Most of them are omnivores, eating plant or animal food. There are different ways to choose food and feed. For example, monkeys are good at picking bugs in tree holes or crevices. Orangutans eat a lot and spend most of their time foraging.

Different kinds of monkeys eat different foods, but mainly fruits, leaves of plants, seeds, nuts, insects, spiders, eggs of animals and small animals. Most monkeys are vegetarians, but baboons occasionally eat meat, and they even steal the young of chimpanzees or other animals.

Even so, baboons don't hunt animals as well as lions and wild dogs. Langurs mainly eat leaves and other plant parts, but they also like fruits, flowers, seeds and insects. Besides fruits, baboons in West Africa also eat grass, tree trunks, insects, eggs and lizards.

Extended data:

The reason why the monkey's ass is red:

Monkeys like to sit very much, so their buttocks often rub around on the ground, and their skin is exposed after their hair is worn off. Part of the skin on the buttocks is called sexual skin, and many blood vessels pass through it.

It is usually inconspicuous, but in estrus, due to the increase of androgen and the acceleration of blood circulation, the blood vessels on the skin of the whole body, especially the blood vessels on the skin and the blood vessels on the face, are obviously exposed, and the buttocks are red.

This is a courtship signal sent by the male monkey to the female monkey, and the female monkey will also be in estrus after seeing it. Monkey, big monkey, his ass is bright red when he is in estrus. Some monkeys live in trees.