HABITS. 
25 1 
Distribution. 
is observed occasionally at dnsk during the autumn months hawking about 
according to its nature in search of insects; but as it is never seen except at that 
particular season, it is clear that it is not a resident, but merely blown across the 
ocean by those violent north-west gales which also usually bring numbers of birds 
from the American continent. The hoary bat is, however, not the only species in 
which there is evidence of periodical migrations. Thus Dr. Merriam tells us that 
the silver-haired bat (Vesperugo noctivagans), which ranges as far north as 
Hudson’s Bay, is known to visit every spring and autumn a solitary lighthouse 
situated on a solitary rock off the coast of Maine, fifteen miles from the nearest 
island and thirty miles from the mainland. This rock being uninhabited per¬ 
manently by bats, the occurrence of these stray individuals at the spring and fall 
seems to afford perfectly conclusive evidence of the migratory habits of the 
particular species to which they belong. 
In regard to their geographical distribution, it may be observed 
that bats are found over almost the whole world; one species at least 
even extending as far northwards as the Arctic circle. They are far more abundant 
within the tropics and the warmer parts of the temperate zones than elsewhere; 
and it is to those regions alone that the larger species are restricted. Indeed, the 
bats, according to Mr. Wallace, may be regarded as some of the most characteristic 
of the Mammals of the tropical zone, occupying in this respect a position second 
only to that held by the apes, monkeys, and lemurs, and becoming suddenly much 
less plentiful, both as regards the number of individuals and of species, when we 
pass into the temperate zone, and still more reduced in both respects when we reach 
the colder parts of those regions. 
In some instances particular family groups of bats are confined more or less 
exclusively to particular regions of the earth’s surface; although others enjoy an 
almost world-wide distribution. For instance, while the fruit-bats are entirely 
confined to the warmer regions of the Old World, and the vampires and their 
allies to America, some of the more common types of ordinary European bats, like 
Vesperugo and Vespertilio, are almost cosmopolitan. It will be found that these 
cosmopolitan forms belong to the more generalised types, while those restricted to 
particular districts are usually the more specialised form. It is somewhat curious 
that, according to Dr. Dobson, bats are quite unknown in Iceland, St. Helena, 
Kerguelen, and the Galapagos Islands. 
The number of species of bats known to science is now enormous. 
In a list published in 1878, Dr. Dobson recognised no less than four 
hundred distinct species, arranged in eighty genera, and six families. Since that 
date the number has, however, been so largely increased, that we shall probably be 
not far wrong in setting it down as but little, if at all, short of four hundred and 
fifty. With such a portentous list to deal with, it will be obvious that, in a work 
like the present, all that can be attempted is to indicate some of the more generally 
interesting and leading types, leaving the others for technical treatises. The old 
English name Flittermouse, by which these animals were known to our ancestors, and 
by which they are still designated in certain parts of the country, conveys a very 
accurate notion of their zoological position, if we use the term mouse in the popular 
signification, in which it embraces animals like the shrews, as well as the true mice. 
Numbers. 
