There are more 300 species of primates in the worldfrom humans and apes to monkeys and prosimians ("premonkeys"). Several primate species have been discovered in Brazil and Madagascar in recent years.
The smallest primate is the pygmy mouse lemur, which can fit in the palm of your hand. The largest—the gorilla—can weigh more than 400 pounds. Most primates live in warm climates, and most depend on forests for their survival.
The most obvious differences between apes and monkeys are: apes don't have tails, and they are generally larger than most other primates. Like most rules, this one has exceptions: some monkeys lack tails and some are large. Gibbons, considered to be lesser apes, are smaller than some monkeys. Apes rely more on vision than smell, and their noses are short and broad, rather than snoutlike. Apes are capable of creating tools and using language. They have complex social lives and are capable thinkers and problem-solvers.
gorillas, chimpanzees, orangutans, and bonobos live in Africa and Asia
gibbons and siamangs live in Asia
Old World monkeys: baboons, macaques, and colobus monkeys live in Africa and Asia; New World monkeys: marmosets, tamarins, and capuchins live in South and Central America
lemurs, lorises, and tarsiers live in Africa and Asia
Because gorillas and humans are so closely related, most diseases can be transmitted from humans to gorillas and vice versa. This is the reason for the glass enclosures at the National Zoo's Great Ape House. The glass prevents any exchange of disease between visitors and gorillas.
In addition, infant gorillas receive the same inoculations as human babies. They also receive tetanus, and rabies inoculations throughout their lives.