They are often found hibernating in clusters under house-roofs; but solitary individuals are also found in hollow trees and similar situations. Should the thermometer register 46° F. or more at any time during the winter, the Long-eared Bat awakes and makes a foraging flight—calling attention to his presence by his acute, shrill cry.
The dental formula is: i 2/3, c 1/1, p 2/3, m 3/3 = 36.
Barbastelle (Barbastella barbastellus, Schreber).
One feels inclined to apologise for the poverty of language displayed in the heading above; though no one accepts responsibility for it—the fault lies with the Law of Priority. A strong point in the Linnean System of nomenclature was its binomial character—there were two words only in the name of every animal and plant, the first of the two indicating the genus in which it was grouped, and the second peculiar to the species. In recent years the extension of our knowledge of the world's fauna has led to the breaking up of many of the older genera and a regrouping of the species. In some cases the species name has been adopted to denote a new genus, and then the Law of Priority steps in and says the oldest species name must be retained, so that instead of a binomial we get a mere duplication. When this happens—as above—to be essentially the same as the only "popular" name the species has ever had the result is ludicrous.
Daubenton, who first described it (1759), called it the Bearded Bat (La Barbastelle) owing to tufts of black bristles on the glandular swellings on the muzzle. It is of slender form with long legs and small feet. The irregularly four-sided ears are relatively large, as broad as long, and united by their bases just behind the muzzle. The outer border has a deep notch; the lance-shaped tragus is half the length of the ear. The nostrils open in a naked depression.
The long, soft fur is a very dark brown, but many of the hairs on the upper surface have pale tips which produce a frosted appearance; on the lower surface such light tips are more numerous, and are specially evident along the middle line of the abdomen. The wing, ear, nose, and foot are dusky, appearing lighter than the furred regions.
The head and body measure about two inches, and the tail an inch and three-quarters. The expanse of wings is about ten and a third inches. This and the Long-eared Bat are the only British species whose ears connect; and the form of the ear in each is so distinct that there is no danger of confusing them. It is both solitary and silent in flight, which begins early in the evening, often in daylight; it holds its feet far apart and the tail decurved. In fine weather it flies high. During its diurnal rest it has been found in various retreats, often in company: under thatch of a shed, between the rafters and tiles of outhouses, behind a cottage shutter, in the crevices of walls and trees. Its voice is a metallic squeak or a buzz.
It has one premolar less on each side than the Long-eared Bat, so that its dental formula stands thus: i 2/3, c 1/1, p 2/2, m 3/3 = 34.
As a British Bat, the Barbastelle is found chiefly in the South of England, though it has been recorded from all the English counties between the Severn and the Wash; also Lincoln, Cheshire, and Cumberland (Carlisle). It appears to be absent from Scotland, Ireland, and the Isle of Man.