Most of the Old World monkeys, for example, possess large cheek-pouches, in which, after eating a meal, they can carry away nearly enough food for another. No doubt you have often seen a monkey with its cheeks perfectly stuffed out with nuts. But in the American monkeys these pouches are never found.
Then no American monkey has those bare patches on its hind quarters, which are present in all the monkeys of the Old World, with the exception of the great apes, and which are often so brightly colored. And, more curious still, no American monkey has a proper thumb. The fingers are generally very long and strong; but the thumb is either wanting altogether, or else it is so small that it cannot be of the slightest use.
PHOTOGRAPHIC PORTRAITS OF MONKEYS.
| 1. Young Orang-utan "Dohong." | 2. Barbary Ape. |
| 3. Japanese Red-faced Monkey. | 4. White-faced Sapajou. |
| 5. Siamang Gibbon. | 6. Chimpanzee "Polly." |
All lived in the New York Zoölogical Park.
Spider-Monkeys
Perhaps the most curious of all the American monkeys are the spider-monkeys, which look very much like big black spiders when one sees them gamboling among the branches of the trees. The reason is that their bodies are very slightly built, and their arms and legs are very long and slender, while the tail is often longer than the head and body together, and looks just like an extra limb. And indeed it is used as an extra limb, for it is prehensile; that is, it can be coiled round any small object so tightly as to obtain a very firm hold. A spider-monkey never likes to take a single step without first twisting the tip of its tail round a branch, so that this member really serves as a sort of fifth hand. Sometimes, too, the animal will feed itself with its tail instead of with its paws. And it can even hang from a bough for some little time by means of its tail alone, in order to pluck fruit which would otherwise be out of its reach.
Owing partly, no doubt, to constant use, the last few inches of this wonderful tail are quite bare underneath—without any hair at all. It is worth while to remember, just here, that while in many American monkeys the tail has this prehensile grasp, no monkey of the Old World is provided with this convenience.
When a spider-monkey finds itself upon level ground, where its tail, of course, is of no use to it, it always seems very uncomfortable. But it manages to keep its balance as it walks along by holding the tail over its back, and just turning it first to one side and then to the other, as the need of the moment may require. It uses it, in fact, very much as an acrobat uses his pole when walking upon the tight rope.