ORANGE BAT.
Another Australian species of Leaf-nosed Bat, belonging, however, to a distinct genus, of which, indeed, it is the sole representative, is the Orange Bat (Rhinonycteris aurantia, see [p. 285]). This species, which is about two inches long, is clothed with a soft fur, which, in the male, is of a bright orange colour, and in the female pale yellow. This coloration is exceedingly remarkable in an animal of nocturnal habits, as these are generally rather sombre in their tints. The nose-leaf in the Orange Bat is somewhat similar in its character to that of the true Rhinolophi, but in its other peculiarities this Bat is rather related to those which we shall next have to describe, and thus forms a sort of transition between the two groups. It has the toes equal, and composed of only two phalanges, a character which distinguishes it from the preceding species; whilst its resemblance to them in the structure of the nose-leaf serves to separate it from its following allies. The teeth resemble those of Rhinolophus. In repose the tail and interfemoral membrane are generally turned back, which appears to be the case in some at all events of the following species. This species inhabits Northern Australia, and is especially abundant on the Coburg peninsula. It reposes during the day in hollow spouts and holes of the gum-trees.
THE DIADEM BAT.[173]
HEAD OF THE MALE AND FEMALE DIADEM BAT, ENLARGED.
(After Dobson.)
Whilst the Rhinolophi are chiefly inhabitants of elevated localities, especially in tropical regions, the members of the second large genus of Horseshoe Bats (Phyllorhina) for the most part frequent the plains and lower hills of the same countries. The most definite character separating the Phyllorhinæ from the Rhinolophi is the presence of only two phalanges (joints) in all the toes of the hind feet, the first toe in Rhinolophus having three such joints. The nose-leaf consists of a horseshoe and of two other portions, which, however, differ considerably in form from those of Rhinolophus; the anterior portion being horseshoe-shaped, but not notched in front, the intermediate part not forming a prominent process, but broad and heart-shaped, and the posterior part broad, erect, and concave in front. The number of teeth is the same as in Rhinolophus, except in one species (P. tridens), which has only a single pre-molar on each side in the upper jaw. Fourteen species of this genus are cited by Mr. Dobson as inhabiting the East Indies and the islands of the Eastern Archipelago, and one of them, the Diadem Bat (Phyllorhina armigera), which is found among the mountains of Northern India, extends its range as far north as Amoy in China. The characters of the nose-leaf in this species will be seen from the [annexed figures], which show strikingly the great complexity of this curious apparatus. Behind the nose-leaf is the aperture of a peculiar sac situated in the forehead, which is characteristic of many species of the genus, and which can be turned out like the finger of a glove at the pleasure of the animal, and the surface of which secretes a waxy substance. Its centre bears a tuft of straight hairs, the tips of which project from the orifice when the sac is drawn in. The Diadem Bat is rather a large species, the head and body measuring from three and a half to four inches in length, and the expanse of the wings being about two feet. Its general colour is light brown, darker on the upper surface, where the hairs are ringed with three colours—pale sepia at the base, then grey, then dark sepia, with the extreme tips a little paler.
The late Captain Hutton has given an account of the habits of this species as observed by him at Mussooree, where specimens were captured at elevations of 5,500 and 6,000 feet above the sea-level. At the latter elevation a pair resided in a loft, from which they issued every evening about dusk, and flew with a slow, deliberate flight round the house, from which they never departed to any great distance. They did not remain on the wing long at a time, but retired at intervals to their dwelling-place in the loft. The same writer describes these Bats, which seem to emerge from their concealment very early in the evening, as leisurely wheeling with noiseless flight round some wide-spreading oak, attracted by the loud discordant note of a large Cicada, which is abundant during the rainy season, and only pours forth its clamorous evening song just as the sun begins to dip below the horizon. “It is during this dreadfully harsh concert,” he adds, “when almost every tree sends forth its stunning notes, that this Bat emerges from its hiding-place, wheeling round and round the trees, scanning each branch as he slowly passes by, now rising to a higher circle, and then descending towards the lower branches, until at length, detecting the unfortunate minstrel, it darts suddenly into the tree, and snatching the still screaming insect from its perch, bears it away.”
In captivity, according to Captain Hutton, the large ears of this animal are kept in a constant, rapid, tremulous motion, and the creature emits a low purring sound, which is exchanged for a sharp squeak when it is alarmed or irritated. When it is suspended in a resting attitude the tail and interfemoral membrane are turned up, not in front, as usual in Bats, but behind, upon the lower part of the back. In this species and its allies Captain Hutton further noticed that when they are disturbed “the whole of the facial crests are kept in a state of constant agitation; and as the animal hangs suspended by the feet, the head and muzzle are stretched forth, and turned about in every direction, as if for the purpose of sniffing out the presence of danger, and ascertaining the cause of the disturbance.”[174]