOREIGN ORCHIDS ARE
FERTILISED BY INSECTS; and on the GOOD EFFECTS of CROSSING. With numerous
Woodcuts. ... MURRAY.
ON THE MOVEMENTS and HABITS of CLIMBING PLANTS. With Woodcuts. ... WILLIAMS
& NORGATE.
* * * * *
LONDON: PRINTED BY WILLIAM CLOWES AND SONS, STAMFORD STREET, AND CHARING
CROSS.
* * * * *
{iii}
CONTENTS OF VOLUME I.
INTRODUCTION ... Page 1
CHAPTER I.
DOMESTIC DOGS AND CATS.
ANCIENT VARIETIES OF THE DOG--RESEMBLANCE OF DOMESTIC DOGS IN VARIOUS
COUNTRIES TO NATIVE CANINE SPECIES--ANIMALS NOT ACQUAINTED WITH MAN AT
FIRST FEARLESS--DOGS RESEMBLING WOLVES AND JACKALS--HABIT OF BARKING
ACQUIRED AND LOST--FERAL DOGS--TAN-COLOURED EYE-SPOTS--PERIOD OF
GESTATION--OFFENSIVE ODOUR--FERTILITY OF THE RACES WHEN
CROSSED--DIFFERENCES IN THE SEVERAL RACES IN PART DUE TO DESCENT FROM
DISTINCT SPECIES--DIFFERENCES IN THE SKULL AND TEETH--DIFFERENCES IN THE
BODY, IN CONSTITUTION--FEW IMPORTANT DIFFERENCES HAVE BEEN FIXED BY
SELECTION--DIRECT ACTION OF CLIMATE--WATER-DOGS WITH PALMATED FEET--HISTORY
OF THE CHANGES WHICH CERTAIN ENGLISH RACES OF THE DOG HAVE GRADUALLY
UNDERGONE THROUGH SELECTION--EXTINCTION OF THE LESS IMPROVED SUB-BREEDS.
CATS, CROSSED WITH SEVERAL SPECIES--DIFFERENT BREEDS FOUND ONLY IN
SEPARATED COUNTRIES--DIRECT EFFECTS OF THE CONDITIONS OF LIFE--FERAL
CATS--INDIVIDUAL VARIABILITY ... Page 15
CHAPTER II.
HORSES AND ASSES.
HORSE.--DIFFERENCES IN THE BREEDS--INDIVIDUAL VARIABILITY OF--DIRECT
EFFECTS OF THE CONDITIONS OF LIFE--CAN WITHSTAND MUCH COLD--BREEDS MUCH
MODIFIED BY SELECTION--COLOURS OF THE HORSE--DAPPLING--DARK STRIPES ON THE
SPINE, LEGS, SHOULDERS, AND FOREHEAD--DUN-COLOURED HORSES MOST FREQUENTLY
STRIPED--STRIPES PROBABLY DUE TO REVERSION TO THE PRIMITIVE STATE OF THE
HORSE.
ASSES.--BREEDS OF--COLOUR OF--LEG- AND SHOULDER-STRIPES--SHOULDER-STRIPES
SOMETIMES ABSENT, SOMETIMES FORKED ... Page 49
CHAPTER III.
PIGS--CATTLE--SHEEP--GOATS.
PIGS BELONG TO TWO DISTINCT TYPES, SUS SCROFA AND
INDICA--TORF-SCHWEIN--JAPAN PIG--FERTILITY OF CROSSED PIGS--CHANGES IN THE
SKULL OF THE HIGHLY CULTIVATED RACES--CONVERGENCE OF
CHARACTER--GESTATION--SOLID-HOOFED SWINE--CURIOUS APPENDAGES TO THE
JAWS--DECREASE IN SIZE OF THE TUSKS--YOUNG PIGS LONGITUDINALLY
STRIPED--FERAL PIGS--CROSSED BREEDS.
CATTLE.--ZEBU A DISTINCT SPECIES--EUROPEAN CATTLE PROBABLY DESCENDED FROM
THREE WILD FORMS--ALL THE RACES NOW FERTILE TOGETHER--BRITISH PARK
CATTLE--ON THE COLOUR OF THE ABORIGINAL SPECIES--CONSTITUTIONAL
DIFFERENCES--SOUTH AFRICAN RACES--SOUTH AMERICAN RACES--NIATA
CATTLE--ORIGIN OF THE VARIOUS RACES OF CATTLE. {iv}
SHEEP.--REMARKABLE RACES OF--VARIATIONS ATTACHED TO THE MALE
SEX--ADAPTATIONS TO VARIOUS CONDITIONS--GESTATION OF--CHANGES IN THE
WOOL--SEMI-MONSTROUS BREEDS.
GOATS.--REMARKABLE VARIATIONS OF ... Page 65
CHAPTER IV.
DOMESTIC RABBITS.
DOMESTIC RABBITS DESCENDED FROM THE COMMON WILD RABBIT--ANCIENT
DOMESTICATION--ANCIENT SELECTION--LARGE LOP-EARED RABBITS--VARIOUS
BREEDS--FLUCTUATING CHARACTERS--ORIGIN OF THE HIMALAYAN BREED--CURIOUS CASE
OF INHERITANCE--FERAL RABBITS IN JAMAICA AND THE FALKLAND ISLANDS--PORTO
SANTO FERAL RABBITS--OSTEOLOGICAL CHARACTERS--SKULL--SKULL OF HALF-LOP
RABBITS--VARIATIONS IN THE SKULL ANALOGOUS TO DIFFERENCES IN DIFFERENT
SPECIES OF HARES--VERTEBRAE--STERNUM--SCAPULA--EFFECTS OF USE AND DISUSE ON
THE PROPORTIONS OF THE LIMBS AND BODY--CAPACITY OF THE SKULL AND REDUCED
SIZE OF THE BRAIN--SUMMARY ON THE MODIFICATIONS OF DOMESTICATED RABBITS ...
Page 103
CHAPTER V.
DOMESTIC PIGEONS.
ENUMERATION AND DESCRIPTION OF THE SEVERAL BREEDS--INDIVIDUAL
VARIABILITY--VARIATIONS OF A REMARKABLE NATURE--OSTEOLOGICAL CHARACTERS:
SKULL, LOWER JAW, NUMBER OF VERTEBRAE--CORRELATION OF GROWTH: TONGUE WITH
BEAK; EYELIDS AND NOSTRILS WITH WATTLED SKIN--NUMBER OF WING-FEATHERS, AND
LENGTH OF WING--COLOUR AND DOWN--WEBBED AND FEATHERED FEET--ON THE EFFECTS
OF DISUSE--LENGTH OF FEET IN CORRELATION WITH LENGTH OF BEAK--LENGTH OF
STERNUM, SCAPULA, AND FURCULA--LENGTH OF WINGS--SUMMARY ON THE POINTS OF
DIFFERENCE IN THE SEVERAL BREEDS ... Page 131
CHAPTER VI.
PIGEONS--_continued_.
ON THE ABORIGINAL PARENT-STOCK OF THE SEVERAL DOMESTIC RACES--HABITS OF
LIFE--WILD RACES OF THE ROCK-PIGEON--DOVECOT-PIGEONS--PROOFS OF THE DESCENT
OF THE SEVERAL RACES FROM COLUMBA LIVIA--FERTILITY OF THE RACES WHEN
CROSSED--REVERSION TO THE PLUMAGE OF THE WILD ROCK-PIGEON--CIRCUMSTANCES
FAVOURABLE TO THE FORMATION OF THE RACES--ANTIQUITY AND HISTORY OF THE
PRINCIPAL RACES--MANNER OF THEIR FORMATION--SELECTION--UNCONSCIOUS
SELECTION--CARE TAKEN BY FANCIERS IN SELECTING THEIR BIRDS--SLIGHTLY
DIFFERENT STRAINS GRADUALLY CHANGE INTO WELL-MARKED BREEDS--EXTINCTION OF
INTERMEDIATE FORMS--CERTAIN BREEDS REMAIN PERMANENT, WHILST OTHERS
CHANGE--SUMMARY ... Page 180
{v}
CHAPTER VII.
FOWLS.
BRIEF DESCRIPTIONS OF THE CHIEF BREEDS--ARGUMENTS IN FAVOUR OF THEIR
DESCENT FROM SEVERAL SPECIES--ARGUMENTS IN FAVOUR OF ALL THE BREEDS HAVING
DESCENDED FROM GALLUS BANKIVA---REVERSION TO THE PARENT-STOCK IN
COLOUR--ANALOGOUS VARIATIONS--ANCIENT HISTORY OF THE FOWL--EXTERNAL
DIFFERENCES BETWEEN THE SEVERAL BREEDS--EGGS--CHICKENS--SECONDARY SEXUAL
CHARACTERS--WING- AND TAIL-FEATHERS, VOICE, DISPOSITION, ETC.--OSTEOLOGICAL
DIFFERENCES IN THE SKULL, VERTEBRAE, ETC.--EFFECTS OF USE AND DISUSE ON
CERTAIN PARTS--CORRELATION OF GROWTH ... Page 225
CHAPTER VIII.
DUCKS--GOOSE--PEACOCK--TURKEY--GUINEA-FOWL--CANARY-BIRD--GOLD-FISH--
HIVE-BEES--SILK-MOTHS.
DUCKS, SEVERAL BREEDS OF--PROGRESS OF DOMESTICATION--ORIGIN OF, FROM THE
COMMON WILD-DUCK--DIFFERENCES IN THE DIFFERENT BREEDS--OSTEOLOGICAL
DIFFERENCES--EFFECTS OF USE AND DISUSE ON THE LIMB-BONES.
GOOSE, ANCIENTLY DOMESTICATED--LITTLE VARIATION OF--SEBASTOPOL BREED.
PEACOCK, ORIGIN OF BLACK-SHOULDERED BREED.
TURKEY, BREEDS OF--CROSSED WITH THE UNITED STATES SPECIES--EFFECTS OF
CLIMATE ON.
GUINEA-FOWL, CANARY-BIRD, GOLD-FISH, HIVE-BEES.
SILK-MOTHS, SPECIES AND BREEDS OF--ANCIENTLY DOMESTICATED--CARE IN THEIR
SELECTION--DIFFERENCES IN THE DIFFERENT RACES--IN THE EGG, CATERPILLAR, AND
COCOON STATES--INHERITANCE OF CHARACTERS--IMPERFECT WINGS--LOST
INSTINCTS--CORRELATED CHARACTERS ... Page 276
CHAPTER IX.
CULTIVATED PLANTS: CEREAL AND CULINARY PLANTS.
PRELIMINARY REMARKS ON THE NUMBER AND PARENTAGE OF CULTIVATED PLANTS--FIRST
STEPS IN CULTIVATION--GEOGRAPHICAL DISTRIBUTION OF CULTIVATED PLANTS.
CEREALIA.--DOUBTS ON THE NUMBER OF SPECIES.--WHEAT: VARIETIES
OF--INDIVIDUAL VARIABILITY--CHANGED HABITS--SELECTION--ANCIENT HISTORY OF
THE VARIETIES.--MAIZE: GREAT VARIATION OF--DIRECT ACTION OF CLIMATE ON.
CULINARY PLANTS.--CABBAGES: VARIETIES OF, IN FOLIAGE AND STEMS, BUT NOT IN
OTHER PARTS--PARENTAGE OF--OTHER SPECIES OF BRASSICA.--PEAS: AMOUNT OF
DIFFERENCE IN THE SEVERAL KINDS, CHIEFLY IN THE PODS AND SEED--SOME
VARIETIES CONSTANT, SOME HIGHLY VARIABLE--DO NOT
INTERCROSS.--BEANS.--POTATOES: NUMEROUS VARIETIES OF--DIFFERING LITTLE,
EXCEPT IN THE TUBERS--CHARACTERS INHERITED ... Page 305
{vi}
CHAPTER X.
PLANTS _continued_--FRUITS--ORNAMENTAL TREES--FLOWERS.
FRUITS.--GRAPES--VARY IN ODD AND TRIFLING PARTICULARS.--MULBERRY.--THE
ORANGE GROUP--SINGULAR RESULTS FROM CROSSING.--PEACH AND
NECTARINE--BUD-VARIATION--ANALOGOUS VARIATION--RELATION TO THE
ALMOND.--APRICOT.--PLUMS--VARIATION IN THEIR STONES.--CHERRIES--SINGULAR
VARIETIES OF.--APPLE.--PEAR.--STRAWBERRY--INTERBLENDING OF THE ORIGINAL
FORMS.--GOOSEBERRY--STEADY INCREASE IN SIZE OF THE FRUIT--VARIETIES
OF.--WALNUT.--NUT.--CUCURBITACEOUS PLANTS--WONDERFUL VARIATION OF.
ORNAMENTAL TREES--THEIR VARIATION IN DEGREE AND
KIND--ASH-TREE--SCOTCH-FIR--HAWTHORN.
FLOWERS--MULTIPLE ORIGIN OF MANY KINDS--VARIATION IN CONSTITUTIONAL
PECULIARITIES--KIND OF VARIATION.--ROSES--SEVERAL SPECIES
CULTIVATED.--PANSY.--DAHLIA.--HYACINTH, HISTORY AND VARIATION OF ... Page
332
CHAPTER XI.
ON BUD-VARIATION, AND ON CERTAIN ANOMALOUS MODES OF REPRODUCTION AND
VARIATION.
BUD-VARIATIONS IN THE PEACH, PLUM, CHERRY, VINE, GOOSEBERRY, CURRANT, AND
BANANA, AS SHOWN BY THE MODIFIED FRUIT--IN FLOWERS: CAMELLIAS, AZALEAS,
CHRYSANTHEMUMS, ROSES, ETC.--ON THE RUNNING OF THE COLOUR IN
CARNATIONS--BUD-VARIATIONS IN LEAVES--VARIATIONS BY SUCKERS, TUBERS, AND
BULBS--ON THE BREAKING OF TULIPS--BUD-VARIATIONS GRADUATE INTO CHANGES
CONSEQUENT ON CHANGED CONDITIONS OF LIFE--CYTISUS ADAMI, ITS ORIGIN AND
TRANSFORMATION--ON THE UNION OF TWO DIFFERENT EMBRYOS IN ONE SEED--THE
TRIFACIAL ORANGE--ON REVERSION BY BUDS IN HYBRIDS AND MONGRELS--ON THE
PRODUCTION OF MODIFIED BUDS BY THE GRAFTING OF ONE VARIETY OR SPECIES ON
ANOTHER--ON THE DIRECT OR IMMEDIATE ACTION OF FOREIGN POLLEN ON THE
MOTHER-PLANT--ON THE EFFECTS IN FEMALE ANIMALS OF A FIRST IMPREGNATION ON
THE SUBSEQUENT OFFSPRING--CONCLUSION AND SUMMARY ... Page 373
* * * * *
{vii}
LIST OF ILLUSTRATIONS.
1. DUN DEVONSHIRE PONY, WITH SHOULDER, SPINAL, AND LEG STRIPES ... PAGE
56
2. HEAD OF JAPAN OR MASKED PIG ... 69
3. HEAD OF WILD BOAR, AND OF "GOLDEN DAYS," A PIG OF THE YORKSHIRE LARGE
BREED ... 72
4. OLD IRISH PIG, WITH JAW-APPENDAGES ... 75
5. HALF-LOP RABBIT ... 108
6. SKULL OF WILD RABBIT ... 117
7. SKULL OF LARGE LOP-EARED RABBIT ... 117
8. PART OF ZYGOMATIC ARCH, SHOWING THE PROJECTING END OF THE MALAR-BONE,
AND THE AUDITORY MEATUS, OF RABBITS ... 118
9. POSTERIOR END OF SKULL, SHOWING THE INTER-PARIETAL BONE, OF RABBITS
... 118
10. OCCIPITAL FORAMEN OF RABBITS ... 118
11. SKULL OF HALF-LOP RABBIT ... 119
12. ATLAS VERTEBRAE OF RABBITS ... 121
13. THIRD CERVICAL VERTEBRAE OF RABBITS ... 121
14. DORSAL VERTEBRAE, FROM SIXTH TO TENTH INCLUSIVE, OF RABBITS ... 122
15. TERMINAL BONE OF STERNUM OF RABBITS ... 123
16. ACROMION OF SCAPULA OF RABBITS ... 123
17. THE ROCK-PIGEON, OR COLUMBIA LIVIA ... 135
18. ENGLISH POUTER ... 137
19. ENGLISH CARRIER ... 140
20. ENGLISH BARB ... 145
21. ENGLISH FANTAIL ... 147
22. AFRICAN OWL ... 149
23. SHORT-FACED ENGLISH TUMBLER ... 152
24. SKULLS OF PIGEONS, VIEWED LATERALLY ... 163
25. LOWER JAWS OF PIGEONS, SEEN FROM ABOVE ... 164
26. SKULL OF RUNT, SEEN FROM ABOVE ... 165
27. LATERAL VIEW OF JAWS OF PIGEONS ... 165
28. SCAPULAE OF PIGEONS ... 167
29. FURCULAE OF PIGEONS ... 167
30. SPANISH FOWL ... 226
31. HAMBURGH FOWL ... 228
32. POLISH FOWL ... 229
33. OCCIPITAL FORAMEN OF THE SKULLS OF FOWLS ... 261
{viii}
34. SKULLS OF FOWLS, VIEWED FROM ABOVE, A LITTLE OBLIQUELY ... 262
35. LONGITUDINAL SECTIONS OF SKULLS OF FOWLS, VIEWED LATERALLY ... 263
36. SKULL OF HORNED FOWL, VIEWED FROM ABOVE, A LITTLE OBLIQUELY ... 265
37. SIXTH CERVICAL VERTEBRAE OF FOWLS, VIEWED LATERALLY ... 267
38. EXTREMITY OF THE FURCULA OF FOWLS, VIEWED LATERALLY ... 268
39. SKULLS OF DUCKS, VIEWED LATERALLY, REDUCED TO TWO-THIRDS OF THE
NATURAL SIZE ... 282
40. CERVICAL VERTEBRAE OF DUCKS, OF NATURAL SIZE ... 283
41. PODS OF THE COMMON PEA ... 328
42. PEACH AND ALMOND STONES, OF NATURAL SIZE, VIEWED EDGEWAYS ... 337
43. PLUM STONES, OF NATURAL SIZE, VIEWED LATERALLY ... 345
* * * * *
{1}
THE
VARIATION OF ANIMALS AND PLANTS
UNDER DOMESTICATION.
* * * * *
INTRODUCTION.
The object of this work is not to describe all the many races of animals
which have been domesticated by man, and of the plants which have been
cultivated by him; even if I possessed the requisite knowledge, so gigantic
an undertaking would be here superfluous. It is my intention to give under
the head of each species only such facts as I have been able to collect or
observe, showing the amount and nature of the changes which animals and
plants have undergone whilst under man's dominion, or which bear on the
general principles of variation. In one case alone, namely in that of the
domestic pigeon, I will describe fully all the chief races, their history,
the amount and nature of their differences, and the probable steps by which
they have been formed. I have selected this case, because, as we shall
hereafter see, the materials are better than in any other; and one case
fully described will in fact illustrate all others. But I shall also
describe domesticated rabbits, fowls, and ducks, with considerable
fullness.
The subjects discussed in this volume are so connected that it is not a
little difficult to decide how they can be best arranged. I have determined
in the first part to give, under the heads of the various animals and
plants, a large body of facts, some of which may at first appear but little
related to our subject, and to devote the latter part to general
discussions. Whenever I have found it necessary to give numerous details,
in support of any proposition or conclusion, small type has been used. The
reader {2} will, I think, find this plan a convenience, for, if he does not
doubt the conclusion or care about the details, he can easily pass them
over; yet I may be permitted to say that some of the discussions thus
printed deserve attention, at least from the professed naturalist.
It may be useful to those who have read nothing about Natural Selection, if
I here give a brief sketch of the whole subject and of its bearing on the
origin of species.[1] This is the more desirable, as it is impossible in
the present work to avoid many allusions to questions which will be fully
discussed in future volumes.
From a remote period, in all parts of the world, man has subjected many
animals and plants to domestication or culture. Man has no power of
altering the absolute conditions of life; he cannot change the climate of
any country; he adds no new element to the soil; but he can remove an
animal or plant from one climate or soil to another, and give it food on
which it did not subsist in its natural state. It is an error to speak of
man "tampering with nature" and causing variability. If organic beings had
not possessed an inherent tendency to vary, man could have done nothing.[2]
He unintentionally exposes his animals and plants to various conditions of
life, and variability supervenes, which he cannot even prevent or check.
Consider the simple case of a plant which has been cultivated during a long
time in its native country, and which consequently has not been subjected
to any change of climate. It has been protected to a certain extent from
the competing roots of plants of other kinds; it has generally been grown
in manured soil, but probably not richer than that of many an alluvial
flat; and lastly, it has been exposed to changes in its conditions, being
grown sometimes in one district and sometimes in another, in different
soils. Under such circumstances, {3} scarcely a plant can be named, though
cultivated in the rudest manner, which has not given birth to several
varieties. It can hardly be maintained that during the many changes which
this earth has undergone, and during the natural migrations of plants from
one land or island to another, tenanted by different species, that such
plants will not often have been subjected to changes in their conditions
analogous to those which almost inevitably cause cultivated plants to vary.
No doubt man selects varying individuals, sows their seeds, and again
selects their varying offspring. But the initial variation on which man
works, and without which he can do nothing, is caused by slight changes in
the conditions of life, which must often have occurred under nature. Man,
therefore, may be said to have been trying an experiment on a gigantic
scale; and it is an experiment which nature during the long lapse of time
has incessantly tried. Hence it follows that the principles of
domestication are important for us. The main result is that organic beings
thus treated have varied largely, and the variations have been inherited.
This has apparently been one chief cause of the belief long held by some
few naturalists that species in a state of nature undergo change.
I shall in this volume treat, as fully as my materials permit, the whole
subject of variation under domestication. We may thus hope to obtain some
light, little though it be, on the causes of variability,--on the laws
which govern it, such as the direct action of climate and food, the effects
of use and disuse, and of correlation of growth,--and on the amount of
change to which domesticated organisms are liable. We shall learn something
on the laws of inheritance, on the effects of crossing different breeds,
and on that sterility which often supervenes when organic beings are
removed from their natural conditions of life, and likewise when they are
too closely interbred. During this investigation we shall see that the
principle of Selection is all important. Although man does not cause
variability and cannot even prevent it, he can select, preserve, and
accumulate the variations given to him by the hand of nature in any way
which he chooses; and thus he can certainly produce a great result.
Selection may be followed either methodically and intentionally, or
unconsciously and unintentionally. Man {4} may select and preserve each
successive variation, with the distinct intention of improving and altering
a breed, in accordance with a preconceived idea; and by thus adding up
variations, often so slight as to be imperceptible by an uneducated eye, he
has effected wonderful changes and improvements. It can, also, be clearly
shown that man, without any intention or thought of improving the breed, by
preserving in each successive generation the individuals which he prizes
most, and by destroying the worthless individuals, slowly, though surely,
induces great changes. As the will of man thus comes into play, we can
understand how it is that domesticated breeds show adaptation to his wants
and pleasures. We can further understand how it is that domestic races of
animals and cultivated races of plants often exhibit an abnormal character,
as compared with natural species; for they have been modified not for their
own benefit, but for that of man.
In a second work I shall discuss the variability of organic beings in a
state of nature; namely, the individual differences presented by animals
and plants, and those slightly greater and generally inherited differences
which are ranked by naturalists as varieties or geographical races. We
shall see how difficult, or rather how impossible it often is, to
distinguish between races and sub-species, as the less well-marked forms
have sometimes been denominated; and again between sub-species and true
species. I shall further attempt to show that it is the common and widely
ranging, or, as they may be called, the dominant species, which most
frequently vary; and that it is the large and flourishing genera which
include the greatest number of varying species. Varieties, as we shall see,
may justly be called incipient species.
But it may be urged, granting that organic beings in a state of nature
present some varieties,--that their organization is in some slight degree
plastic; granting that many animals and plants have varied greatly under
domestication, and that man by his power of selection has gone on
accumulating such variations until he has made strongly marked and firmly
inherited races; granting all this, how, it may be asked, have species
arisen in a state of nature? The differences between natural varieties are
slight; whereas the differences are {5} considerable between the species of
the same genus, and great between the species of distinct genera. How do
these lesser differences become augmented into the greater difference? How
do varieties, or as I have called them incipient species, become converted
into true and well-defined species? How has each new species been adapted
to the surrounding physical conditions, and to the other forms of life on
which it in any way depends? We see on every side of us innumerable
adaptations and contrivances, which have justly excited in the mind of
every observer the highest admiration. There is, for instance, a fly
(Cecidomyia)[3] which deposits its eggs within the stamens of a
Scrophularia, and secretes a poison which produces a gall, on which the
larva feeds; but there is another insect (Misocampus) which deposits its
eggs within the body of the larva within the gall, and is thus nourished by
its living prey; so that here a hymenopterous insect depends on a dipterous
insect, and this depends on its power of producing a monstrous growth in a
particular organ of a particular plant. So it is, in a more or less plainly
marked manner, in thousands and tens of thousands of cases, with the lowest
as well as with the highest productions of nature.
This problem of the conversion of varieties into species,--that is, the
augmentation of the slight differences characteristic of varieties into the
greater differences characteristic of species and genera, including the
admirable adaptations of each being to its complex organic and inorganic
conditions of life,--will form the main subject of my second work. We shall
therein see that all organic beings, without exception, tend to increase at
so high a ratio, that no district, no station, not even the whole surface
of the land or the whole ocean, would hold the progeny of a single pair
after a certain number of generations. The inevitable result is an
ever-recurrent Struggle for Existence. It has truly been said that all
nature is at war; the strongest ultimately prevail, the weakest fail; and
we well know that myriads of forms have disappeared from the face of the
earth. If then organic beings in a state of nature vary even in a slight
degree, owing to changes in the surrounding {6} conditions, of which we
have abundant geological evidence, or from any other cause; if, in the long
course of ages, inheritable variations ever arise in any way advantageous
to any being under its excessively complex and changing relations of life;
and it would be a strange fact if beneficial variations did never arise,
seeing how many have arisen which man has taken advantage of for his own
profit or pleasure; if then these contingencies ever occur, and I do not
see how the probability of their occurrence can be doubted, then the severe
and often-recurrent struggle for existence will determine that those
variations, however slight, which are favourable shall be preserved or
selected, and those which are unfavourable shall be destroyed.
This preservation, during the battle for life, of varieties which possess
any advantage in structure, constitution, or instinct, I have called
Natural Selection; and Mr. Herbert Spencer has well expressed the same idea
by the Survival of the Fittest. The term "natural selection" is in some
respects a bad one, as it seems to imply conscious choice; but this will be
disregarded after a little familiarity. No one objects to chemists speaking
of "elective affinity;" and certainly an acid has no more choice in
combining with a base, than the conditions of life have in determining
whether or not a new form be selected or preserved. The term is so far a
good one as it brings into connection the production of domestic races by
man's power of selection, and the natural preservation of varieties and
species in a state of nature. For brevity sake I sometimes speak of natural
selection as an intelligent power;--in the same way as astronomers speak of
the attraction of gravity as ruling the movements of the planets, or as
agriculturists speak of man making domestic races by his power of
selection. In the one case, as in the other, selection does nothing without
variability, and this depends in some manner on the action of the
surrounding circumstances on the organism. I have, also, often personified
the word Nature; for I have found it difficult to avoid this ambiguity; but
I mean by nature only the aggregate action and product of many natural
laws,--and by laws only the ascertained sequence of events. {7}
In the chapter devoted to natural selection I shall show from experiment
and from a multitude of facts, that the greatest amount of life can be
supported on each spot by great diversification or divergence in the
structure and constitution of its inhabitants. We shall, also, see that the
continued production of new forms through natural selection, which implies
that each new variety has some advantage over others, almost inevitably
leads to the extermination of the older and less improved forms. These
latter are almost necessarily intermediate in structure as well as in
descent between the last-produced forms and their original parent-species.
Now, if we suppose a species to produce two or more varieties, and these in
the course of time to produce other varieties, the principle of good being
derived from diversification of structure will generally lead to the
preservation of the most divergent varieties; thus the lesser differences
characteristic of varieties come to be augmented into the greater
differences characteristic of species, and, by the extermination of the
older intermediate forms, new species come to be distinctly defined
objects. Thus, also, we shall see how it is that organic beings can be
classed by what is called a natural method in distinct groups--species
under genera, and genera under families.
As all the inhabitants of each country may be said, owing to their high
rate of reproduction, to be striving to increase in numbers; as each form
is related to many other forms in the struggle for life,--for destroy any
one and its place will be seized by others; as every part of the
organization occasionally varies in some slight degree, and as natural
selection acts exclusively by the preservation of variations which are
advantageous under the excessively complex conditions to which each being
is exposed, no limit exists to the number, singularity, and perfection of
the contrivances and co-adaptations which may thus be produced. An animal
or a plant may thus slowly become related in its structure and habits in
the most intricate manner to many other animals and plants, and to the
physical conditions of its home. Variations in the organization will in
some cases be aided by habit, or by the use and disuse of parts, and they
will be governed by the direct action {8} of the surrounding physical
conditions and by correlation of growth.
On the principles here briefly sketched out, there is no innate or
necessary tendency in each being to its own advancement in the scale of
organization. We are almost compelled to look at the specialization or
differentiation of parts or organs for different functions as the best or
even sole standard of advancement; for by such division of labour each
function of body and mind is better performed. And, as natural selection
acts exclusively through the preservation of profitable modifications of
structure, and as the conditions of life in each area generally become more
and more complex, from the increasing number of different forms which
inhabit it and from most of these forms acquiring a more and more perfect
structure, we may confidently believe, that, on the whole, organization
advances. Nevertheless a very simple form fitted for very simple conditions
of life might remain for indefinite ages unaltered or unimproved; for what
would it profit an infusorial animalcule, for instance, or an intestinal
worm, to become highly organized? Members of a high group might even
become, and this apparently has occurred, fitted for simpler conditions of
life; and in this case natural selection would tend to simplify or degrade
the organization, for complicated mechanism for simple actions would be
useless or even disadvantageous.
In a second work, after treating of the Variation of organisms in a state
of nature, of the Struggle for Existence and the principle of Natural
Selection, I shall discuss the difficulties which are opposed to the
theory. These difficulties may be classed under the following heads:--the
apparent impossibility in some cases of a very simple organ graduating by
small steps into a highly perfect organ; the marvellous facts of Instinct;
the whole question of Hybridity; and, lastly, the absence, at the present
time and in our geological formations, of innumerable links connecting all
allied species. Although some of these difficulties are of great weight, we
shall see that many of them are explicable on the theory of natural
selection, and are otherwise inexplicable.
In scientific investigations it is permitted to invent any hypothesis, and
if it explains various large and independent classes of facts it rises to
the rank of a well-grounded theory. The {9} undulations of the ether and
even its existence are hypothetical, yet every one now admits the
undulatory theory of light. The principle of natural selection may be
looked at as a mere hypothesis, but rendered in some degree probable by
what we positively know of the variability of organic beings in a state of
nature,--by what we positively know of the struggle for existence, and the
consequent almost inevitable preservation of favourable variations,--and
from the analogical formation of domestic races. Now this hypothesis may be
tested,--and this seems to me the only fair and legitimate manner of
considering the whole question,--by trying whether it explains several
large and independent classes of facts; such as the geological succession
of organic beings, their distribution in past and present times, and their
mutual affinities and homologies. If the principle of natural selection
does explain these and other large bodies of facts, it ought to be
received. On the ordinary view of each species having been independently
created, we gain no scientific explanation of any one of these facts. We
can only say that it has so pleased the Creator to command that the past
and present inhabitants of the world should appear in a certain order and
in certain areas; that He has impressed on them the most extraordinary
resemblances, and has classed them in groups subordinate to groups. But by
such statements we gain no new knowledge; we do not connect together facts
and laws; we explain nothing.
In a third work I shall try the principle of natural selection by seeing
how far it will give a fair explanation of the several classes of facts
just alluded to. It was the consideration of these facts which first led me
to take up the present subject. When I visited, during the voyage of H.M.S.
_Beagle_, the Galapagos Archipelago, situated in the Pacific Ocean about
500 miles from the shore of South America, I found myself surrounded by
peculiar species of birds, reptiles, and plants, existing nowhere else in
the world. Yet they nearly all bore an American stamp. In the song of the
mocking-thrush, in the harsh cry of the carrion-hawk, in the great
candlestick-like opuntias, I clearly perceived the neighbourhood of
America, though the islands were separated by so many miles of ocean from
the mainland, and differed much from it in their geological {10}
constitution and climate. Still more surprising was the fact that most of
the inhabitants of each separate island in this small archipelago were
specifically different, though most closely related to each other. The
archipelago, with its innumerable craters and bare streams of lava,
appeared to be of recent origin; and thus I fancied myself brought near to
the very act of creation. I often asked myself how these many peculiar
animals and plants had been produced: the simplest answer seemed to be that
the inhabitants of the several islands had descended from each other,
undergoing modification in the course of their descent; and that all the
inhabitants of the archipelago had descended from those of the nearest
land, namely America, whence colonists would naturally have been derived.
But it long remained to me an inexplicable problem how the necessary degree
of modification could have been effected, and it would have thus remained
for ever, had I not studied domestic productions, and thus acquired a just
idea of the power of Selection. As soon as I had fully realized this idea,
I saw, on reading Malthus on Population, that Natural Selection was the
inevitable result of the rapid increase of all organic beings; for I was
prepared to appreciate the struggle for existence by having long studied
the habits of animals.
Before visiting the Galapagos I had collected many animals whilst
travelling from north to south on both sides of America, and everywhere,
under conditions of life as different as it is possible to conceive,
American forms were met with--species replacing species of the same
peculiar genera. Thus it was when the Cordilleras were ascended, or the
thick tropical forests penetrated, or the fresh waters of America searched.
Subsequently I visited other countries, which in all the conditions of life
were incomparably more like to parts of South America, than the different
parts of that continent were to each other; yet in these countries, as in
Australia or Southern Africa, the traveller cannot fail to be struck with
the entire difference of their productions. Again the reflection was forced
on me that community of descent from the early inhabitants or colonists of
South America would alone explain the wide prevalence of American types of
structure throughout that immense area.
To exhume with one's own hands the bones of extinct and {11} gigantic
quadrupeds brings the whole question of the succession of species vividly
before one's mind; and I had found in South America great pieces of
tesselated armour exactly like, but on a magnificent scale, that covering
the pigmy armadillo; I had found great teeth like those of the living
sloth, and bones like those of the cavy. An analogous succession of allied
forms had been previously observed in Australia. Here then we see the
prevalence, as if by descent, in time as in space, of the same types in the
same areas; and in neither case does the similarity of the conditions by
any means seem sufficient to account for the similarity of the forms of
life. It is notorious that the fossil remains of closely consecutive
formations are closely allied in structure, and we can at once understand
the fact if they are likewise closely allied by descent. The succession of
the many distinct species of the same genus throughout the long series of
geological formations seems to have been unbroken or continuous. New
species come in gradually one by one. Ancient and extinct forms of life
often show combined or intermediate characters, like the words of a dead
language with respect to its several offshoots or living tongues. All these
and other such facts seemed to me to point to descent with modification as
the method of production of new groups of species.
The innumerable past and present inhabitants of the world are connected
together by the most singular and complex affinities, and can be classed in
groups under groups, in the same manner as varieties can be classed under
species and sub-varieties under varieties, but with much higher grades of
difference. It will be seen in my third work that these complex affinities
and the rules for classification receive a rational explanation on the
principle of descent, together with modifications acquired through natural
selection, entailing divergence of character and the extinction of
intermediate forms. How inexplicable is the similar pattern of the hand of
a man, the foot of a dog, the wing of a bat, the flipper of a seal, on the
doctrine of independent acts of creation! how simply explained on the
principle of the natural selection of successive slight variations in the
diverging descendants from {12} a single progenitor! So it is, if we look
to the structure of an individual animal or plant, when we see the fore and
hind limbs, the skull and vertebrae, the jaws and legs of a crab, the
petals, stamens, and pistils of a flower, built on the same type or
pattern. During the many changes to which in the course of time all organic
beings have been subjected, certain organs or parts have occasionally
become at first of little use and ultimately superfluous; and the retention
of such parts in a rudimentary and utterly useless condition can, on the
descent-theory, be simply understood. On the principle of modifications
being inherited at the same age in the child, at which each successive
variation first appeared in the parent, we shall see why rudimentary parts
and organs are generally well developed in the individual at a very early
age. On the same principle of inheritance at corresponding ages, and on the
principle of variations not generally supervening at a very early period of
embryonic growth (and both these principles can be shown to be probable
from direct evidence), that most wonderful fact in the whole round of
natural history, namely, the similarity of members of the same great class
in their embryonic condition,--the embryo, for instance, of a mammal, bird,
reptile, and fish being barely distinguishable,--becomes simply
intelligible.
It is the consideration and explanation of such facts as these which has
convinced me that the theory of descent with modification by means of
natural selection is in the main true. These facts have as yet received no
explanation on the theory of independent Creations; they cannot be grouped
together under one point of view, but each has to be considered as an
ultimate fact. As the first origin of life on this earth, as well as the
continued life of each individual, is at present quite beyond the scope of
science, I do not wish to lay much stress on the greater simplicity of the
view of a few forms, or of only one form, having been originally created,
instead of innumerable miraculous creations having been necessary at
innumerable periods; though this more simple view accords well with
Maupertuis's philosophical axiom "of least action."
In considering how far the theory of natural selection may be {13}
extended,--that is, in determining from how many progenitors the
inhabitants of the world have descended,--we may conclude that at least all
the members of the same class have descended from a single ancestor. A
number of organic beings are included in the same class, because they
present, independently of their habits of life, the same fundamental type
of structure, and because they graduate into each other. Moreover, members
of the same class can in most cases be shown to be closely alike at an
early embryonic age. These facts can be explained on the belief of their
descent from a common form; therefore it may be safely admitted that all
the members of the same class have descended from one progenitor. But as
the members of quite distinct classes have something in common in structure
and much in common in constitution, analogy and the simplicity of the view
would lead us one step further, and to infer as probable that all living
creatures have descended from a single prototype.
I hope that the reader will pause before coming to any final and hostile
conclusion on the theory of natural selection. It is the facts and views to
be hereafter given which have convinced me of the truth of the theory. The
reader may consult my 'Origin of Species,' for a general sketch of the
whole subject; but in that work he has to take many statements on trust. In
considering the theory of natural selection, he will assuredly meet with
weighty difficulties, but these difficulties relate chiefly to
subjects--such as the degree of perfection of the geological record, the
means of distribution, the possibility of transitions in organs, &c.--on
which we are confessedly ignorant; nor do we know how ignorant we are. If
we are much more ignorant than is generally supposed, most of these
difficulties wholly disappear. Let the reader reflect on the difficulty of
looking at whole classes of facts from a new point of view. Let him observe
how slowly, but surely, the noble views of Lyell on the gradual changes now
in progress on the earth's surface have been accepted as sufficient to
account for all that we see in its past history. The present action of
natural selection may seem more or less probable; but I believe in the
truth of the theory, {14} because it collects under one point of view, and
gives a rational explanation of, many apparently independent classes of
facts.[4]
* * * * *
{15}
CHAPTER I.
DOMESTIC DOGS AND CATS.
ANCIENT VARIETIES OF THE DOG--RESEMBLANCE OF DOMESTIC DOGS IN VARIOUS
COUNTRIES TO NATIVE CANINE SPECIES--ANIMALS NOT ACQUAINTED WITH MAN AT
FIRST FEARLESS--DOGS RESEMBLING WOLVES AND JACKALS--HABIT OF BARKING
ACQUIRED AND LOST--FERAL DOGS--TAN-COLOURED EYE-SPOTS PERIOD OF
GESTATION--OFFENSIVE ODOUR--FERTILITY OF THE RACES WHEN
CROSSED--DIFFERENCES IN THE SEVERAL RACES IN PART DUE TO DESCENT FROM
DISTINCT SPECIES--DIFFERENCES IN THE SKULL AND TEETH--DIFFERENCES IN
THE BODY, IN CONSTITUTION--FEW IMPORTANT DIFFERENCES HAVE BEEN FIXED BY
SELECTION--DIRECT ACTION OF CLIMATE--WATER-DOGS WITH PALMATED
FEET--HISTORY OF THE CHANGES WHICH CERTAIN ENGLISH RACES OF THE DOG
HAVE GRADUALLY UNDERGONE THROUGH SELECTION--EXTINCTION OF THE LESS
IMPROVED SUB-BREEDS.
CATS, CROSSED WITH SEVERAL SPECIES--DIFFERENT BREEDS FOUND ONLY IN
SEPARATED COUNTRIES--DIRECT EFFECTS OF THE CONDITIONS OF LIFE--FERAL
CATS--INDIVIDUAL VARIABILITY.
The first and chief point of interest in this chapter is, whether the
numerous domesticated varieties of the dog have descended from a single
wild species, or from several. Some authors believe that all have descended
from the wolf, or from the jackal, or from an unknown and extinct species.
Others again believe, and this of late has been the favourite tenet, that
they have descended from several species, extinct and recent, more or less
commingled together. We shall probably never be able to ascertain their
origin with certainty. Palaeontology[5] does not throw much light on the
question, owing, on the one hand, to the close similarity of the skulls of
extinct as well as living wolves and jackals, and owing on the other hand
to the great dissimilarity of the skulls of the several breeds of the
domestic dogs. It seems, however, that remains have been found in the {16}
later tertiary deposits more like those of a large dog than of a wolf,
which favours the belief of De Blainville that our dogs are the descendants
of a single extinct species. On the other hand, some authors go so far as
to assert that every chief domestic breed must have had its wild prototype.
This latter view is extremely improbable; it allows nothing for variation;
it passes over the almost monstrous character of some of the breeds; and it
almost necessarily assumes, that a large number of species have become
extinct since man domesticated the dog; whereas we plainly see that the
members of the dog-family are extirpated by human agency with much
difficulty; even so recently as 1710 the wolf existed in so small an island
as Ireland.
The reasons which have led various authors to infer that our dogs have
descended from more than one wild species are as follows.[6] Firstly, the
great difference between the several breeds; but this will appear of
comparatively little weight, after we shall have seen how great are the
differences between the several races of various domesticated animals which
certainly have descended from a single parent-form. Secondly, the more
important fact that, at the most anciently known historical periods,
several breeds of the dog existed, very unlike each other, and closely
resembling or identical with breeds still alive.
We will briefly run back through the historical records. The materials are
remarkably deficient between the fourteenth century and the Roman classical
period.[7] At this earlier period {17} various breeds, namely hounds,
house-dogs, lapdogs, &c., existed; but as Dr. Walther has remarked it is
impossible to recognise the greater number with any certainty. Youatt,
however, gives a drawing of a beautiful sculpture of two greyhound puppies
from the Villa of Antoninus. On an Assyrian monument, about 640 B.C., an
enormous mastiff[8] is figured; and according to Sir H. Rawlinson (as I was
informed at the British Museum), similar dogs are still imported into this
same country. I have looked through the magnificent works of Lepsius and
Rosellini, and on the monuments from the fourth to the twelfth dynasties
(_i.e._ from about 3400 B.C. to 2100 B.C.) several varieties of the dog are
represented; most of them are allied to greyhounds; at the later of these
periods a dog resembling a hound is figured, with drooping ears, but with a
longer back and more pointed head than in our hounds. There is, also, a
turnspit, with short and crooked legs, closely resembling the existing
variety; but this kind of monstrosity is so common with various animals, as
with the ancon sheep, and even, according to Rengger, with jaguars in
Paraguay, that it would be rash to look at the monumental animal as the
parent of all our turnspits: Colonel Sykes[9] also has described an Indian
Pariah dog as presenting the same monstrous character. The most ancient dog
represented on the Egyptian monuments is one of the most singular; it
resembles a greyhound, but has long pointed ears and a short curled tail: a
closely allied variety still exists in Northern Africa; for Mr. E. Vernon
Harcourt[10] states that the Arab boar-hound is "an eccentric hieroglyphic
animal, such as Cheops once hunted with, somewhat resembling the rough
Scotch deer-hound; their tails are curled tight round on their backs, {18}
and their ears stick out at right angles." With this most ancient variety a
pariah-like dog coexisted.
We thus see that, at a period between four and five thousand years ago,
various breeds, viz. pariah dogs, greyhounds, common hounds, mastiffs,
house-dogs, lapdogs, and turnspits, existed, more or less closely
resembling our present breeds. But there is not sufficient evidence that
any of these ancient dogs belonged to the same identical sub-varieties with
our present dogs.[11] As long as man was believed to have existed on this
earth only about 6000 years, this fact of the great diversity of the breeds
at so early a period was an argument of much weight that they had proceeded
from several wild sources, for there would not have been sufficient time
for their divergence and modification. But now that we know, from the
discovery of flint tools embedded with the remains of extinct animals in
districts which have since undergone great geographical changes, that man
has existed for an incomparably longer period, and bearing in mind that the
most barbarous nations possess domestic dogs, the argument from
insufficient time falls away greatly in value.
Long before the period of any historical record the dog was domesticated in
Europe. In the Danish Middens of the Neolithic or Newer Stone period, bones
of a canine animal are imbedded, and Steenstrup ingeniously argues that
these belonged to a domestic dog; for a very large proportion of the bones
of birds preserved in the refuse, consists of long bones, which it was
found on trial dogs cannot devour.[12] This ancient dog was succeeded in
Denmark during the Bronze period by a larger kind, presenting certain
differences, and this again during the Iron period, by a still larger kind.
In Switzerland, we hear {19} from Prof. Ruetimeyer,[13] that during the
Neolithic period a domesticated dog of middle size existed, which in its
skull was about equally remote from the wolf and jackal, and partook of the
characters of our hounds and setters or spaniels (Jagdhund und
Wachtelhund). Ruetimeyer insists strongly on the constancy of form during a
very long period of time of this the most ancient known dog. During the
Bronze period a larger dog appeared, and this closely resembled in its jaw
a dog of the same age in Denmark. Remains of two notably distinct varieties
of the dog were found by Schmerling in a cave;[14] but their age cannot be
positively determined.
The existence of a single race, remarkably constant in form during the
whole Neolithic period, is an interesting fact in contrast with what we see
of the changes which the races underwent during the period of the
successive Egyptian monuments, and in contrast with our existing dogs. The
character of this animal during the Neolithic period, as given by
Ruetimeyer, supports De Blainville's view that our varieties have descended
from an unknown and extinct form. But we should not forget that we know
nothing with respect to the antiquity of man in the warmer parts of the
world. The succession of the different kinds of dogs in Switzerland and
Denmark is thought to be due to the immigration of conquering tribes
bringing with them their dogs; and this view accords with the belief that
different wild canine animals were domesticated in different regions.
Independently of the immigration of new races of man, we know from the
wide-spread presence of bronze, composed of an alloy of tin, how much
commerce there must have been throughout Europe at an extremely remote
period, and dogs would then probably have been bartered. At the present
time, amongst the savages of the interior of Guiana, the Taruma Indians are
considered the best trainers of dogs, and possess a large breed, which they
barter at a high price with other tribes.[15]
The main argument in favour of the several breeds of the {20} dog being the
descendants of distinct wild stocks, is their resemblance in various
countries to distinct species still existing there. It must, however, be
admitted that the comparison between the wild and domesticated animal has
been made but in few cases with sufficient exactness. Before entering on
details, it will be well to show that there is no a priori difficulty in
the belief that several canine species have been domesticated; for there is
much difficulty in this respect with some other domestic quadrupeds and
birds. Members of the dog family inhabit nearly the whole world; and
several species agree pretty closely in habits and structure with our
several domesticated dogs. Mr. Galton has shown[16] how fond savages are of
keeping and taming animals of all kinds. Social animals are the most easily
subjugated by man, and several species of Canidae hunt in packs. It deserves
notice, as bearing on other animals as well as on the dog, that at an
extremely ancient period, when man first entered any country, the animals
living there would have felt no instinctive or inherited fear of him, and
would consequently have been tamed far more easily than at present. For
instance, when the Falkland Islands were first visited by man, the large
wolf-like dog (_Canis antarcticus_) fearlessly came to meet Byron's
sailors, who, mistaking this ignorant curiosity for ferocity, ran into the
water to avoid them: even recently a man, by holding a piece of meat in one
hand and a knife in the other, could sometimes stick them at night. On an
island in the Sea of Aral, when first discovered by Butakoff, the saigak
antelopes, which are "generally very timid and watchful, did not fly from
us, but on the contrary looked at us with a sort of curiosity." So, again,
on the shores of the Mauritius, the manatee was not at first in the least
afraid of man, and thus it has been in several quarters of the world with
seals and the morse. I have elsewhere shown[17] how slowly the native birds
of several islands have acquired and inherited a salutary dread of man: at
the Galapagos Archipelago I pushed with the muzzle of my gun hawks from a
branch, and {21} held out a pitcher of water for other birds to alight on
and drink. Quadrupeds and birds which have seldom been disturbed by man,
dread him no more than do our English birds the cows or horses grazing in
the fields.
It is a more important consideration that several canine species evince (as
will be shown in a future chapter) no strong repugnance or inability to
breed under confinement; and the incapacity to breed under confinement is
one of the commonest bars to domestication. Lastly, savages set the highest
value, as we shall see in the chapter on Selection, on dogs: even
half-tamed animals are highly useful to them: the Indians of North America
cross their half-wild dogs with wolves, and thus render them even wilder
than before, but bolder: the savages of Guiana catch and partially tame and
use the whelps of two wild species of _Canis_, as do the savages of
Australia those of the wild Dingo. Mr. Philip King informs me that he once
trained a wild Dingo puppy to drive cattle, and found it very useful. From
these several considerations we see that there is no difficulty in
believing that man might have domesticated various canine species in
different countries. It would indeed have been a strange fact if one
species alone had been domesticated throughout the world.
We will now enter into details. The accurate and sagacious Richardson says,
"The resemblance between the Northern American wolves (_Canis lupus, var.
occidentalis_) and the domestic dogs of the Indians is so great that the
size and strength of the wolf seems to be the only difference. I have more
than once mistaken a band of wolves for the dogs of a party of Indians; and
the howl of the animals of both species is prolonged so exactly in the same
key that even the practised ear of the Indian fails at times to
discriminate them." He adds that the more northern Esquimaux dogs are not
only extremely like the grey wolves of the Arctic circle in form and
colour, but also nearly equal them in size. Dr. Kane has often seen in his
teams of sledge-dogs the oblique eye (a character on which some naturalists
lay great stress), the drooping tail, and scared look of the wolf. In
disposition the Esquimaux dogs differ little from wolves, and, according to
Dr. Hayes, they are capable of no attachment to man, and are so savage,
that {22} when hungry they will attack even their masters. According to
Kane they readily become feral. Their affinity is so close with wolves that
they frequently cross with them, and the Indians take the whelps of wolves
"to improve the breed of their dogs." The half-bred wolves sometimes
(Lamare-Picquot) cannot be tamed, "though this case is rare;" but they do
not become thoroughly well broken in till the second or third generation.
These facts show that there can be but little, if any, sterility between
the Esquimaux dog and the wolf, for otherwise they would not be used to
improve the breed. As Dr. Hayes says of these dogs, "reclaimed wolves they
doubtless are."[18]
North America is inhabited by a second kind of wolf, the prairie-wolf
(_Canis latrans_), which is now looked at by all naturalists as
specifically distinct from the common wolf; and is, according to Mr. J. K.
Lord, in some respects intermediate in habits between a wolf and a fox. Sir
J. Richardson, after describing the Hare Indian dog, which differs in many
respects from the Esquimaux dog, says, "It bears the same relation to the
prairie wolf that the Esquimaux dog does to the great grey wolf." He could,
in fact, detect no marked difference between them; and Messrs. Nott and
Gliddon give additional details showing their close resemblance. The dogs
derived from the above two aboriginal sources cross together and with the
wild wolves, at least with the _C. occidentalis_, and with European dogs.
In Florida, according to Bartram, the black wolf-dog of the Indians differs
in nothing from the wolves of that country except in barking.[19]
{23}
Turning to the southern parts of the New World, Columbus found two kinds of
dogs in the West Indies; and Fernandez[20] describes three in Mexico: some
of these native dogs were dumb--that is, did not bark. In Guiana it has
been known since the time of Buffon that the natives cross their dogs with
an aboriginal species, apparently the _Canis cancrivorus_. Sir R.
Schomburgk, who has so carefully explored these regions, writes to me, "I
have been repeatedly told by the Arawaak Indians, who reside near the
coast, that they cross their dogs with a wild species to improve the breed,
and individual dogs have been shown to me which certainly resembled the _C.
cancrivorus_ much more than the common breed. It is but seldom that the
Indians keep the _C. cancrivorus_ for domestic purposes, nor is the Ai,
another species of wild dog, and which I consider to be identical with the
_Dusicyon silvestris_ of H. Smith, now much used by the Arecunas for the
purpose of hunting. The dogs of the Taruma Indians are quite distinct, and
resemble Buffon's St. Domingo greyhound." It thus appears that the natives
of Guiana have partially domesticated two aboriginal species, and still
cross their dogs with them; these two species belong to a quite different
type from the North American and European wolves. A careful observer,
Rengger,[21] gives reasons for believing that a hairless dog was
domesticated when America was first visited by Europeans: some of these
dogs in Paraguay are still dumb, and Tschudi[22] states that they suffer
from cold in the Cordillera. This naked dog is, however, quite distinct
from that found preserved in the ancient Peruvian burial-places, and
described by Tschudi, under the name of _Canis Ingae_, as withstanding cold
well and as barking. It is not known whether these two distinct kinds of
dog are the descendants of native species, and it might be argued that when
man first migrated into America he brought with him from the Asiatic
continent dogs {24} which had not learned to bark; but this view does not
seem probable, as the natives along the line of their march from the north
reclaimed, as we have seen, at least two N. American species of Canidae.
Turning to the Old World, some European dogs closely resemble the wolf;
thus the shepherd dog of the plains of Hungary is white or reddish-brown,
has a sharp nose, short, erect ears, shaggy coat, and bushy tail, and so
much resembles a wolf that Mr. Paget, who gives this description, says he
has known a Hungarian mistake a wolf for one of his own dogs. Jeitteles,
also, remarks on the close similarity of the Hungarian dog and wolf.
Shepherd dogs in Italy must anciently have closely resembled wolves, for
Columella (vii. 12) advises that white dogs be kept, adding, "pastor album
probat, ne pro lupo canem feriat." Several accounts have been given of dogs
and wolves crossing naturally; and Pliny asserts that the Gauls tied their
female dogs in the woods that they might cross with wolves.[23] The
European wolf differs slightly from that of North America, and has been
ranked by many naturalists as a distinct species. The common wolf of India
is also by some esteemed as a third species, and here again we find a
marked resemblance between the pariah dogs of certain districts of India
and the Indian wolf.[24]
With respect to Jackals, Isidore Geoffroy Saint Hilaire[25] says that not
one constant difference can be pointed out between their structure and that
of the smaller races of dogs. They agree closely in habits: jackals, when
tamed and called by their {25} master, wag their tails, crouch, and throw
themselves on their backs; they smell at the tails of dogs, and void their
urine sideways.[26] A number of excellent naturalists, from the time of
Gueldenstaedt to that of Ehrenberg, Hemprich, and Cretzschmar, have expressed
themselves in the strongest terms with respect to the resemblance of the
half-domestic dogs of Asia and Egypt to jackals. M. Nordmann, for instance,
says, "Les chiens d'Awhasie ressemblent etonnamment a des chacals."
Ehrenberg[27] asserts that the domestic dogs of Lower Egypt, and certain
mummied dogs, have for their wild type a species of wolf (_C. lupaster_) of
the country; whereas the domestic dogs of Nubia and certain other mummied
dogs have the closest relation to a wild species of the same country, viz.
_C. sabbar_, which is only a form of the common jackal. Pallas asserts that
jackals and dogs sometimes naturally cross in the East; and a case is on
record in Algeria.[28] The greater number of naturalists divide the jackals
of Asia and Africa into several species, but some few rank them all as one.
I may add that the domestic dogs on the coast of Guinea are fox-like
animals, and are dumb.[29] On the east coast of Africa, between lat. 4 deg. and
6 deg. south, and about ten days' journey in the interior, a semi-domestic dog,
as the Rev. S. Erhardt informs me, is kept, which the natives assert is
derived from a similar wild animal. Lichtenstein[30] says that the dogs of
the Bosjemans present a striking resemblance even in colour (excepting the
black stripe down the back) with the _C. mesomelas_ of South Africa. Mr. E.
Layard informs me that he has seen a Caffre dog which closely resembled an
Esquimaux dog. In Australia the Dingo is both domesticated and wild; though
this animal may have been introduced aboriginally by man, yet it must be
considered as almost an endemic form, for its remains have been found in a
similar state of preservation and associated with {26} extinct mammals, so
that its introduction must have been ancient.[31]
From this resemblance in several countries of the half-domesticated dogs to
the wild species still living there,--from the facility with which they can
often be crossed together,--from even half-tamed animals being so much
valued by savages,--and from the other circumstances previously remarked on
which favour their domestication, it is highly probable that the domestic
dogs of the world have descended from two good species of wolf (viz. _C.
lupus_ and _C. latrans_), and from two or three other doubtful species of
wolves (namely, the European, Indian, and North African forms); from at
least one or two South American canine species; from several races or
species of the jackal; and perhaps from one or more extinct species. Those
authors who attribute great influence to the action of climate by itself
may thus account for the resemblance of the domesticated dogs and native
animals in the same countries; but I know of no facts supporting the belief
in so powerful an action of climate.
It cannot be objected to the view of several canine species having been
anciently domesticated, that these animals are tamed with difficulty: facts
have been already given on this head, but I may add that the young of the
_Canis primaevus_ of India were tamed by Mr. Hodgson,[32] and became as
sensible to caresses, and manifested as much intelligence, as any sporting
dog of the same age. There is not much difference, as we have already shown
and shall immediately further see, in habits between the domestic dogs of
the North American Indians and the wolves of that country, or between the
Eastern pariah dogs and jackals, or between the dogs which have run wild in
various countries and the several natural species of the family. The habit
of barking, however, which is almost universal with domesticated {27} dogs,
and which does not characterise a single natural species of the family,
seems an exception; but this habit is soon lost and soon reacquired. The
case of the wild dogs on the island of Juan Fernandez having become dumb
has often been quoted, and there is reason to believe[33] that the dumbness
ensued in the course of thirty-three years; on the other hand, dogs taken
from this island by Ulloa slowly reacquired the habit of barking. The
Mackenzie-river dogs, of the _Canis latrans_ type, when brought to England,
never learned to bark properly; but one born in the Zoological Gardens[34]
"made his voice sound as loudly as any other dog of the same age and size."
According to Professor Nillson,[35] a wolf-whelp reared by a bitch barks.
I. Geoffroy Saint Hilaire exhibited a jackal which barked with the same
tone as any common dog.[36] An interesting account has been given by Mr. G.
Clarke[37] of some dogs run wild on Juan de Nova, in the Indian Ocean;
"they had entirely lost the faculty of barking; they had no inclination for
the company of other dogs, nor did they acquire their voice," during a
captivity of several months. On the island they "congregate in vast packs,
and catch sea-birds with as much address as foxes could display." The feral
dogs of La Plata have not become dumb; they are of large size, hunt single
or in packs, and burrow holes for their young.[38] In these habits the
feral dogs of La Plata resemble wolves and jackals; both of which hunt
either singly or in packs, and burrow holes.[39] These feral dogs have not
become uniform in colour on Juan Fernandez, Juan de Nova, or La Plata.[40]
In Cuba the feral dogs are described by Poeppig as nearly all
mouse-coloured, with short ears and light-blue eyes. {28} In St. Domingo,
Col. Ham. Smith says[41] that the feral dogs are very large, like
greyhounds, of a uniform pale blue-ash, with small ears, and large
light-brown eyes. Even the wild Dingo, though so anciently naturalised in
Australia, "varies considerably in colour," as I am informed by Mr. P. P.
King: a half-bred Dingo reared in England[42] showed signs of wishing to
burrow.
From the several foregoing facts we see that reversion in the feral
state gives no indication of the colour or size of the aboriginal
parent-species. One fact, however, with respect to the colouring of
domestic dogs, I at one time hoped might have thrown some light on
their origin; and it is worth giving, as showing how colouring follows
laws, even in so anciently and thoroughly domesticated an animal as the
dog. Black dogs with tan-coloured feet, whatever breed they may belong
to, almost invariably have a tan-coloured spot on the upper and inner
corners of each eye, and their lips are generally thus coloured. I have
seen only two exceptions to this rule, namely, in a spaniel and
terrier. Dogs of a light-brown colour often have a lighter,
yellowish-brown spot over the eyes; sometimes the spot is white, and in
a mongrel terrier the spot was black. Mr. Waring kindly examined for me
a stud of fifteen greyhounds in Suffolk: eleven of them were black, or
black and white, or brindled, and these had no eye-spots; but three
were red and one slaty-blue, and these four had dark-coloured spots
over their eyes. Although the spots thus sometimes differ in colour,
they strongly tend to be tan-coloured; this is proved by my having seen
four spaniels, a setter, two Yorkshire shepherd dogs, a large mongrel,
and some fox-hounds, coloured black and white, with not a trace of
tan-colour, excepting the spots over the eyes, and sometimes a little
on the feet. These latter cases, and many others, show plainly that the
colour of the feet and the eye-spots are in some way correlated. I have
noticed, in various breeds, every gradation, from the whole face being
tan-coloured, to a complete ring round the eyes, to a minute spot over
the inner and upper corners. The spots occur in various sub-breeds of
terriers and spaniels; in setters; in hounds of various kinds,
including the turnspit-like German badger-hound; in shepherd dogs; in a
mongrel, of which neither parent had the spots; in one pure bulldog,
though the spots were in this case almost white; and in
greyhounds,--but true black-and-tan greyhounds are excessively rare;
nevertheless I have been assured by Mr. Warwick, that one ran at the
Caledonian Champion meeting of April, 1860, and was "marked precisely
like a black-and-tan terrier." Mr. Swinhoe at my request looked at the
dogs in China, at Amoy, and he soon noticed a brown dog with yellow
spots over the eyes. Colonel H. Smith[43] figures the magnificent black
mastiff of Thibet with a {29} tan-coloured stripe over the eyes, feet,
and chaps; and what is more singular, he figures the Alco, or native
domestic dog of Mexico, as black and white, with narrow tan-coloured
rings round the eyes; at the Exhibition of dogs in London, May, 1863, a
so-called forest-dog from North-West Mexico was shown, which had pale
tan-coloured spots over the eyes. The occurrence of these tan-coloured
spots in dogs of such extremely different breeds, living in various
parts of the world, makes the fact highly remarkable.
We shall hereafter see, especially in the chapter on Pigeons, that
coloured marks are strongly inherited, and that they often aid us in
discovering the primitive forms of our domestic races. Hence, if any
wild canine species had distinctly exhibited the tan-coloured spots
over the eyes, it might have been argued that this was the parent-form
of nearly all our domestic races. But after looking at many coloured
plates, and through the whole collection of skins in the British
Museum, I can find no species thus marked. It is no doubt possible that
some extinct species was thus coloured. On the other hand, in looking
at the various species, there seems to be a tolerably plain correlation
between tan-coloured legs and face; and less frequently between black
legs and a black face; and this general rule of colouring explains to a
certain extent the above-given cases of correlation between the
eye-spots and the colour of the feet. Moreover, some jackals and foxes
have a trace of a white ring round their eyes, as in _C. mesomelas_,
_C. aureus_, and (judging from Colonel Ham. Smith's drawing) in _C.
alopex_ and _C. thaleb_. Other species have a trace of a black line
over the corners of the eyes, as in _C. variegatus_,
_cinereo-variegatus_, and _fulvus_, and the wild Dingo. Hence I am
inclined to conclude that a tendency for tan-coloured spots to appear
over the eyes in the various breeds of dogs, is analogous to the case
observed by Desmarest, namely, that when any white appears on a dog the
tip of the tail is always white, "de maniere a rappeler la tacho
terminale de meme couleur, qui caracterise la plupart des Canidees
sauvages."[44]
It has been objected that our domestic dogs cannot be descended from wolves
or jackals, because their periods of gestation are different. The supposed
difference rests on statements made by Buffon, Gilibert, Bechstein, and
others; but these are now known to be erroneous; and the period is found to
agree in the wolf, jackal, and dog, as closely as could be expected, for it
is often in some degree variable.[45] Tessier, who {30} has closely
attended to this subject, allows a difference of four days in the gestation
of the dog. The Rev. W. D. Fox has given me three carefully recorded cases
of retrievers, in which the bitch was put only once to the dog; and not
counting this day, but counting that of parturition, the periods were
fifty-nine, sixty-two, and sixty-seven days. The average period is
sixty-three days; but Bellingeri states that this holds good only with
large dogs; and that for small races it is from sixty to sixty-three days;
Mr. Eyton of Eyton, who has had much experience with dogs, also informs me
that the time is apt to be longer with large than with small dogs.
F. Cuvier has objected that the jackal would not have been domesticated on
account of its offensive smell; but savages are not sensitive in this
respect. The degree of odour, also, differs in the different kinds of
jackal;[46] and Colonel H. Smith makes a sectional division of the group
with one character dependent on not being offensive. On the other hand,
dogs--for instance, rough and smooth terriers--differ much in this respect;
and M. Godron states that the hairless so-called Turkish dog is more
odoriferous than other dogs. Isidore Geoffroy[47] gave to a dog the same
odour as that from a jackal by feeding it on raw flesh.
The belief that our dogs are descended from wolves, jackals, South American
Canidae, and other species, suggests a far more important difficulty. These
animals in their undomesticated state, judging from a widely-spread
analogy, would have been in some degree sterile if intercrossed; and such
sterility will be admitted as almost certain by all those who believe that
the lessened fertility of crossed forms is an infallible criterion of
specific distinctness. Anyhow these animals keep distinct in the countries
which they inhabit in common. On the other hand, all domestic dogs, which
are here supposed to be descended {31} from several distinct species, are,
as far as is known, mutually fertile together. But, as Broca has well
remarked,[48] the fertility of successive generations of mongrel dogs has
never been scrutinised with that care which is thought indispensable when
species are crossed. The few facts leading to the conclusion that the
sexual feelings and reproductive powers differ in the several races of the
dog when crossed are (passing over mere size as rendering propagation
difficult) as follows: the Mexican Alco[49] apparently dislikes dogs of
other kinds, but this perhaps is not strictly a sexual feeling; the
hairless endemic dog of Paraguay, according to Rengger, mixes less with the
European races than these do with each other; the Spitz-dog in Germany is
said to receive the fox more readily than do other breeds; and Dr. Hodgkin
states that a female Dingo in England attracted the male wild foxes. If
these latter statements can be trusted, they prove some degree of sexual
difference in the breeds of the dog. But the fact remains that our domestic
dogs, differing so widely as they do in external structure, are far more
fertile together than we have reason to believe their supposed wild parents
would have been. Pallas assumes[50] that a long course of domestication
eliminates that sterility which the parent-species would have exhibited if
only lately captured; no distinct facts are recorded in support of this
hypothesis; but the evidence seems to me so strong (independently of the
evidence derived from other domesticated animals) in favour of our domestic
dogs having descended from several wild stocks, that I am led to admit the
truth of this hypothesis.
There is another and closely allied difficulty consequent on the doctrine
of the descent of our domestic dogs from several wild species, namely, that
they do not seem to be perfectly fertile with their supposed parents. But
the experiment has not been quite fairly tried; the Hungarian dog, for
instance, {32} which in external appearance so closely resembles the
European wolf, ought to be crossed with this wolf; and the pariah-dogs of
India with Indian wolves and jackals; and so in other cases. That the
sterility is very slight between certain dogs and wolves and other Canidae
is shown by savages taking the trouble to cross them. Buffon got four
successive generations from the wolf and dog, and the mongrels were
perfectly fertile together.[51] But more lately M. Flourens states
positively as the result of his numerous experiments that hybrids from the
wolf and dog, crossed _inter se_, become sterile at the third generation,
and those from the jackal and dog at the fourth generation.[52] But these
animals were closely confined; and many wild animals, as we shall see in a
future chapter, are rendered by confinement in some degree or even utterly
sterile. The Dingo, which breeds freely in Australia with our imported
dogs, would not breed though repeatedly crossed in the Jardin des
Plantes.[53] Some hounds from Central Africa, brought home by Major Denham,
never bred in the Tower of London;[54] and a similar tendency to sterility
might be transmitted to the hybrid offspring of a wild animal. Moreover, it
appears that in M. Flourens' experiments the hybrids were closely bred in
and in for three or four generations; but this circumstance, although it
would almost certainly increase the tendency to sterility, would hardly
account for the final result, even though aided by close confinement,
unless there had been some original tendency to lessened fertility. Several
years ago I saw confined in the Zoological Gardens of London a female
hybrid from an English dog and jackal, which even in this the first
generation was so sterile that, as I was assured by {33} her keeper, she
did not fully exhibit her proper periods; but this case, from the numerous
instances of fertile hybrids from these two animals, was certainly
exceptional. In almost all experiments on the crossing of animals there are
so many causes of doubt, that it is extremely difficult to come to any
positive conclusion. It would, however, appear, that those who believe that
our dogs are descended from several species will have not only to admit
that their offspring after a long course of domestication generally lose
all tendency to sterility when crossed together; but that between certain
breeds of dogs and some of their supposed aboriginal parents a certain
degree of sterility has been retained or possibly even acquired.
Notwithstanding the difficulties in regard to fertility given in the last
two paragraphs, when we reflect on the inherent improbability of man having
domesticated throughout the world one single species alone of so widely
distributed, so easily tamed, and so useful a group as the Canidae; when we
reflect on the extreme antiquity of the different breeds; and especially
when we reflect on the close similarity, both in external structure and
habits, between the domestic dogs of various countries and the wild species
still inhabiting these same countries, the balance of evidence is strongly
in favour of the multiple origin of our dogs.
* * * * *
_Differences between the several Breeds of the Dog._--If the several breeds
have descended from several wild stocks, their difference can obviously in
part be explained by that of their parent-species. For instance, the form
of the greyhound may be partly accounted for by descent from some such
animal as the slim Abyssinian _Canis simensis_,[55] with its elongated
muzzle; that of the larger dogs from the larger wolves, and the smaller and
slighter dogs from jackals: and thus perhaps we may account for certain
constitutional and climatal differences. But it would be a great error to
suppose that there has not been in addition[56] a large amount of
variation. The intercrossing of the several aboriginal wild stocks, and of
the subsequently formed {34} races, has probably increased the total number
of breeds, and, as we shall presently see, has greatly modified some of
them. But we cannot explain by crossing the origin of such extreme forms as
thoroughbred greyhounds, bloodhounds, bulldogs, Blenheim spaniels,
terriers, pugs, &c., unless we believe that forms equally or more strongly
characterised in these different respects once existed in nature. But
hardly any one has been bold enough to suppose that such unnatural forms
ever did or could exist in a wild state. When compared with all known
members of the family of Canidae they betray a distinct and abnormal origin.
No instance is on record of such dogs as bloodhounds, spaniels, true
greyhounds having been kept by savages: they are the product of
long-continued civilization.
The number of breeds and sub-breeds of the dog is great: Youatt, for
instance, describes twelve kinds of greyhounds. I will not attempt to
enumerate or describe the varieties, for we cannot discriminate how
much of their difference is due to variation, and how much to descent
from different aboriginal stocks. But it may be worth while briefly to
mention some points. Commencing with the skull, Cuvier has admitted[57]
that in form the differences are "plus fortes que celles d'aucunes
especes sauvages d'un meme genre naturel." The proportions of the
different bones; the curvature of the lower jaw, the position of the
condyles with respect to the plane of the teeth (on which F. Cuvier
founded his classification), and in mastiffs the shape of its posterior
branch; the shape of the zygomatic arch, and of the temporal fossae; the
position of the occiput--all vary considerably.[58] The dog has
properly six pairs of molar teeth in the upper jaw, and seven in the
lower; but several naturalists have seen not rarely an additional pair
in the upper jaw;[59] and Professor Gervais says that there are dogs
"qui ont sept paires de dents superieures et huit inferieures.". De
Blainville[60] has given full particulars on the frequency of these
deviations in the number of the teeth, and has shown that it is not
always the same tooth which is supernumerary. In short-muzzled races,
according to H. Mueller,[61] the molar teeth stand obliquely, whilst in
long-muzzled races they are placed longitudinally, with open spaces
between them. The naked, so-called Egyptian or Turkish dog is extremely
deficient in its {35} teeth,[62]--sometimes having none except one
molar on each side; but this, though characteristic of the breed, must
be considered as a monstrosity. M. Girard,[63] who seems to have
attended closely to the subject, says that the period of the appearance
of the permanent teeth differs in different dogs, being earlier in
large dogs; thus the mastiff assumes its adult teeth in four or five
months, whilst in the spaniel the period is sometimes more than seven
or eight months.
With respect to minor differences little need be said. Isidore Geoffroy
has shown[64] that in size some dogs are six times as long (the tail
being excluded) as others; and that the height relatively to the length
of the body varies from between one to two, and one to nearly four. In
the Scotch deer-hound there is a striking and remarkable difference in
the size of the male and female.[65] Every one knows how the ears vary
in size in different breeds, and with their great development their
muscles become atrophied. Certain breeds of dogs are described as
having a deep furrow between the nostrils and lips. The caudal
vertebrae, according to F. Cuvier, on whose authority the two last
statements rest, vary in number; and the tail in shepherd dogs is
almost absent. The mammae vary from seven to ten in number; Daubenton,
having examined twenty-one dogs, found eight with five mammae on each
side; eight with four on each side; and the others with an unequal
number on the two sides.[66] Dogs have properly five toes in front and
four behind, but a fifth toe is often added; and F. Cuvier states that,
when a fifth toe is present, a fourth cuneiform bone is developed; and,
in this case, sometimes the great cuneiform bone is raised, and gives
on its inner side a large articular surface to the astragalus; so that
even the relative connection of the bones, the most constant of all
characters, varies. These modifications, however, in the feet of dogs
are not important, because they ought to be ranked, as De Blainville
has shown,[67] as monstrosities. Nevertheless they are interesting from
being correlated with the size of the body, for they occur much more
frequently with mastiffs and other large breeds than with small dogs.
Closely allied varieties, however, sometimes differ in this respect;
thus Mr. Hodgson states that the black-and-tan Lassa variety of the
Thibet mastiff has the fifth digit, whilst the Mustang sub-variety is
not thus characterised. The extent to which the skin is developed
between the toes varies much; but we shall return to this point. The
degree to which the various breeds differ in the perfection of their
senses, dispositions, and inherited habits is notorious to every one.
The breeds present some constitutional differences: the pulse, says
Youatt,[68] "varies materially according to the breed, as well {36} as
to the size of the animal." Different breeds of dogs are subject in
different degrees to various diseases. They certainly become adapted to
different climates under which they have long existed. It is notorious
that most of our best European breeds deteriorate in India.[69] The
Rev. R. Everest[70] believes that no one has succeeded in keeping the
Newfoundland dog long alive in India; so it is, according to
Lichtenstein,[71] even at the Cape of Good Hope. The Thibet mastiff
degenerates on the plains of India, and can live only on the
mountains.[72] Lloyd[73] asserts that our bloodhounds and bulldogs have
been tried, and cannot withstand the cold of the northern European
forests.
Seeing in how many characters the races of the dog differ from each other,
and remembering Cuvier's admission that their skulls differ more than do
those of the species of any natural genus, and bearing in mind how closely
the bones of wolves, jackals, foxes, and other Canidae agree, it is
remarkable that we meet with the statement, repeated over and over again,
that the races of the dog differ in no important characters. A highly
competent judge, Prof. Gervais,[74] admits, "si l'on prenait sans controle
les alterations dont chacun de ces organes est susceptible, on pourrait
croire qu'il y a entre les chiens domestiques des differences plus grandes
que celles qui separent ailleurs les especes, quelquefois meme les genres."
Some of the differences above enumerated are in one respect of
comparatively little value, for they are not characteristic of distinct
breeds: no one pretends that such is the case with the additional molar
teeth or with the number of mammae; the additional digit is generally
present with mastiffs, and some of the more important differences in the
skull and lower jaw are more or less characteristic of various breeds. But
we must not forget that the predominant power of selection has not been
applied in any of these cases; we have variability in important parts, but
the differences have not been fixed by selection. Man {37} cares for the
form and fleetness of his greyhounds, for the size of his mastiffs, for the
strength of the jaw in his bulldogs, &c.; but he cares nothing about the
number of their molar teeth or mammae or digits; nor do we know that
differences in these organs are correlated with, or owe their development
to, differences in other parts of the body about which man does care. Those
who have attended to the subject of selection will admit that, nature
having given variability, man, if he so chose, could fix five toes to the
hinder feet of certain breeds of dogs, as certainly as to the feet of his
Dorking-fowls: he could probably fix, but with much more difficulty, an
additional pair of molar teeth in either jaw, in the same way as he has
given additional horns to certain breeds of sheep; if he wished to produce
a toothless breed of dogs, having the so-called Turkish dog with its
imperfect teeth to work on, he could probably do so, for he has succeeded
in making hornless breeds of cattle and sheep.
With respect to the precise causes and steps by which the several races of
dogs have come to differ so greatly from each other, we are, as in most
other cases, profoundly ignorant. We may attribute part of the difference
in external form and constitution to inheritance from distinct wild stocks,
that is to changes effected under nature before domestication. We must
attribute something to the crossing of the several domestic and natural
races. I shall, however, soon recur to the crossing of races. We have
already seen how often savages cross their dogs with wild native species;
and Pennant gives a curious account[75] of the manner in which Fochabers,
in Scotland, was stocked "with a multitude of curs of a most wolfish
aspect" from a single hybrid-wolf brought into that district.
It would appear that climate to a certain extent directly modifies the
forms of dogs. We have lately seen that several of our English breeds
cannot live in India, and it is positively asserted that when bred there
for a few generations they degenerate not only in their mental faculties,
but in form. Captain Williamson,[76] who carefully attended to this
subject, states that "hounds are the most rapid in their decline;"
"greyhounds and {38} pointers, also, rapidly decline." But spaniels, after
eight or nine generations, and without a cross from Europe, are as good as
their ancestors. Dr. Falconer informs me that bulldogs, which have been
known, when first brought into the country, to pin down even an elephant by
its trunk, not only fall off after two of three generations in pluck and
ferocity, but lose the under-hung character of their lower jaws; their
muzzles become finer and their bodies lighter. English dogs imported into
India are so valuable that probably due care has been taken to prevent
their crossing with native dogs; so that the deterioration cannot be thus
accounted for. The Rev. R. Everest informs me that he obtained a pair of
setters, born in India, which perfectly resembled their Scotch parents: he
raised several litters from them in Delhi, taking the most stringent
precautions to prevent a cross, but he never succeeded, though this was
only the second generation in India, in obtaining a single young dog like
its parents in size or make; their nostrils were more contracted, their
noses more pointed, their size inferior, and their limbs more slender. This
remarkable tendency to rapid deterioration in European dogs subjected to
the climate of India, may perhaps partly be accounted for by the tendency
to reversion to a primordial condition which many animals exhibit, as we
shall see in a future chapter, when exposed to new conditions of life.
Some of the peculiarities characteristic of the several breeds of the dog
have probably arisen suddenly, and, though strictly inherited, may be
called monstrosities; for instance, the shape of the legs and body in the
turnspit of Europe and India; the shape of the head and the under-hanging
jaw in the bull and pug-dog, so alike in this one respect and so unlike in
all others. A peculiarity suddenly arising, and therefore in one sense
deserving to be called a monstrosity, may, however, be increased and fixed
by man's selection. We can hardly doubt that long-continued training, as
with the greyhound in coursing hares, as with water-dogs in swimming--and
the want of exercise, in the case of lapdogs--must have produced some
direct effect on their structure and instincts. But we shall immediately
see that the most potent cause of change has probably been the selection,
both methodical and unconscious, of slight individual differences,--the
{39} latter kind of selection resulting from the occasional preservation,
during hundreds of generations, of those individual dogs which were the
most useful to man for certain purposes and under certain conditions of
life. In a future chapter on Selection I shall show that even barbarians
attend closely to the qualities of their dogs. This unconscious selection
by man would lie aided by a kind of natural selection; for the dogs of
savages have partly to gain their own subsistence; for instance, in
Australia, as we hear from Mr. Nind,[77] the dogs are sometimes compelled
by want to leave their masters and provide for themselves; but in a few
days they generally return. And we may infer that dogs of different shapes,
sizes, and habits, would have best chance of surviving under different
circumstances,--on open, sterile plains, where they have to run down their
own prey,--on rocky coasts, where they have to feed on crabs and fish left
in the tidal pools, as in the case of New Guinea and Tierra del Fuego. In
this latter country, as I am informed by Mr. Bridges, the Catechist to the
Mission, the dogs turn over the stones on the shore to catch the
crustaceans which lie beneath, and they "are clever enough to knock off the
shell-fish at a first blow;" for if this be not done, shell-fish are well
known to have an almost invincible power of adhesion.
It has already been remarked that dogs differ in the degree to which their
feet are webbed. In dogs of the Newfoundland breed, which are eminently
aquatic in their habits, the skin, according to Isidore Geoffroy,[78]
extends to the third phalanges, whilst in ordinary dogs it extends only to
the second. In two Newfoundland dogs which I examined, when the toes were
stretched apart and viewed on the under side, the skin extended in a nearly
straight line between the outer margins of the balls of the toes; whereas,
in two terriers of distinct sub-breeds, the skin viewed in the same manner
was deeply scooped out. In Canada there is a dog which is peculiar to the
country and common there, and this has "half-webbed feet and is fond of the
water."[79] English otter-hounds are said to have webbed feet: a friend
examined for me the feet of two, in comparison {40} with the feet of some
harriers and bloodhounds; he found the skin variable in extent in all, but
more developed in the otter than in the other hounds.[80] As aquatic
animals which belong to quite different orders have webbed feet, there can
be no doubt that this structure would be serviceable to dogs that frequent
the water. We may confidently infer that no man ever selected his
water-dogs by the extent to which the skin was developed between their
toes; but what he does, is to preserve and breed from those individuals
which hunt best in the water, or best retrieve wounded game, and thus he
unconsciously selects dogs with feet slightly better webbed. Man thus
closely imitates Natural Selection. We have an excellent illustration of
this same process in North America, where, according to Sir J.
Richardson,[81] all the wolves, foxes, and aboriginal domestic dogs have
their feet broader than in the corresponding species of the Old World, and
"well calculated for running on the snow." Now, in these Arctic regions,
the life or death of every animal will often depend on its success in
hunting over the snow when softened; and this will in part depend on the
feet being broad; yet they must not be so broad as to interfere with the
activity of the animal when the ground is sticky, or with its power of
burrowing holes, or with other habits of life.
As changes in domestic breeds which take place so slowly as not to be
noticed at any one period, whether due to the selection of individual
variations or of differences resulting from crosses, are most important in
understanding the origin of our domestic productions, and likewise in
throwing indirect light on the changes effected under nature, I will give
in detail such cases as I have been able to collect. Lawrence,[82] who paid
particular attention to the history of the foxhound, writing in 1829, says
that between eighty and ninety years before "an entirely new foxhound was
raised through the breeder's art," the ears of the old southern hound being
reduced, the bone and bulk lightened, the waist increased in length, and
the stature {41} somewhat added to. It is believed that this was effected
by a cross with the greyhound. With respect to this latter dog, Youatt,[83]
who is generally cautious in his statements, says that the greyhound within
the last fifty years, that is before the commencement of the present
century, "assumed a somewhat different character from that which he once
possessed. He is now distinguished by a beautiful symmetry of form, of
which he could not once boast, and he has even superior speed to that which
he formerly exhibited. He is no longer used to struggle with deer, but
contends with his fellows over a shorter and speedier course." An able
writer[84] believes that our English greyhounds are the descendants,
_progressively improved_, of the large rough greyhounds which existed in
Scotland so early as the third century. A cross at some former period with
the Italian greyhound has been suspected; but this seems hardly probable,
considering the feebleness of this latter breed. Lord Orford, as is well
known, crossed his famous greyhounds, which failed in courage, with a
bulldog--this breed being-chosen from being deficient in the power of
scent; "after the sixth or seventh generation," says Youatt, "there was not
a vestige left of the form of the bulldog, but his courage and indomitable
perseverance remained."
Youatt infers, from a comparison of an old picture of King Charles's
spaniels with the living dog, that "the breed of the present day is
materially altered for the worse:" the muzzle has become shorter, the
forehead more prominent, and the eyes larger: the changes in this case have
probably been due to simple selection. The setter, as this author remarks
in another place, "is evidently the large spaniel improved to his present
peculiar size and beauty, and taught another way of marking his game. If
the form of the dog were not sufficiently satisfactory on this point, we
might have recourse to history:" he then refers to a document dated 1685
bearing on this subject, and adds that the pure Irish setter shows no signs
of a cross with the pointer, which some authors suspect has been the case
with the English setter. Another writer[85] remarks {42} that, if the
mastiff and English bulldog had formerly been as distinct as they are at
the present time (_i.e._ 1828), so accurate an observer as the poet Gay
(who was the author of 'Rural Sports' in 1711) would have spoken in his
Fable of the _Bull and the Bulldog_, and not of the _Bull and the Mastiff_.
There can be no doubt that the fancy bulldogs of the present day, now that
they are not used for bull-baiting, have become greatly reduced in size,
without any express intention on the part of the breeder. Our pointers are
certainly descended from a Spanish breed, as even their names, Don, Ponto,
Carlos, &c., would show: it is said that they were not known in England
before the Revolution in 1688;[86] but the breed since its introduction has
been much modified, for Mr. Borrow, who is a sportsman and knows Spain
intimately well, informs me that he has not seen in that country any breed
"corresponding in figure with the English pointer; but there are genuine
pointers near Xeres which have been imported by English gentlemen." A
nearly parallel case is offered by the Newfoundland dog, which was
certainly brought into England from that country, but which has since been
so much modified that, as several writers have observed, it does not now
closely resemble any existing native dog in Newfoundland.[87]
These several cases of slow and gradual changes in our English dogs possess
some interest; for though the changes have generally, but not invariably,
been caused by one or two crosses with a distinct breed, yet we may feel
sure, from the well-known extreme variability of crossed breeds, that
rigorous and long-continued selection must have been practised, in order to
improve them in a definite manner. As soon as any strain or family became
slightly improved or better adapted to altered circumstances, it would tend
to supplant the older and less improved strains. For instance, as soon as
the old foxhound was improved by a cross with the greyhound, or by simple
selection, and assumed its present character--and the change was probably
required by {43} the increased fleetness of our hunters--it rapidly spread
throughout the country, and is now everywhere nearly uniform. But the
process of improvement is still going on, for every one tries to improve
his strain by occasionally procuring dogs from the best kennels. Through
this process of gradual substitution the old English hound has been lost;
and so it has been with the old Irish greyhound and apparently with the old
English bulldog. But the extinction of former breeds is apparently aided by
another cause; for whenever a breed is kept in scanty numbers, as at
present with the bloodhound, it is reared with difficulty, and this
apparently is due to the evil effects of long-continued close
interbreeding. As several breeds of the dog have been slightly but sensibly
modified within so short a period as the last one or two centuries, by the
selection of the best individual dogs, modified in many cases by crosses
with other breeds; and as we shall hereafter see that the breeding of dogs
was attended to in ancient times, as it still is by savages, we may
conclude that we have in selection, even if only occasionally practised, a
potent means of modification.
DOMESTIC CATS.
Cats have been domesticated in the East from an ancient period; Mr. Blyth
informs me that they are mentioned in a Sanskrit writing 2000 years old,
and in Egypt their antiquity is known to be even greater, as shown by
monumental drawings and their mummied bodies. These mummies, according to
De Blainville[88] who has particularly studied the subject, belong to no
less than three species, namely, _F. caligulata_, _bubastes_, and _chaus_.
The two former species are said to be still found, both wild and
domesticated, in parts of Egypt. _F. caligulata_ presents a difference in
the first inferior milk molar tooth, as compared with the domestic cats of
Europe, which makes De Blainville conclude that it is not one of the
parent-forms of our cats. Several naturalists, as Pallas, Temminck, Blyth,
believe that domestic cats are the descendants of several species {44}
commingled: it is certain that cats cross readily with various wild
species, and it would appear that the character of the domestic breeds has,
at least in some cases, been thus affected. Sir W. Jardine has no doubt
that, "in the north of Scotland, there has been occasional crossing with
our native species (_F. sylvestris_), and that the result of these crosses
has been kept in our houses. I have seen," he adds, "many cats very closely
resembling the wild cat, and one or two that could scarcely be
distinguished from it." Mr. Blyth[89] remarks on this passage, "but such
cats are never seen in the southern parts of England; still, as compared
with any Indian tame cat, the affinity of the ordinary British cat to _F.
sylvestris_ is manifest; and due I suspect to frequent intermixture at a
time when the tame cat was first introduced into Britain and continued
rare, while the wild species was far more abundant than at present." In
Hungary, Jeitteles[90] was assured on trustworthy authority that a wild
male cat crossed with a female domestic cat, and that the hybrids long
lived in a domesticated state. In Algiers the domestic cat has crossed with
the wild cat (_F. Lybica_) of that country.[91] In South Africa, as Mr. E.
Layard informs me, the domestic cat intermingles freely with the wild _F.
caffra_; he has seen a pair of hybrids which were quite tame and
particularly attached to the lady who brought them up; and Mr. Fry has
found that these hybrids are fertile. In India the domestic cat, according
to Mr. Blyth, has crossed with four Indian species. With respect to one of
these species, _F. chaus_, an excellent observer, Sir W. Elliot, informs me
that he once killed, near Madras, a wild brood, which were evidently
hybrids from the domestic cat; these young animals had a thick lynx-like
tail and the broad brown bar on the inside of the forearm characteristic of
_F. chaus_. Sir W. Elliot adds that he has often observed this same mark on
the forearms of domestic cats in India. Mr. Blyth states that domestic cats
coloured nearly like _F. chaus_, but not resembling that species in shape,
abound in {45} Bengal; he adds, "such a colouration is utterly unknown in
European cats, and the proper tabby markings (pale streaks on a black
ground, peculiarly and symmetrically disposed), so common in English cats,
are never seen in those of India." Dr. D. Short has assured Mr. Blyth[92]
that at Hansi hybrids between the common cat and _F. ornata_ (or
_torquata_) occur, "and that many of the domestic cats of that part of
India were undistinguishable from the wild _F. ornata_." Azara states, but
only on the authority of the inhabitants, that in Paraguay the cat has
crossed with two native species. From these several cases we see that in
Europe, Asia, Africa, and America, the common cat, which lives a freer life
than most other domesticated animals, has crossed with various wild
species; and that in some instances the crossing has been sufficiently
frequent to affect the character of the breed.
Whether domestic cats have descended from several distinct species, or have
only been modified by occasional crosses, their fertility, as far as is
known, is unimpaired. The large Angora or Persian cat is the most distinct
in structure and habits of all the domestic breeds; and is believed by
Pallas, but on no distinct evidence, to be descended from the _F. manul_ of
middle Asia; but I am assured by Mr. Blyth that this cat breeds freely with
Indian cats, which, as we have already seen, have apparently been much
crossed with _F. chaus_. In England half-bred Angora cats are perfectly
fertile with the common cat; I do not know whether the half-breeds are
fertile one with another; but as they are common in some parts of Europe,
any marked degree of sterility could hardly fail to have been noticed.
Within the same country we do not meet with distinct races of the cat, as
we do of dogs and of most other domestic animals; though the cats of the
same country present a considerable amount of fluctuating variability. The
explanation obviously is that, from their nocturnal and rambling habits,
indiscriminate crossing cannot without much trouble be prevented. Selection
cannot be brought into play to produce distinct breeds, or to keep those
distinct which have been imported from foreign lands. On the other hand, in
islands and {46} in countries completely separated from each other, we meet
with breeds more or less distinct; and these cases are worth giving as
showing that the scarcity of distinct races in the same country is not
caused by a deficiency of variability in the animal. The tail-less cats of
the Isle of Man are said to differ from common cats not only in the want of
a tail, but in the greater length of their hind legs, in the size of their
heads, and in habits. The Creole cat of Antigua, as I am informed by Mr.
Nicholson, is smaller, and has a more elongated head, than the British cat.
In Ceylon, as Mr. Thwaites writes to me, every one at first notices the
different appearance of the native cat from the English animal; it is of
small size, with closely lying hairs; its head is small, with a receding
forehead; but the ears are large and sharp; altogether it has what is there
called a "low-caste" appearance. Rengger[93] says that the domestic cat,
which has been bred for 300 years in Paraguay, presents a striking
difference from the European cat; it is smaller by a fourth, has a more
lanky body, its hair is short, shining, scanty, and lies close, especially
on the tail: he adds that the change has been less at Ascension, the
capital of Paraguay, owing to the continual crossing with newly imported
cats; and this fact well illustrates the importance of separation. The
conditions of life in Paraguay appear not to be highly favourable to the
cat, for, though they have run half-wild, they do not become thoroughly
feral, like so many other European animals. In another part of South
America, according to Roulin,[94] the introduced cat has lost the habit of
uttering its hideous nocturnal howl. The Rev. W. D. Fox purchased a cat in
Portsmouth, which he was told came from the coast of Guinea; its skin was
black and wrinkled, fur bluish-grey and short, its ears rather bare, legs
long, and whole aspect peculiar. This "negro" cat was fertile with common
cats. On the opposite coast of Africa, at Mombas, Captain Owen, R.N.,[95]
states that all the cats are covered with short stiff hair instead of fur:
he gives a curious account of a cat from Algoa Bay, which had been kept for
some time on board and could be identified with certainty; this {47} animal
was left for only eight weeks at Mombas, but during that short period it
"underwent a complete metamorphosis, having parted with its sandy-coloured
fur." A cat from the Cape of Good Hope has been described by Desmarest as
remarkable from a red stripe extending along the whole length of its back.
Throughout an immense area, namely, the Malayan archipelago, Siam, Pegu,
and Burmah, all the cats have truncated tails about half the proper
length,[96] often with a sort of knot at the end. In the Caroline
archipelago the cats have very long legs, and are of a reddish-yellow
colour.[97] In China a breed has drooping ears. At Tobolsk, according to
Gmelin, there is a red-coloured breed. In Asia, also, we find the
well-known Angora or Persian breed.
The domestic cat has run wild in several countries, and everywhere assumes,
as far as can be judged by the short recorded descriptions, a uniform
character. Near Maldonado, in La Plata, I shot one which seemed perfectly
wild; it was carefully examined by Mr. Waterhouse,[98] who found nothing
remarkable in it, excepting its great size. In New Zealand, according to
Dieffenbach, the feral cats assume a streaky grey colour like that of wild
cats; and this is the case with the half-wild cats of the Scotch Highlands.
We have seen that distant countries possess distinct domestic races of the
cat. The differences may be in part due to descent from several aboriginal
species, or at least to crosses with them. In some cases, as in Paraguay,
Mombas, and Antigua, the differences seem due to the direct action of
different conditions of life. In other cases some slight effect may
possibly be attributed to natural selection, as cats in many cases have
largely to support themselves and to escape diverse dangers. But man, owing
to the difficulty of pairing cats, has done nothing by methodical
selection; and probably very little by unintentional selection; though in
each litter he generally saves the prettiest, {48} and values most a good
breed of mouse or rat-catchers. Those cats which have a strong tendency to
prowl after game, generally get destroyed by traps. As cats are so much
petted, a breed bearing the same relation to other cats, that lapdogs bear
to larger dogs, would have been much valued; and if selection could have
been applied, we should certainly have had many breeds in each
long-civilized country, for there is plenty of variability to work upon.
We see in this country considerable diversity in size, some in the
proportions of the body, and extreme variability in colouring. I have only
lately attended to this subject, but have already heard of some singular
cases of variation; one of a cat born in the West Indies toothless, and
remaining so all its life. Mr. Tegetmeier has shown me the skull of a
female cat with its canines so much developed that they protruded uncovered
beyond the lips; the tooth with the fang being .95, and the part projecting
from the gum .6 of an inch in length. I have heard of a family of six-toed
cats. The tail varies greatly in length; I have seen a cat which always
carried its tail flat on its back when pleased. The ears vary in shape, and
certain strains, in England, inherit a pencil-like tuft of hairs, above a
quarter of an inch in length, on the tips of their ears; and this same
peculiarity, according to Mr. Blyth, characterises some cats in India. The
great variability in the length of the tail and the lynx-like tufts of
hairs on the ears are apparently analogous to differences in certain wild
species of the genus. A much more important difference, according to
Daubenton,[99] is that the intestines of domestic cats are wider, and a
third longer, than in wild cats of the same size; and this apparently has
been caused by their less strictly carnivorous diet.
* * * * *
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