TEETH OF THE OPOSSUM.
Some of the Didelphidæ have no marsupium, or pouch, or it is very slightly developed, and in these particular kinds the young, after having left the nipples, are carried on the back of the mother, retaining their position by twining their tails around hers. The mammæ are numerous: there may be as many as thirteen, an odd one being found in the centre of the ring of the other nipples.
The Opossums are active, sly, and very intelligent in certain things, and their food consists of insects, small reptiles, birds, and eggs. Living for the most part in trees, they secrete themselves in the hollows of the branches and trunks during the daytime and sally forth in the night. They have a moderate-sized cæcum. It must be noticed that the great toe of the hind foot is well developed, has no nail, and enables the creature to grasp, and is thus very useful; and that they walk plantigrade. The ankle and leg have the same movements as in the Wombats, and the same general anatomy. If the members of the family are compared with those of the families which live in the Australian province, it will be found that they most resemble the Perameles and Dasyures. The Opossums may be divided into three groups: those whose pouch is well developed, those in which it is a mere fold, and those which have webbed feet and live in the water, like Otters.
SKELETON OF THE CRAB-EATING OPOSSUM.
THE COMMON OPOSSUM.[123]
This is a large kind, and is about the size of a common Cat, and its long, large, pointed head, ending in a naked snout, and having eyes encircled in dusky brown fur amongst the white hair and fur of the head, gives it a very cunning and thoughtful appearance. The ears are black. The tail is long and prehensile, the end being white and the rest black, and the legs and feet are brownish. It is a great climber, and uses its tail almost as much as some of its Monkey companions. Running along the branches, it will often suspend itself by its tail, and give a swing and let go, thus launching its body to a distance, and then it catches at the boughs with its feet and unclawed but prehensile hind toe-thumb. In coming down trees it uses the tail to steady itself, and to prevent too rapid a fall; and in climbing, the ever-ready tail prevents mishaps, should the clawed toes not grasp sufficiently. The natural food of this Opossum is probably vegetarian, but it is a great birds’-nester; it will eat roots and fruits, but the early settlers found it very destructive to their poultry, for it catches the birds and sucks their blood, not eating the flesh: consequently, it has been much hunted, and as the fur and skin are sometimes used, the destruction of the Opossum has been great. It is a curious creature, and seems to have gained experience in its struggle with man, and as many stories are told of its cleverness as there are about Reynard the Fox and the Indian Jackal. It will sham death in a most persevering manner, and is at the same time very tenacious of life.
The skull has strong temporal ridges, which form a sagittal crest, and the arch of the zygoma is well grown. The animal has a longer facial part of the skull and a smaller brain-case than the other Dasyures, and the brain has large olfactory or front lobes. The cerebral hemispheres are small, and there are no convolutions. This is essentially a North American animal, and is found from Mexico to the Southern States inclusive.
The female brings forth from twelve to sixteen young at a time, and her nest, which is formed of dry grass, is usually at the root of a tree or bush. When first born, the young are said not to be more than a grain in weight, and blind, naked, and shapeless. They find the teats in the mother’s pouch, unless she places them on to them with her mouth, and they cling on so as not to be separated except by violence. In about five days, so rapid is their growth, they have reached the size of a Mouse, and all their parts are developed. They then leave the pouch, and return to suckle and when danger appears. During this time the female shows great attachment to her young; and Mr. Waterhouse, from whose work these descriptions are taken, states that she will suffer any torture rather than permit the pouch to be opened.