Most monkeys live in tropical rainforests of Africa, Asia and Central and South America. Some, like colobus monkeys and langurs, also inhabit mountain areas. Others, such as geladas and golden monkeys, live in rocky savannas of Africa. Some monkeys, such as howlers and baboons, spend their time on the ground in savannas or wooded areas, though they can climb as well.
Many monkeys are highly social, living in groups called troops. The size of a troop varies by species, but usually it includes several adult females with young and some males. Some species, such as hamadryas baboons, mandrills and most guenons, are one-male groups, where a single male rules over a group of females and their offspring. The other kind of troop is a multi-male group.
Monkeys use vocalizations and facial expressions to communicate, as well as a long tail that they can move in various ways for locomotion. For example, howler monkeys use their deep calls to let other troops know where they are and to avoid confrontations. They howl to conserve energy, which would be spent patrolling their territories or fighting with other troops.
Most monkeys are not suitable as pets, because they require full commitment and care from their birth through old age. Moreover, the desire for pet monkeys fuels the illegal wildlife trade, contributing to species extinction and population decline in the wild. Also, monkeys are prone to developing serious diseases that can be spread to humans.