Monkeys are mammals belonging to the order of primates. There are about 260 species. Monkeys native to the Americas have prehensile tails. Monkeys native to Africa and Asia do not, but they have cheek pouches for storing food and rump pads.
Monkeys range in size from 5-inch-tall pygmy marmosets weighing about 4 ounces to mandrills, which average 77 pounds in weight and 3 feet in height. Most monkeys live in forests and woodlands, but some species live in savannas and mountainous areas. Monkeys live in groups called tribes, troops, cartloads or missions and move from place to place as they search for food.
Monkeys are highly sociable and intelligent. They express peaceful intentions by grooming each other. When monkeys grin, yawn, bob their heads or pull their lips, they are expressing aggression. Some species form monogamous pairs; in others, the strongest male leads a group and mates with multiple females.
Monkeys enjoy fruit such as bananas, but they also eat nuts, seeds and flowers. Some monkeys also eat eggs, insects, birds and lizards. Capuchin monkeys use rocks to smash nuts and use sticks to probe crevices for food and to club snakes. If monkeys do not have enough to eat, the females stop mating until conditions are better.