Monkeys are primates of the Haplorrhini suborder and the simian infraorder, either Old World monkeys or New World monkeys (excluding apes and humans). They live in tropical rainforests, savannas, mountain habitats and other climatic regions throughout the world. Some, like geladas and golden monkeys, are mountain dwellers; others, such as the Japanese macaques of the snow-covered country, find hot springs to spend their winters sitting in (like a primate Jacuzzi).
Most monkey species live in troops with related females and their young, with a single male or several (as in hamadryas baboons, mandrills, most guenons and langurs). Like humans and other apes, they are highly social and have a menstrual cycle, although sexual activity is usually confined to the period around ovulation.
Unlike some other primate groups, such as anteaters and lemurs, all monkeys are able to climb trees. Some monkeys use their tail for balance when moving from branch to branch, but most are limber and can move quickly between tree tops. They can even jump from one tree to another over considerable distances.
Monkeys are curious creatures that get into everything. They also tend to be destructive, biting and screaming. Moreover, monkeys need much more space than most homes can provide and cannot be effectively toilet trained. In addition, they can carry hepatitis and other diseases that are harmful to humans. Because of these problems, most monkeys should never be kept as pets. However, if you decide to take on this responsibility, check local laws first, as some states ban monkeys completely and others might require permits or impose certain conditions for keeping them.