may be described roughly as a smaller edition of the Common Shrew,
and until recent years was considered to be only the juvenile form of
that species, for which, no doubt, it is still mistaken frequently. It
appears to be widely distributed in Britain, but is local, the areas in
which it occurs being limited and patchy when marked on the map. These
are mostly in wooded districts, but extend from sea-level to the tops of
our highest mountains, for it has been found on Ben Nevis at a height of
4,400 feet. In Ireland, from which the Common Shrew is entirely absent,
its place is taken by the Lesser Shrew, though it is not nearly so
abundant as the Common Shrew is in Britain.
Seen side by side these two species are sufficiently distinct, but apart
they may be taken as identical. The earlier British naturalists had not
learned to discriminate one from the other, and even Bell, as late as
1837, does not mention the Lesser Shrew, though in the second edition
of his work (1874) it appears in a description by Alston. If we take
average length of head and body in an adult Common Shrew as three
inches, we shall find that a similar individual of the Lesser Shrew
measures only two inches and a quarter--a reduction of 25 per cent.
The hind foot without the claws in the Common Shrew is half an inch,
but in the Lesser Shrew it is one-sixth less. The actual length of the
tail is about the same in both species, but proportionately there is a
difference, for whilst that of the Common Shrew only equals half the
length of head and body, in the Lesser Shrew it is equal to two-thirds.
But it has been held that the length of the hind feet alone is
distinctive, and that "any Shrew in which these reach or exceed 12
millimetres may be set down as of the larger species."
The colour of the fur is the brown and white of the common species with
a fairly sharp line of demarcation between them. Though the animal as
a whole is more delicately built, the snout is relatively longer and
thicker; the tail also thicker and more hairy; the forearm and hand are
shorter. The sensitive snout appears to be more useful than its eyes in
hunting. As the result of his experiments, Adams is of opinion that the
sight of Shrews is not much--if at all--better than that of the Mole.
Yet it must hunt incessantly for, owing to its rapid digestion, frequent
meals are a necessity. It is so delicately organised that it has been
found that detention in a trap for only a few minutes is fatal to it;
and captured specimens that have been carried in the hand for a few
hundred yards have died shortly after.
It is an excellent climber, and sometimes enters the upper windows of
houses. It is more nocturnal in its habits than the Common Shrew; but
is subject to the same autumnal mortality. It does not appear to
construct burrows, but utilises those of Mice. Its nests have been
found in various situations, such as a clump of rushes, a hollow tree
stump or a hollow in the ground roofed by a stone; and they have been
of different materials according with the local conditions, moss, dry
grass, fine rush shreds and wood chips variously combined and interwoven
to form a hollow ball.
There are probably two litters of from two to eight young, born between
May and September.
*Water Shrew* (_Neomys fodiens_, Schreber).
The Water Shrew is our largest species, the length of head and body
combined varying from three to three and three-quarter inches, the body
of bulkier build than that of the Common Shrew, and the tail longer than
the body. Its upper parts are dark coloured--from slaty black to dark
brown--and the light ashy grey or dirty white of the under parts appear
pure white by contrast. The snout is shorter and broader than that of
the Common Shrew; the small eyes are blue, and the ears, which are
entirely concealed, bear a tuft of white hairs. The brown feet are
broader and the digits are bordered with stiff hairs which make them
more efficient as paddles; and the tapering flattened tail of the adult
has a double fringe of strong silver-grey hairs along its underside,
constituting a "keel" and making it more efficient as a rudder. The hind
foot usually exceeds three-quarters of an inch. The fur is finer and
thicker than in the other British Shrews; and the upper and lower colour
areas are sharply separated one from the other. Its aquatic habits have
in some districts caused it to be known as Otter-Shrew. The tail is
brown above and lighter below. Variation to full black is frequent, and
albinos have been recorded.
The teeth have coloured tips like those of the other Shrews, but the
points of the incisors are more hooked than in the two species of
_Sorex_; moreover, there are two teeth less, the dental formula standing
thus:--_i 3/1, c 1/1, p 2/1, m 3/3 = 30_. It is these differences
in the teeth that has led to the Water Shrew being placed in a separate
genus.
[Illustration: *Skeleton of Water Shrew.*]
In wandering quietly along the streamside we may perchance see the Water
Shrew sunning itself on a mossy stone by the margin of the water, for
it is active by day as well as by night. We may see it make a sudden
plunge into the stream, and present a beautiful appearance under water,
for the fur carries a good deal of air entangled in it which gives the
submerged body a silvery appearance. It chases the whirligig beetles and
water-gnats on the surface, or routs at the bottom for caddisworms and
other larvæ. Its haunts may often be detected by the little heaps of
caddis cases on the bank, which it has brought ashore and emptied of
their living contents. It eats other aquatic animals, such as snails,
worms, small crustaceans, frogs, and small fishes; is not averse from
a little carrion, and has been caught in a trap that was baited with
cheese. It utters a cricket-like chirp not unlike that of the other
Shrews.
[Illustration: _Pl. 10._ _C 28._
*Water Shrew.*
Neomys fodiens.]
[Illustration: _Pl. 11._ _C 29._
*Common Shrew.*
Female beginning to prepare her nursery nest.]
As he seldom goes more than a couple of yards from the bank, the quiet
observer may take full stock of his proceedings, for the limited range
of his vision does not permit him to see you. He appears to be very
buoyant in the water, swimming with his head slightly above the surface
and the body spread out. Though he may walk for a time along the bottom,
he never gets his fur wet. At times he makes distinct leaps out of the
water, apparently after a flying insect.
His home is a burrow in the bank, and far inside the female lines a
chamber with moss and fine roots, or weaves a round nest of grass and
leaves where in May or June she brings forth her litter of five to eight
minute blind and naked young. These develop rapidly and when they are
five or six weeks old they are independent. There is probably a second
brood in September. Like the other Shrews the males are great fighters.
He is found sometimes at a considerable distance from the water,
apparently seeking a change of diet, or migrating to a more abundant
food supply. It does not hibernate, and may be seen in winter pursuing
its prey beneath the ice. Its chief enemy is the Owl, whose cast-up
pellets frequently contain the skulls of Shrews.
The Water Shrew is much more local in its occurrence than are the other
Shrews. With this reservation it may be said to be widely distributed
throughout England, Wales, and Scotland; and in Staffordshire and
Cheshire has been found at elevations of a thousand feet. It is not
found either in Ireland, the Isle of Man, the Outer Hebrides, the
Orkneys or Shetlands. In the Fen country it is known as the Blind-mouse.
FLYING MAMMALS: BATS
*Bats* (_Chiroptera_).
With the exception of the great class of Birds, the Bats are the only
surviving backboned animals that possess the organs of true flight.
Apart from this specialisation for a life in the air the Bats are very
similar in their organisation to the Insectivora, and long ago Huxley
pointed out that they were exceedingly modified Insectivora; but this
modification marks them off sharply from their nearest allies, and the
authorities have agreed that it constitutes a reason for setting them
apart in a special order--the _Chiroptera_ or wing-handed animals.
So complete has been the adaptation to an aerial life, involving both
pairs of limbs, that they are no longer fitted for progression on the
earth. The fingers of the hand have been so drawn out that they are
longer than the forearm, and the middle finger is at least equal in
length to the head and body, whilst the thumb has been converted into
a hook by means of which the Bat can hang from any rough surface. Over
these exaggerated finger-bones a broad web of skin has been stretched,
and connected not only to the sides of the body but also to the hind
legs as far as the ankle, and then nearly or quite to the tip of the
slender tail. The effect of this great modification, whilst it creates
a pair of great wings, is to render the hind limbs unfitted for ordinary
locomotion, for these are so twisted out of the position assumed in
quadrupeds that the knees are turned backwards. This is the cause of
the awkward, shuffling movements of a Bat on the ground which make it
quickly rise into the air or at least to climb some vertical surface.
Looking at the skeleton of a Bat, we shall find the vertebral column
short, the neck short-boned but broad, the spinal cord being of great
thickness at this part though reduced to a mere thread at the hips. The
ribs are usually flattened and connected to a strong breastbone, which
has a prominent keel for the attachment of powerful muscles controlling
the wings. The tail controls the web connecting the hind legs, which
acts as a rudder in flight and as a net helping to capture and retain
the larger insects upon which the Bat lives.
[Illustration: _Pl. 12._ _C 30._
*Lesser or Pigmy Shrew.*
Sorex minutus.]
[Illustration: _Pl. 13._ _C 31._
*Great Bat or Noctule.*
Nyctalus noctula.]
The permanent teeth--which are quite different from the milk-teeth--vary
in the different species, but they always have distinct roots, and in
the British species the upper surface always runs into points or cusps,
suited for cracking the chitinous shells of beetles.
The Bat's brain is considered to be of a low order; yet its senses are
very acute. Spallanzani, in the latter part of the 18th century made
a number of experiments on Bats, depriving them of sight, smell, and
hearing, and observing their behaviour under such conditions. He found
that when released in a room across which he had stretched numerous
threads to block their flight, they in every case avoided these, even
when directly in their course. They appear to be helped in this matter
by the sensitive whiskers around the muzzle, as well as by the delicate
membranes constituting the wings and the outer ears. In the Horse-shoe
Bats there is also a great development of the appendages to the nose,
known as the nose-leaf, which act as delicate organs of special
perception.
[Illustration: *Skeleton of Bat* (_Vespertilio_).]
In most of the genera there is considerable development of the ear as
compared with other mammals. The little lobe that guards the entrance
to the ear in the human subject, and is known as the tragus, is much
elongated in the Bats so that it becomes a conspicuous feature, and
its variation affords one of the characters for identification of the
species. Our two Horse-shoe Bats alone are without any prominent tragus.
It is considered that the Bat's powers of flight are superior even
to those of the birds. This is especially evident if we watch the
rapidity with which it can change its speed, suddenly stopping when in
full flight, then making sudden swoops and turning somersaults in a way
that would evoke the admiration of the stunt-loving airman. The females
as a rule have larger wings and heavier bodies than the males.
Perhaps to the majority of people the Bat appears to be a creature
without a voice. It does, however, utter a shrill squeak which is so
highly pitched that many human ears are incapable of perceiving it. On
the other hand, the Bat has similar deficiencies; and it has been proved
that low notes, however loud, make no impression on the Bat, though a
sharp clicking sound or the tearing of paper will alarm him at once.
Our Bats are all nocturnal in their habits, though a few indulge in
occasional flights by day. Most of them have definite hours for flight,
the time depending upon the flight period of the insects they prey upon
particularly. They retire for the day into dark situations, such as
hollow trees, caves, outhouses, or under roofs. In these sleeping places
great numbers often congregate, and several species may be represented.
During bad weather--when, of course, their insect prey also remains
under cover--they do not leave their daytime shelter. When asleep their
body temperature falls considerably. In harmony with this nocturnal
habit we find that our Bats are usually dull coloured--some tint of
brown with the underside lighter than the upper.
All the British species hibernate, and before the beginning of this
period they develop a good deal of fat to carry them through it. On any
day in the winter when there is any considerable rise of temperature
they wake at once and look around for insects that have been aroused
by the same means. The larger kinds usually eat their food as they
fly, but the smaller Bats rest for a few moments for this purpose. The
web between the legs and tail ("interfemoral pouch") is mostly used to
hold their prey whilst it is being eaten. It also serves to receive the
newly born young.
[Illustration: _Pl. 14._ _C 32._
*Greater Horse-shoe Bat* (_Rhinolophus ferrum-equinum_)
asleep in cave.]
[Illustration: _Pl. 15._
*Greater Horse-shoe Bat*.
Head enlarged, to show remarkable nose-leaf.]
[Illustration: _Pl. 16._
*Whiskered Bat.*
Myotis mystacinus.]
[Illustration: _Pl. 17._ _D 33._
*Lesser Horse-shoe Bat.*
Rhinolophus hipposideros.]
The young Bat is born blind, but not quite naked. It at once clings to
its mother's fur by means of its claws, and by its teeth to her nipple.
Nursing mothers appear to form colonies apart from the others. The
growth of the young Bat is rapid and it is soon fully covered with fur.
Before it is a fortnight old it is able to leave its mother temporarily,
but it does not lead an independent life until it is about two months
old. Nothing certain is known about the age to which a Bat attains, but
it appears to be about four years.
Until the present century there was an astonishing lack of knowledge of
the life-histories of our native species; but a small but enthusiastic
band of observers have in recent years done much to make good the
deficiency. In this connection the work of Messrs. Alcock, Coward,
Moffat, Oldham, Tomes and Whitaker calls for acknowledgment. They have
hunted far and wide, exploring the sleeping places and hibernacula,
in woods, caves, roofs and belfries, and have established--among other
facts--that our Bats are more numerous in the south, becoming scarcer as
we go west, and that there are few species represented in the fauna of
Scotland. Most of the species appear to be common in some one or more
localities, even if rare elsewhere; and the physical features of a
district have a striking influence on their local abundance or scarcity,
certain species being more discriminative in this respect than others.
The presence of woods, water, and caves appears to be the most
favourable condition governing their comparative plentifulness or
scarcity.
The Bats were known generically in Anglo-Saxon times as Flittermouse and
Reremouse, and these names may be met with still in certain localities;
but to the general public the Bat is still a Bat without distinction
of species. Although there are twelve distinct kinds that breed in the
British Isles, for each of which the naturalist has had to invent an
English as well as an international name, not one of these has got into
ordinary use; so that it is impossible to get any precise information
from those whose occupation gives them opportunities for observation.
*Larger Horse-shoe Bat* (_Rhinolophus ferrum-equinum_, Schreber).
We have two Horse-shoe Bats, distinguished as Larger and Lesser,
and they are regarded as the lowest organised of our Bats. Their
distinguishing feature as a genus is the absence of the tragus from
the ear, and the presence of a leaf-like outgrowth of naked skin on
the muzzle around the nostrils. The broad forepart of this forms the
horse-shoe, a protruding central portion behind the nostrils is known
as the sella, and behind it an erect tapering portion is the lancet.
There can be little doubt that this extraordinary expansion is no mere
ornament, but a sense organ which enables these Bats to execute their
marvellous flight through narrow passages. They are able even to
distinguish invisible obstacles like glass, and they fly low down
among bushes and herbage where they are far more likely to collide
than in the upper air. In these respects their motions are different
from those of the other Bats.
The Larger Horse-shoe Bat is a large and rather heavily built Bat whose
proportions are only slightly exceeded by the Noctule (page 46), our
largest species. The combined length of head and body is about two and
a half inches, and of the tail an inch and a quarter. The forearm is two
inches or more, and the expansion of the wings covers more than thirteen
inches. The large ears are about half an inch broad, narrowing abruptly
to the sharp recurved tip; when laid forward over the face they reach
slightly beyond the tip of the muzzle. The lower portion of the broad
wing membrane is attached to the ankle and the tail almost to the tip
of the latter. The colour of the fur above is reddish-grey; on the
underside pale grey. Its cry is a sparrow-like chirp.
[Illustration: _Pl. 18._ _D 34._
*Whiskered Bat.*
Asleep on roof timbers.]
[Illustration: _Pl. 19._ _D 35._
*Red-grey Bat.*
Myotis nattereri.]
The mouth has a straight broad opening below the swollen muzzle with
its stiff moustache. The large canine teeth are very conspicuous in
contrast with the small incisors. The dental formula for this and the
next species is: _i 1/2, c 1/1, p 2/3, m 3/3 = 32_.
As already indicated, the flight of this Bat is usually low, and it
alights to consume its prey, which it presses against the wing membrane,
the interfemoral pouch not being large enough for the purpose. Its
food consists chiefly of the larger beetles, such as cockchafers and
dor-beetles, the quick-running ground-beetle _Pterostichus_, moths,
flies, bees, and caddis-flies. It appears to be a thirsty creature,
and may be seen lapping water. It takes its daytime sleep in caves,
dark buildings, lofts and roofs. It may hang singly or crowd into
crevices. Mr. Coward found it in the Cheddar caves hanging in bunches.
Their overhead resorts are revealed by heaps of excrement below. Their
natural resting attitude is hanging by the feet head downwards. They
cannot walk on a flat surface, and before alighting on a vertical one
they turn a somersault in the air to get the proper position. Their
senses are so acute that Mr. Chas. Oldham says: "Even when sunk in
winter sleep they appreciate a man's approach. The eyes are, of course,
then shrouded by the wings, and the sense of danger must be conveyed
to them either by hearing, smell, or, as seems to be most probable,
by the exercise of their extraordinary tactile sense, which enables
them to actually feel the approaching danger."
There is but one young at a birth, which occurs at the end of June or in
July. Its eyes are closed, and the underside is quite naked and the skin
purple. The eyes open about the tenth day.
The Larger Horse-shoe Bat has an extensive distribution. From England
it is found through Central Europe and the Mediterranean region, through
the Himalayas to China and southern Japan. In our own country it is
found chiefly in the South-west of England, South and West Wales, but
does not occur in either Scotland or Ireland. The presence or absence
of caves suitable for a winter retreat appears to have some bearing upon
its distribution.
*Lesser Horse-shoe Bat* (_Rhinolophus hipposideros_, Bechstein).
The Lesser Horse-shoe Bat is much smaller and more delicately built than
the species last described. The nose-leaf has a narrower outline and its
sella is more wedge-shaped; the lancet slender with a wedge-shaped tip.
The expanse of wings is less than ten inches, and the length of the
forearm is only an inch and a half. The colour is much the same as in
the larger species, but somewhat darker above and more yellow below.
Its habits are similar also, but, naturally, it does not hunt such large
beetles, nor does it fly so low. It has a more fluttering flight with
intervals of gliding. Its "tchek-tchek" cry is of lower pitch than in
most Bats, and Oldham compares it to a diminutive of the alarm-note of
the Greater Spotted Woodpecker.
The single young one is born somewhat later than in the last species: it
is born like the other with a thin coat of downy hair on the upper side
only.
Males, apparently, are more numerous than females.
The species appears to be more abundant in localities where there are
caves which provide it with the equable temperature it requires in
hibernation. It is most susceptible to wind, and will frequently
remain inactive in its shelter because there is wind outside. Even
tame individuals exhibit a strong desire to get into the most retired
corners and crevices. The first recorded British example was taken in a
cavity over a baker's oven to which it had obtained access through a
small fissure.
[Illustration: _Pl. 20._ _D 36._
*Red-grey Bat.*
Emerging from retreat in hollow tree.]
[Illustration: _Pl. 21._ _D 37._
*Daubenton's Bat.*
Myotis daubentonii.]
It may be considered a common species in the South of England from Kent
to Cornwall, and more sparingly to Wales. It is unknown in East Anglia,
rare in the Midlands, and its northward range terminates at Ripon. In
Ireland it occurs in the West only, in some parts of which it is the
commonest species. Its wider distribution includes Central Europe,
Mediterranean, to Gilgit; northward in Europe to the Baltic.
*Whiskered Bat* (_Myotis mystacinus_, Kuhl).
The small and usually solitary Whiskered Bat was formerly considered to
be a rare species, but it turns out that the naturalists of last century
frequently confused it with the Common Bat--the Pipistrelle--which,
however, is smaller and has a broader muzzle. The head and body measure
about an inch and a half, and the tail the same length. The wings are
narrow, but long, and have an expanse of nine inches.
The soft, long fur of the upper parts is light yellowish-brown in
colour; lighter, almost dirty white below. It extends but slightly on
the wing membrane, and there is little of it on the long, slender ear,
whose outer margin is deeply notched, and the straight, tapering tragus
half the length of the shell of the ear. The hinder margin of the
brownish black wing membrane is continued to the base of the toes,
and the spur (_calcar_) reaches halfway from the ankle to the long
tail. Owing to the length of the fur on the face the small eyes are
almost hidden and the face appears to be very short. There is a bristly
moustache on the upper lip which has suggested its trivial and
scientific names.
Though reputed to be of solitary disposition--and it usually enjoys its
daytime rest apart from its kin--it has been taken in numbers on several
occasions. It makes its appearance early in the evening, flying low
along hedgerows, plantations, and cliffs, its method of hunting being
not to chase flying insects in the air but to pick off such as have
settled on leaves and twigs. It may also be seen at times flying in
the daytime. It has a fondness for the neighbourhood of woods and water,
where it finds many flies, beetles, and moths in flight. It is quite
silent on the wing.