This enables a monkey to grasp small food items. Most kinds of New World monkeys have thumbs that are only partly opposable. Their thumbs also do not move so freely as those of Old World monkeys. Among Old World monkeys, colobus monkeys have no thumbs. The feet of most monkeys are larger and more powerful than their hands.
All monkeys have five toes on each foot.
Marmosets and tamarins have claws on their fingers and toes, except for their big toes, which have a nail. All other kinds of monkeys have flat or flattish nails on all their fingers and toes. Most monkeys that live on the ground have a shorter tail than do most that live in trees. Arboreal monkeys may have a tail longer than their body. They use their tail for balancing on tree branches.