i8o CHILDHOOD OF ANIMALS 



band of muscle so that the female can shut it up to an extremely 

 small hole or open it out widely. For a period lasting from a week 

 in the smaller ones to several weeks in the larger animals, the 

 infant remains motionless inside the pouch firmly attached to the 

 nipple. It is not even able to suck, but has to have the milk 

 squirted into its mouth by the mother. It then acquires a hairy 

 coat, leaves the nipple, and begins from time to time to push its head 

 out of the opening of the pouch and takes its first view of the world 

 (Fig. 33). Soon after its first appearance it begins to nibble, and 

 as the mother stoops down to crop grass or hay, the head of the 

 youngster is thrust out and it also begins to pick at food. Gradually 

 it learns to push out its head more and more, and even its fore-paws, 

 but as soon as the mother is startled and sits up to look towards 

 the source of danger, the young one retreats into the pouch,' leaving 

 only its head with bright twinkling eyes visible. Still later on the 

 young one occasionally comes out of the pouch altogether, and 

 feeds on its own account, hopping near the mother. At the first 

 sign of danger, however, the mother stoops down, opens the pouch 

 widely, and the young one bolts into it head first, and then wriggles 

 round until it has reached its favourite position with only the head 

 protruding. Kangaroos give birth only once a year, and long after 

 the young one is much too big to enter the pouch it keeps with its 

 mother, and tries to suckle by thrusting its head into its former 

 home. In some of the omnivorous and carnivorous marsupials, as, 

 for instance, the thylacine, the pouch opens backwards, and these 

 are quadrupedal in gait, not hopping on their hind-legs and 

 tail like the kangaroos ; in others it is present only in the form of 

 temporary folds of the skin, and in others again there is no trace 

 of it. 



All the marsupials, except perhaps the fierce thylacine and the 

 Tasmanian devil, are preyed on by other marsupials, or by large 

 eagles and other birds-of-prey, and escape by flight. If the young are 

 small enough they are carried in the pouch of the mother, or run off 

 at her heels. In a few cases, however, especially in arboreal forms, 

 the young are carried on the back of the mother. The phalangers 

 leap rapidly from bough to bough, or run up almost vertical branches 

 with the greatest ease, and the females are often to be seen with one 

 or more young clinging to their fur. The little koala, or tree-bear 

 (Fig. 34), a gentle, inoffensive creature, carries its single cub on its 

 back. The American woolly opossums have long tails, the lower surface 

 of which is scaly and used for grasping branches. The females carry 



