282 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1949 
the third time I offered a certain nut to a very friendly wild squirrel, 
it took the nut, opened it, and dropped it, perhaps to show me that 
the nut was not fit to eat. 
TRANSPORTATION OF OBJECTS 
The need of transporting food, nest materials, or young, and occa- 
sionally objects that apparently are taken for ornamental purposes 
or merely because the animal likes them, have been solved in various 
ways. Most animals carry objects in their mouths to some extent, 
just as a dog carries a stick or ball, but there are a number of ways 
in addition to this: for example, some of the Old World monkeys 
(Macaca and others) have cheek pouches that open inside the lips, 
but outside the jaws, in which they are able to store food, which must 
be a great convenience to them when they are trying to obtain their 
share in the presence of other greedy monkeys. They then grab what- 
ever food they can, put it in their cheek pouches, and eat it at their 
leisure. Monkeys with food in their pouches sometimes look as though 
they had mumps on one or both sides. Internal cheek pouches are 
found in a number of other animals such as the chipmunks (Tamas 
and Hutamias) and hamsters, which use them as shopping bags or 
baskets into which to place food to carry it home to the den where it 
is stored for future use (pl. 1, fig. 2). Another type of cheek pouch is 
the external one which is fur-lined. This is present only in a few 
North American forms such as the pocket gophers (Geomys, Thomomys, 
and related genera), the pocket mice (Perognathus) and kangaroo rats 
(Dipodomys and Microdipodops). Their pockets open outside the 
mouth, the skin of the face being folded inward to form the pockets. 
The pockets can be turned inside out to clean them, then pulled back 
into place by a special muscle. The owners of these pockets carry 
food, nest material, and even earth in them. 
We are so accustomed to seeing mother cats carry their kittens 
by grasping the skin at the back of the neck that we commonly think 
of this as being the principal way of carrying young; however, there 
are many other methods. The mother squirrel grasps the skin of 
the baby’s abdomen in her lips or teeth so that the little one hangs 
in an inverted position beneath her head, grasping her neck with its 
hands and feet and curling its tail around her neck, thus aiding in 
the carrying and leaving no dangling appendages to interfere with 
mother’s hands and feet in her travels through the trees. Baby 
monkeys cling tightly to the mother in most cases, but the white- 
tufted marmoset (Callithrix jacchus) mothers generally carry the 
babies only when nursing them; the rest of the time the fathers carry 
them (pl. 8, fig. 1). They cling to his long fur and ride on his back or 
under surface and hold on so securely that he can make leaps through 
the trees without dislodging them. Baby gibbons cling to the mother 
