These tails help them leap from tree to tree. Monkeys build their homes in very tall trees. Many monkeys live in groups. This makes them less able to be caught by predators. These monkeys are so intelligent that scientist say that they have their own hand signals to warn each other of preditors.
Monkeys are very clean animals they groom each other.
If the younger monkeys were harmed or fall behind the group they will be left there. The leader which is usually a male is responsible for finding a place to get food. The group must move in several case because of the lack of food. Most monkeys do travel in groups but in some cases they don't. For example gorillas do not they separate when they are old enough to take care of themself.