BATS. 
250 
adjacent parts of the face, forming what is generally known as the “ nose-leaf.” 
These folds of skin may be either comparatively small and simple, or so large as to 
form a kind of mask, communicating a most extraordinary physiognomy to the 
hats in which they occur. The various membranes forming these nose-leaves are 
always fringed with long and line hairs, which evidently correspond to the 
“ whiskers ” of the cat; and we may accordingly regard these nose-leaves merely 
as an excessive development of the cat’s whiskers, accompanied by leaf - like 
growths from the skin of the nose. It has been observed by Dr. Dobson—our 
great authority on bats—that those species which are without nose-leaves are in 
the habit of flying at dawn or twilight, while the leaf-nosed kinds are more 
strictly nocturnal, and are thus much less frequently shot when on the wing. 
The fruit-eating bats, whose habits are very different from the other members of 
the order, never have these nose-leaves, and their ears are small and unprovided 
with a tragus; there being no necessity for the extreme delicacy of tactile 
perception required in the other groups. 
When on the wing, the ordinary insectivorous bats utter a short, 
sharp squeak of such an extremely high pitch that to many persons 
it is quite inaudible, although to others, whose ears are attuned to the reception of 
such high-pitched tones, these cries are of piercing intensity. 
The insect-eating species of bats inhabiting’ the temperate regions, 
Migrations *— 5 o i o * 
being dependent for their nourishment upon a full supply of insects, 
must in winter either migrate to warmer regions, or hibernate. In our own 
country all the species hibernate, and do not appear to migrate at all; and it is 
probable that this hibernating habit also holds good for the whole of the European 
bats. It seems, however, that at least one North American species—the Vespertilio 
borealis —migrates to a certain extent during the summer, not visiting the more 
northerly portions of its habitat till August, when the long intense twilights, 
which would be unsuitable to its habits, have ceased. In Canada, moreover, Dr. 
Hart Merriam is of opinion that at least two species of bats regularly perform 
extensive migrations in order to avoid the intense cold of the northern winter. 
This eloquent writer observes that “ all North American bats, except when their 
habits have been modified by proximity to man, may be classed as cave-dwelling or 
tree-dwelling, according to the places in which they spend the day. As a rule, the 
cave-dwelling species live in large colonies, while the tree-dwelling live singly or in 
small companies. Now, it is well known that the temperature in caves, even in 
high latitudes, is little affected by the external atmosphere, but remains nearly 
uniform throughout the year; while in holes in trees the temperature is about the 
same as that of the surrounding air. Hence, animals inhabiting caves can pass the 
winter much farther north than species living in hollow trees. The hoary bat 
(Atalapha cinerea) is a tree-dwelling species, and its home is in the Canadian 
fauna, from the Adirondack Mountains northward. Therefore, on purely theoretical 
grounds, it should be expected to migrate.” Now, specimens of this bat have been 
not unfrequently observed in the autumn and winter from localities so far to the 
southward of its usual habitat, that there would seem to be no longer any reasonable 
doubt as to its being truly migratory. It has, indeed, been found so far away from 
its ordinary summer haunts as the Bermudas, where Mr. J. M. Jones states that it 
