FURTHER NOTES ON THE QUESTIONS OF PROTECTIVE COLORATION, RECOGNITION
MARKS, AND THE INFLUENCE OF ENVIRONMENT ON LIVING ORGANISMS
Occasional resemblance of African mammals to natural
objects--Hartebeests--Elephants--Giraffes--Coloration of
the Somali giraffe--Giraffes not in need of a protective
coloration--Koodoos and sable antelopes--Acute sense of hearing
in the moose--Possible explanation of large size of ears in
the African tragelaphine antelopes--Coloration of bushbucks,
situtungas, and inyalas--Leopards the only enemies of the
smaller bush-haunting antelopes--Recognition marks--Must
render animals conspicuous to friend and foe alike--Ranges
of allied species of antelopes seldom overlap--Hybridisation
sometimes takes place--Wonderful coloration of the
bontebok--Coloration distinctly conspicuous and therefore
not protective--Recognition marks unnecessary--Coloration
of the blesbok--The blesbok merely a duller coloured
bontebok--Difference in the habitat of the two species--The
coloration of both species may be due to the influence of
their respective environments--The weak point in the theory of
protective coloration when applied to large mammals--Hares and
foxes in the Arctic and sub-Arctic Regions--The efficacy of
colour protection at once destroyed by movement--Buffaloes and
lions--General conclusions regarding the theory of protective
coloration as applied to large mammals.
Certain observations have been made and theories propounded on the
occasional resemblance of African mammals to natural objects, which
have never seemed to me to have much significance, although they are
often referred to as valuable observations by writers on natural
history.
Thus it has been said that hartebeests, which are red in colour,
derive protection from their enemies owing to their resemblance not
only in colour but also in shape to ant-heaps, and that giraffes gain
an advantage in the struggle for life owing to the fact that their
long necks look like tree-trunks and their heads and horns like broken
branches.
Well, hartebeests are red in colour wherever they are found all over
Africa. Ant-heaps are only red when they are built of red soil. In
parts of the Bechwanaland Protectorate, where the Cape hartebeest used
to be common, the ant-heaps are a glaring white. In East Africa, in
different portions of which territory hartebeests of three species are
very numerous, all of which are bright red in colour, red ant-heaps
are certainly not a conspicuous feature in all parts of the country,
and there were, if my memory serves me, very few ant-heaps of any size
on the plains where I met with either Coke's, Neumann's, or Jackson's
hartebeests.[2] But even in those districts where the ant-heaps
are red in colour, and neither very much larger nor smaller than
hartebeests, they are usually of one even rounded shape, and it would
only be here and there, where two had been thrown up together forming
a double-humped structure, that anything resembling one of these
animals could be seen. Such unusual natural objects must be anything
but common, and cannot, I believe, have had any effect in determining
the bodily shape of hartebeests, though, if the coloration of animals
is influenced by their environment, red soil and red ant-heaps may have
had their influence on the colour of the ancestral form from which all
the various but nearly allied species of hartebeests have been derived.
[2] The plains along the railway line between Simba and Nairobi, the
open country between Lakes Nakuru and Elmenteita, or the neighbourhood
of the road between Landiani and Ravine Station.
I was once hunting in 1885 with a Boer friend (Cornelis van Rooyen)
near the Umfuli river in Mashunaland. We were riding slowly along,
followed by some Kafirs, and driving a donkey carrying corn for the
horses in front of us, when we saw what we took to be some boulders
of black rock in the open forest ahead, but some distance away, as we
were crossing an open valley at the time. In this particular part of
the country great boulders of black rock were a common feature in the
landscape. Suddenly our donkey pricked his ears, and stretching out his
nose, commenced to bray loudly. Immediately one of the black rocks,
as we had thought them to be, moved, and we soon saw that what we had
taken for rocks were elephants. Our donkey had smelt them before either
my friend or myself or any of our Kafirs had been able to distinguish
what they were. As, however, elephants are only occasionally
encountered in forests through which great boulders of black rock
are scattered, I do not believe that these huge quadrupeds have been
moulded to the shape of rocks by the need of a protective resemblance
to inanimate objects, any more than I think that the abnormal shape of
certain ant-heaps has had anything to do with the production of the
high wither and drooping hind-quarters of the hartebeest.
As to the theory that the long neck and the peculiarly formed head
of the giraffe have been evolved in order to protect this remarkable
animal against its carnivorous foes, by giving it the appearance of
a dead or decayed tree, I personally consider such an idea to be so
fantastic and extravagant as to be unworthy of serious consideration.
In the course of my own hunting experience, I have shot a great many
giraffes to obtain a supply of food for my native followers, and under
the guidance of Bushmen have followed on the tracks of many herds of
these animals until I at length sighted them. In certain parts of the
country frequented by giraffes in Southern Africa, large camel-thorn
trees (_Acacia giraffae_) grow either singly or a few together amongst
a wide expanse of wait-a-bit thorn scrub, which is from 6 to 12 feet
high. From time to time these large trees die and decay, until nothing
is left but a tall straight stem, standing up like a telegraph pole
(only a good deal thicker) amongst the surrounding scrub. When, whilst
following on giraffe spoor through such country, something suddenly
comes in view protruding from the bush, perhaps a mile ahead, the
Bushmen will stop and take a good look at it. Of course at a very great
distance it is impossible for even a Bushman to distinguish between the
tall straight stem of a dead tree standing up out of low bush and the
neck of a solitary old bull giraffe. But if the latter, it is sure soon
to move, unless it is standing watching its human enemies approaching,
in which case it will not be very far away, and I have never known a
Bushman to mistake a giraffe for a tree at any reasonable distance.
As regards the coloration of the species of giraffe inhabiting
South and South-Western Africa, it assimilates very well with its
surroundings, when amongst trees and bush; but as giraffes spend a
great deal of their time passing through open stretches of country
on their way from one feeding-ground to another, they are often very
conspicuous animals.
With respect to the Somali giraffe (_Giraffa reticulata_), a photograph
taken by the photographer who accompanied one of Lord Delamere's
expeditions, showing some of these animals feeding amongst mimosa
trees, gives the impression of a most marvellous harmonisation of
colour and arrangement of marking with their surroundings. But I
cannot help thinking that the facts of the case have been very much
exaggerated in this photograph, which has eliminated all colours from
the picture except black and white. In life, the foliage of the mimosa
is very thin, and I think it probable that the rich dark chestnut
blotches divided by white lines of the Somali giraffe would show
through it at least as distinctly as would the colours of the southern
giraffe in a like position. The Somali giraffe cannot constantly live
amongst mimosa trees, as these only grow in valleys near streams or
dried-up watercourses, and only cover a small proportion of any country
I have yet seen either in South or East Africa.
I must say that I rather distrust the camera as a true interpreter of
nature, as I have seen so many photographs of the nests of small birds
in bushes in which it was very difficult even for a trained eye to
find the nest at all, although in all probability it would have been
comparatively easy to detect these nests in the actual bushes in which
they were placed.
Speaking of the Somali giraffe, Colonel J. J. Harrison, in a footnote
to a photograph of one of these animals shot by himself right out
in open country, which appeared in the _Bystander_ for January 30,
1907, says: "These handsome coloured giraffes are very striking when
seen standing in the sun. Of a rich bright chestnut colour, with pure
white rings, they stand out splendidly as compared with the dull grey
colouring of the more southern giraffe."
However, it appears to me that to whatever extent the coloration of
the various races of giraffes harmonises with their surroundings,
that result must have been brought about by the influence of their
environment rather than by the need of protective coloration, for
I cannot believe that the struggle for life against the attacks
of carnivorous animals can have been sufficiently severe to have
influenced the colour and the arrangement of markings in giraffes.
That lions occasionally attack and kill giraffes is an undoubted fact,
and, as I shall relate in a subsequent chapter, I have also known a
case of a very young giraffe having been attacked by two leopards; but
in South Africa giraffes are found in the greatest numbers in those
parts of the country where, except during the rainy season, there is
very little surface water, and where other species of game are far from
plentiful. Into such districts lions do not often penetrate, and when
giraffes are found in country where there is plenty of water, zebras,
buffaloes, and antelopes of various kinds will also be numerous, and
these animals will certainly be preyed upon in preference. At any rate,
my own experience would lead me to believe that although lions can and
do kill giraffes upon occasion, they do not habitually prey upon these
animals. Moreover, when giraffes are killed by lions, they are in all
probability followed by scent and killed in the dark.
Altogether, the theory that the colour of the giraffe has been evolved
by the necessity for concealment and protection from the attacks of
carnivorous animals does not seem to me to be at all well supported by
the life-history of that animal as seen by a practical hunter; but the
fact that the coloration of this remarkable animal assimilates very
well with the dull and monotonous shades of the trees and bushes in
the parched and waterless districts it usually frequents, is a strong
argument in favour of there being a law which, working through the
ages, tends to bring the colours of all organic beings into harmony
with their surroundings, irrespective of any special benefit they
may receive in the way of protection from enemies by such harmonious
coloration.
Turning to the striped and spotted forest antelopes inhabiting
various parts of Africa, I think there is some misconception amongst
naturalists who have not visited that country as to the general
surroundings amongst which the various species live. The magnificent
koodoo, with his long spiral horns, striped body, spotted cheeks, nose
marked with a white arrow, and throat adorned with a long fringe of
hair, is often spoken of as an inhabitant of dense jungle. This is,
however, by no means the case, for although koodoos are never found on
open plains, they are, on the other hand, seldom met with in really
dense jungle.
The range of the koodoo to the south of the Zambesi extends farther to
the south and west than that of the sable antelope, but I think I am
justified in saying that up to the time of the deplorable visitation
of rinderpest in 1896, wherever, between the Limpopo and the Zambesi,
sable antelopes were to be met with, there koodoos were also to
be found, and outside of districts infested by the "tse-tse" fly,
excepting amongst rocky hills, I have never met with the latter animals
in any country where I was not able to gallop after them on horseback.
Living as they do in surroundings so very similar to those frequented
by sable antelopes, I have never been able to understand why koodoos
should have such much larger ears than the former animals. I have never
been struck with the acute sense of hearing in koodoos as I have been
in the case of the moose of North America, and I should scarcely think
that this sense would often save them from the noiseless approach of
such animals as lions or leopards, to which they very frequently fall a
prey, judging by the number of the remains of koodoo bulls which I have
found that had been killed by the former animals.
I have often wondered whether the large size of the ears observable in
the African tragelaphine antelopes, which are all forests dwellers
(with the exception of the situtunga, which lives in dense beds of
reeds), may not be useful to them by enabling the males and females
to hear one another's calls during the mating season. The large
ears and exquisite sense of hearing of the moose, which is also a
forest-dwelling animal, have undoubtedly been developed for the purpose
of enabling the males and females to find one another in the breeding
season, and not for protection against the attacks of wolves. I have
frequently heard both koodoos and bushbucks calling by night and also
in the early morning. The noise they make is a sort of bark or cough.
Antelopes inhabiting open plains are very gregarious, and in the
daytime would always be able to find their mates by sight. I have never
heard them making anything but low grunting noises. As it is often
assumed by naturalists that all bush-haunting species of antelopes have
very large ears, it is perhaps worth noticing that in the little blue
buck and the red bush duiker of South-East Africa, which both live
in dense jungle near the coast, the ears are very small; whilst in
the steinbuck, on the other hand, which is always found in very open
country and never in thick bush, the ears are very large--both long and
broad.
The coloration observable in the different races of bushbucks
inhabiting different localities, as well as in the situtunga and inyala
antelopes, is, I think, very interesting and suggestive. It may, I
think, be taken for granted that all the races of African bushbucks
have been derived from an ancestral form which was both striped and
spotted; but in the bushbucks found near the coast of the Cape Colony
and Natal, the adult males are deep dark brown in colour, often
absolutely devoid of any white spots or stripes on face or body, whilst
the adult females are yellowish red, with only a few white spots on
the flanks. Now these most southerly of the African bushbucks live
in really dense bush, and often in deep ravines, where the sun never
penetrates. Their habitat too being near the sea-coast, the climate
must be damper than in the interior of the continent. In the northern
parts of Mashunaland and along the Central Zambesi and Chobi rivers
the bushbucks live in forest and bush which is seldom very dense,
and through most of which the sunlight plays constantly. In these
districts the males are, when adult, beautifully striped and spotted,
and the ground colour of their coats is rich red and dark brown, the
females being of a dark rich red and also well striped and spotted.
The situtunga antelopes live (on the Chobi and Central Zambesi) in
immense beds of reeds which are always of one dull monotonous greyish
green or brown. The adult animals are, as might be expected by those
who believe in the direct influence of environment, of a uniform light
brown colour, except that the spots on the cheeks and the arrow-shaped
mark across the nose, present in most tragelaphine antelopes, are
still discernible. In the inyala antelope, which inhabits thick jungly
tracts of bush along the south-east coast of Africa, the adult male
is of a deep dark grey in general body colour, with a few scarcely
visible vertical white stripes. The young males and the adult females
are, however, of a brilliant light red colour, profusely striped and
spotted with white. The young of all bushbucks and of the inyala are
reddish in ground colour, striped and spotted with white. The fœtal
young of the situtunga found in the marshes of the Chobi are of the
colour of a dark moleskin beautifully banded and spotted with pale
yellow, and it is, I think, a very remarkable fact that these stripes
and spots are identical in position with those found on the adult Chobi
bushbuck, which is strong evidence, I think, that both these animals
are descended from one ancestral form.
Now the only animal that preys habitually on bushbucks, inyalas, and
situtungas is the leopard, and as leopards hunt by night and by scent,
I cannot believe that the very different outward appearance of the
various races of bushbucks inhabiting different parts of Africa is to
be accounted for by the theory of protective coloration. The males
and females of the Cape bushbuck and of the inyala antelope are very
different one from another in the colour of their coats, but this does
not seem to be prejudicial to either sex, though there is absolutely no
difference in their habits or their habitat. In all the different races
of bushbucks, however, with which I am acquainted, the males are much
darker in colour than the females, so that it is not so very surprising
that in the case of the inyala and the Cape bushbuck the males should
have been the first to lose their stripes and spots in a sombre
environment. In the case of the Cape bushbuck the adult females have
already lost all the stripes and most of the spots of the ancestral
form. The female inyala is, however, one of the most distinctly striped
and spotted representatives of the tragelaphine group.
I cannot see that facts support the opinion that the uniform dull brown
coloration of both sexes of the southern race of situtunga has been
brought about for the purpose of protection from carnivorous enemies.
During the daytime these animals live in the midst of beds of reeds
growing in water where they cannot be approached except by wading; but
at night they are often killed by leopards, and perhaps sometimes by
lions, whilst feeding just outside the reed beds, on open ground which
has perhaps been recently swept by a veld fire, and where young reeds
and grass are just sprouting. At such a time their actual colour can
be of no more use in the way of protecting them from their keen-scented
feline foes than if it were black or red or grey. To me it seems far
more probable that the situtunga has gradually lost the stripes and
spots of the ancestral form from which it is derived, and assumed a
uniform dull brown coloration, because it has lived for ages amongst
reed beds of one dull monotonous colour, than because a uniform brown
coat affords it a special protection against carnivorous foes.
I gather from the writings of Mr. A. R. Wallace and other well-known
naturalists that, whereas the coloration of all animals is supposed to
be due to the need of protection from carnivorous beasts, many species
have developed in addition what are known as recognition marks, to
enable them to distinguish members of their own species from nearly
allied forms, or to help them to quickly recognise and rejoin the
members of the herd or family from which they may have been separated.
That many large mammals belonging to different genera, and living
in widely separated parts of the globe, are marked with conspicuous
patches of white on the rump, neck, or face, or throw up bushy tails
when running, showing a large white under surface, is an indisputable
fact, though it is not possible to say that the possession of such
a conspicuous coloration is absolutely necessary to the well-being
of any particular species, because there will nearly always be other
species living in the same country, and subject to the attacks of the
same predatory animals, in which these so-called recognition marks are
absent. However, on the supposition that carnivorous animals hunt by
sight, it seems to me that no animal can be said to be protectively
coloured which is marked in any way so conspicuously as to be
recognisable by others of its own species at a distance, for it would
be equally recognisable by all predatory animals, and caribou and
white-tailed deer or African antelopes cannot escape from wolves or
wild dogs by running like rabbits into burrows.
Personally, I cannot see why large antelopes which live in herds on
open plains should require special recognition marks, as in such
localities the bulk of an animal's whole body would be plainly
visible at a great distance no matter what its colour might be. If an
antelope became separated from its fellows by night, all so-called
recognition marks would be invisible at a very short distance. It must
be remembered, however, that every species of animal has a peculiar and
very distinctive smell of its own, and my own observations would lead
me to believe that most wild animals recognise one another, as a rule,
more by scent than by sight.
It seems difficult to believe that there can be any truth in the theory
suggested by Mr. Wallace, that recognition marks have been developed in
certain species of large mammals because they are necessary to enable
nearly allied species of animals to know their own kind at a glance,
and so prevent interbreeding; for the ranges of very nearly allied
forms of one genus, such as the various species of hartebeests and
oryxes, or the bontebok and the blesbok, very seldom overlap, and so
each species keeps true of necessity and without the help of special
recognition marks. Where the ranges of two nearly allied species do
overlap interbreeding probably will take place.
There seems little doubt that the species of hartebeest known as
Neumann's hartebeest has interbred with Jackson's hartebeest in
certain districts where the ranges of the two species meet. In the
neighbourhood of Lake Nakuru, in British East Africa, I shot, in
February 1903, a hartebeest which was not a Jackson's hartebeest, but
which closely resembled an animal of that species in the character of
its horns and the measurements of its skull, whilst all the others in
the same herd appeared to be true Neumann's. I have known too of one
undoubted case of the interbreeding of the South African hartebeest
(_B. Caama_) with the tsessebe (_Damaliseus lunatus_).
This animal (an adult male) was shot by my friend Cornelis van
Rooyen in Western Matabeleland, where the ranges of the two species
just overlap. In coloration it was like a tsessebe, but had the
comparatively bushy tail of the hartebeest, whilst its skull and horns
(which are, I am glad to say, in the collection of the Natural History
Museum at South Kensington) are exactly intermediate between those
of the two parent species. This skull has been very unsatisfactorily
labelled "supposed hybrid between _B. Caama_ and _D. lunatus_." But as,
when I presented it to the Natural History Museum, I gave at the same
time a full description of the animal to which it had belonged, which I
got from the man who actually shot it, there is no supposition in the
matter. If the skull and horns in question are not those of a hybrid
between the South African hartebeest and the tsessebe, then they must
belong to an animal still unknown to science.
There is, I think, no large mammal in the whole world whose coat shows
a greater richness of bloom and a more abrupt contrast of colours than
the bontebok, so called by the old Dutch colonists of the Cape because
of its many coloured hide, for _bont_ means spotted, or blotched, or
variegated. The whole neck, the chest, the sides and under parts of
the head, and the sides of the body of this remarkable antelope are of
a rich dark brown, and the central part of the back is of a beautiful
purple lilac; whilst, in strong contrast to these rich dark colours,
the whole front of the face, a good-sized patch on the rump, the whole
belly, and the legs are of a pure and brilliant white. In life, and
when they are in good condition, a wonderful sheen plays and shimmers
over the glossy coats of these beautifully coloured animals, which
fully atones for the want of grace and refinement in the shape of their
heads and the heavy build of their bodies.
Now, a practical acquaintance with the very limited extent of country
in which the bontebok has been evolved, and where the survivors of the
race still live, makes it quite impossible for me to believe that the
extraordinarily brilliant colouring of this species of antelope can
have been gradually developed in order to make it inconspicuous and
therefore difficult of detection by carnivorous animals, nor can I
believe that it has been evolved for the purpose of mutual recognition
between individuals of the species; for although the snow-white blaze
down the face or the white rump patch might very well subserve such a
purpose, I see no necessity, looking to the habitat and the habits of
the bontebok, for special recognition marks.
Now, before proceeding further, I think I ought to say a word as to the
points of resemblance and the differences between the bontebok and its
near ally the blesbok.
In the latter, the wonderful contrasts of colour to be seen in the
former are considerably toned down; but the difference between the
two species is merely superficial. The general body colour of the
blesbok is dark brown, but not so dark as on the neck and sides of
the bontebok, and the delicate purply lilac colour of the back in the
latter species is altogether wanting in the former. In the blesbok,
too, the colour of the rump just above the tail, which in the bontebok
is snow-white, is brown, though of a paler shade than any other
part of the body. In the blesbok, too, the white face "blaze" is
not continuous from the horns downwards as in the bontebok, but is
interrupted above the eyes by a bar of brown. The legs, too, in the
blesbok are not so white as in the bontebok, and whilst the horns of
the latter species are always perfectly black, in the former they are
of a greenish colour.
In a word, the differences between the bontebok and the blesbok are
confined to the intensity of the colours on various portions of their
hides, the former being much more brilliantly coloured than the latter.
Owing to the fact that the early Dutch settlers at the Cape first met
with the antelopes which they called bonteboks on the plains near
Cape Agulhas, and subsequently at first gave the same name to the
nearly allied species which was discovered about one hundred years
later in the neighbourhood of the Orange river, although these latter
were undoubtedly blesboks and not bonteboks, a great confusion arose
between these two nearly allied species, which I think that I was the
first to clear up, in the article on the bontebok which I contributed
to the _Great and Small Game of Africa_, published by Rowland Ward,
Limited, in 1899. I cannot go into all the arguments I then used, but
there can be no doubt that the animals which Captain (afterwards Sir
Cornwallis) Harris first met with on the bontebok flats near the Orange
river, in the Colesburg division of the Cape Colony, were blesboks
and not bonteboks, and that all the millions of antelopes of the same
species which he subsequently saw to the north of the Orange river and
thought to be bonteboks were also all blesboks, and that he never saw
a bontebok at all until after his return to the Cape, when he made a
special journey to Cape Agulhas to secure specimens of that species,
as he was "anxious to ascertain whether the animal rigorously protected
in the neighbourhood of Cape Agulhas differed in any respect from that
found in the interior, _as pretended by the colonists_."
I think myself that the correct determination of the true distribution
of these two nearly allied species of antelopes is of the utmost
importance to the question as to the influence of environment on the
coloration of animals.
I imagine that the white-faced bontebok was evolved from the same
ancestral form as the topi and the tiang of East and Northern Africa,
for the new-born bontebok as well as the blesbok has a blackish brown
face, and I believe--however fantastic this belief may appear to
be--that the wonderfully rich and varied coloration of this remarkable
antelope has been brought about purely through the influence of its
exceptional environment. The plains where these animals live lie along
the shore of a deep blue sea, the ground beneath their feet is at
certain seasons of the year carpeted with wild flowers, which grow
in such profusion that they give a distinct colour to the landscape,
whilst above them rises a range of mountains of a considerable
altitude, the upper parts of which are often covered with a mantle of
pure white snow. I cannot imagine how any one who has seen bonteboks
on the plains they inhabit can believe that their white rumps, faces,
bellies, and legs, contrasting as they do so vividly with the dark
rich brown of their sides and necks, can afford them any protection
against their carnivorous foes; nor, although a white rump or face is
a conspicuous mark, can I see the necessity of recognition marks for
animals which live on open plains where the vegetation is short, and
where an animal's whole body can be seen at a long distance.
In the blesbok, which also lives on open plains, the white rump patch
so conspicuous in the bontebok has become pale brown, as, I think,
through the influence of the dull monotonous colours of the dreary,
dull-coloured country in which it lives. Ages ago no doubt the bontebok
spread northwards through the karroo into the countries beyond the
Orange and the Vaal rivers, but the gradual desiccation of the whole
of South-Western Africa, which has been going on for a very long
time, must have gradually driven all the bonteboks outside the Cape
peninsula northwards to the Orange river, and completely separated
them from their relatives still living near Cape Agulhas. These latter
have retained all their richness of coloration brought about by the
influence of their very striking surroundings, the deep blue of the
sea, the snow on the mountains, and the bloom of innumerable wild
flowers. The northern herds moved into open plains, in themselves very
similar to the plains near Cape Agulhas, but they are never carpeted
with wild flowers, nor are they skirted by a deep blue sea, nor ever
overlooked by snow-covered mountains. Is it not possible that the
differences which exist to-day between the coloration of the bontebok
and the blesbok are entirely the result of the absence of any kind of
colour but various monotonous shades of brown in the countries in which
the latter species has now been living for a long period of time?
Not only has the rich and beautifully variegated body colouring of the
bontebok become an almost uniform dark brown in the blesbok, but the
snow-white disc on the rump of the former animal has turned to a pale
brown in the latter, whilst the area of white on the face and legs of
the bontebok has already been considerably contracted in the blesbok.
Personally, I look upon the blesbok as a faded bontebok; faded because
it moved northwards out of the richly coloured environment in which it
was first evolved into the dull-coloured plains of its present habitat,
where it subsequently became isolated owing to the desiccation of the
intervening country.
Could the opening up of Africa by the destructive civilised races have
been delayed for a few hundred or a few thousand years, the blesbok
would no doubt have lost the white blaze down the face as completely
as it has lost the white disc over the tail, which is so conspicuous
a feature in the coloration of its immediate ancestor, the bontebok.
To those who believe that every spot or stripe or patch of colour on
every animal is a beautiful illustration of the truth of the theory
of protective coloration, this may seem a very fanciful idea. Yet I
feel convinced that the influence of environment has played a greater
part than is generally believed in the evolution of colour in living
organisms. The weak point in the theory of protective coloration when
applied to large mammals is the fact that all carnivorous animals are
nocturnal and seek their prey habitually by night and by scent, and
only occasionally by daylight and by sight.
I submit that the beautiful case in the Central Hall of the Natural
History Museum at South Kensington--showing an Arctic fox, in its
white winter coat, approaching a Polar hare, also in winter dress, and
an ermine (stoat) hunting for ptarmigan (evidently by sight)--gives
an entirely false view of the struggle for life as carried on by
animals inhabiting the Arctic Regions, for it conveys the idea of the
carnivorous animals of those snow-covered wastes hunting for their prey
in a bright light and by eyesight alone.
But the truth is that the Arctic winter, during the long continuance of
which all living resident creatures, with the exception of the musk ox,
become white,[3] is one long night, in the gloom of which the wolves
and the foxes and the ermines (stoats) search for and find their prey
by scent alone, just as foxes, stoats, and weasels do in this country.
As long as a hare gives out any scent at all, a fox will be able to
follow and find it. The fact that the hare has turned white in the
snow-covered ground in which it is living will not help it as long as
it throws out the scent of its species, nor can it be shown that the
foxes of the sub-Arctic regions, which never turn white in winter, have
any greater difficulty in approaching and killing the white hares on
which they live than the white Arctic foxes experience in catching the
Polar hares.
[3] I do not admit that the raven is a truly Arctic bird. Nansen, in
_Farthest North_, although he kept careful records of all the birds
seen during the three years his expedition lasted, never mentions
having seen a raven, which I believe has only penetrated into the
Arctic Regions, as an excursionist, in comparatively recent times,
following the whaling ships, and living on the carcases of the whales
and seals killed.
There is one other point regarding the protection afforded by colour
to large mammals against carnivorous foes which I think has not been
sufficiently considered by naturalists, and that is, that no matter how
well the colour of an animal may harmonise with its surroundings as
long as it remains perfectly still, as soon as it moves "it jumps to
the eyes," as the French say, no matter what its colour may be. What
is called protective coloration to be effective must be motionless.
Movement, even very slight movement, at once destroys its efficacy. But
no herbivorous animals can remain constantly motionless. They lie down
and rest certainly during the heat of the day, which is, however, just
the time when all carnivorous animals are sleeping. At night and in the
early mornings and late evenings they move about feeding, and it is at
such times that carnivorous animals hunt for their prey. In the dark
these latter are undoubtedly guided by scent and not by sight, and I
cannot see that it matters much to them whether the beasts on which
they prey are black or red or grey or spotted or striped; whilst, if
they should happen to be still hunting after daylight, any antelopes
or other animals feeding and moving about within their range of vision
would at once be seen whatever their colour might be. Every old hunter
knows how easy it is to overlook any animal, no matter what its colour
or surroundings, as long as it is motionless, and how easy it is to see
it as soon as ever it moves.
I have never yet heard any explanation given of the black, and
therefore most conspicuous, coloration of the Cape buffalo. If any
animals needed protective coloration buffaloes certainly did, for in
the interior of South Africa they formed the favourite food of the
lion, and enormous numbers of them must have been annually killed by
these powerful carnivora, which seemed to live with and follow the
larger herds in all their wanderings.
It certainly seems very strange to me that giraffes, which are very
seldom killed by lions or other carnivora, should have found it
necessary to evolve a colour which harmonises with their surroundings,
as a protection against such foes, whilst buffaloes, which in many
districts used once to form the principal food for the lions living
in the same countries, have retained throughout the ages a coloration
which is everywhere except in deep shade singularly conspicuous.
Altogether, a very long experience of the larger mammals inhabiting
Africa and some other parts of the world has convinced me that neither
the need of protection against carnivorous foes nor the theory of
recognition marks can satisfactorily explain all the wonderful
diversity of colour to be seen in the coats of wild animals.