In this abundant American Bat the fur is generally of a smoky-brown colour, with the bases of the hairs whitish; on the lower surface some of the hairs are entirely white, and the rest brown, with the base and apex whitish. The length of the head and body is from three and a half to four and a half inches, and that of the tail about two inches, nearly half of which projects beyond the membrane. The heel-spurs are very long. In this and the other species of Molossus, the intermaxillary bones are united, and the upper incisors close together in front.[231]
The Smoky Mastiff Bat is a well-known South American species, and extends also into the West Indian islands. In Jamaica it was observed and described by Mr. Gosse under the name of the Monk Bat, in allusion to the fact that he found the species living in large communities, but always of one sex. Mr. Osburn also observed it in the same island, and has given a long account of its habits. In the house in which he was living at Shettlewood, these Bats swarmed in the roof, and during the breeding-season, his bedroom, situated immediately below, was rendered so offensive by their peculiar odour, that he was compelled to have every window left wide open at night. The Bats passed out from the roof under the eaves, but not unfrequently small parties of them would come in through the windows and take a short flight round the room. A man sent up into the roof brought down four or five quarts of the Bats, all of which proved to be males. These Bats also live in holes in dead stumps of cocoa-nut trees, and Mr. Osburn describes as follows the results of felling one of the stumps thus occupied. He says:—“It was broken into fragments by the fall, and among them a perfect hecatomb of these little Bats, scattered into two distinct heaps, corresponding to a high and a lower storey in the tree. There must have been at least 150 or 200 altogether. The heap which occupied the upper hole were exclusively males; those in the lower, females, in large proportion, though there seemed a male here and there among them.” Mr. Osburn’s observations thus strikingly confirm those of Mr. Gosse as to the curious habit of segregation on the part of the males of this species, which induced the latter gentleman to give it the name of the Monk Bat. The holes occupied by the Bats contained a great quantity of dust looking like coarse snuff, which proved to consist entirely of fragments of the hard parts of insects. Mr. Gosse appears not to have observed this Bat in houses, but he describes it as living in great numbers together in the hollows of decayed thatch-palms. He had brought to him a large basket containing a number of the Bats obtained from such a tree, and says that, on being uncovered, it “displayed a pretty scene of dusky life. The ‘pie’ of our infant days, that contained ‘four-and-twenty blackbirds’ all ready to sing, was nothing to it. Fifty Bats, all alive and kicking, were huddled into the narrow space; an arrangement which, considering their natural propensities, was probably not very disagreeable to them. I examined forty-three, a few escaping from the crowd, and if I was surprised before at the extent of their gregarious habits, I was still more surprised to find that of this number every one was of the male sex, as had been the one formerly examined.... As they huddled and crawled over each other they emitted quivering squeaks. They all displayed the extraordinary activity mentioned above, preferring to run rather than fly, though a few took to wing. In climbing, to suspend themselves, they used the thumbs or the hind-feet indiscriminately. In running along the floor, an action which they performed very swiftly, they rested on the wrists, elevating the fore-parts of the body considerably.”
THE COLLARED BAT.[232]
The Mastiff Bats certainly cannot boast of any great attractiveness in their aspect, but they must yield the palm of ugliness to a curious species described by Dr. Horsfield. It is a clumsy, heavy-looking animal, of considerable size for a Bat, measuring more than five inches in length from the tip of the nose to the root of the tail. Its body is entirely covered with a thick black skin, which is absolutely naked on the back, and has only a few short hairs upon the sides of the body, the interfemoral membrane, and the lower surface. The face and lips also have a few fine long hairs, and a curious collar of brown hairs runs round the neck. To add to the charms of the creature, the skin is thrown into thick folds in various parts of the body; the legs are thick, and terminated by clumsy feet, in which the first toe is very large, bristling with long hairs on the outside, and widely separated from the others, so as to acquire very much the character of a posterior thumb; the interfemoral membrane is short, forming a mere band between the legs, from which the tail, which is about half as long as the body, and very thick, projects for about two-thirds of its length. The head is long; the muzzle, which is truncated, projects considerably beyond the lower jaw; the ears are quite separate, triangular, with the tips rounded; the tragus is very small; the wings are long, and rather narrow, and their membrane extends down to about the middle of the shank, but springs from such a level on the sides of the body, that a deep cavity is formed on each side under the armpit, which is converted into a sort of pouch by an extension of the skin of the sides to the lower surface of the upper arm and thigh. In the pouches thus formed, and close to the armpits, the nipples are situated. There are two incisor teeth in each jaw, the upper ones strong, and implanted in well-developed and united intermaxillary bones. The upper jaw has one, and the lower jaw two premolars on each side, and there are three true molars on each side in both jaws.
HEAD OF COLLARED BAT.
(After Temminck.)
This hideous Bat was discovered in the peninsula of Malacca, and has since been found in Java, Sumatra, and Borneo. It does not appear to be abundant in its native countries, and its apparent rarity is doubtless increased by its selecting for its residence the wildest and most solitary districts in the heart of the great forests. During the day it usually retreats to the hollow trunks of trees, but sometimes takes its repose in holes in the ground or in clefts of the rocks, coming out soon after sundown, when it is seen flying heavily about the borders of the woods, or even high up above the forest in the plains.
Another curious but by no means agreeable peculiarity of this species remains to be noticed. Across the base of the neck, immediately in front of the breast, there is a great pouch, formed apparently by a fold of the skin, which receives an oily secretion from a large gland, regarded by Professor Temminck as perhaps analogous to the thyroid. In the male this gland is very broad, and divided into two lobes, and the fluid secreted by it passes into the pouch by a great number of small pores. In the female the apparatus is smaller, but more complicated; the gland is composed of two small lobes, but between these there is a membranous pouch or reservoir, in which the oily fluid seems to become concentrated, forming a brown, granular, fatty matter, which passes into the great throat-pouch through a single large opening. This secretion possesses an odour so strong as to be still perceptible after the animals have been preserved in spirits for several years; and Dr. Salomon Müller states that his artist, M. van Oort, when engaged in making a drawing from a living specimen, was affected with a headache and nausea so violent that he had much difficulty in completing his task. It appears that the fetid fluid gets diffused over the hairs bordering the throat-pouch, and thus readily passes off into the air, and spreads to a long distance round the places inhabited by the Bats, and may thus serve, as Professor Temminck suggests, to enable these creatures to find each other in the dark retreats which they frequent. This would apply to other species which diffuse a peculiar odour, although none of them seem to possess so powerful an odoriferous secretion as the Collared Bat.
