Sergio Valdez, age 8, of Flagstaff, Ariz., for her question:

ARE APES LARGE MONKEYS?

Many people confuse apes with monkeys. The two groups of animals, however, are completely separate and they differ in a number of important ways. Apes are definitely not just large monkeys.

Monkeys have tails and seem less intelligent than apes. The great apes are much larger and have longer fingers and toes.

Both monkeys and the great apes walk on all fours. But the great apes do so in a semi upright posture, supporting the front part of their bodies on their knuckles.

There are four kinds of apes: chimpanzees, gibbons, gorillas and orangutans. All four have hairy, tailless bodies and arms that are longer than their legs. They also have large brains and rank as the most intelligent animals next to human beings.

Also, apes resemble human beings in body structure more than any other animals do. They have similar bones, muscles and organs.

But human beings also differ from apes in many ways. As an example, human beings have longer legs and less hair on their bodies. Humans also have a more highly developed and complex brain.

Apes are divided into two groups by the scientists, based chiefly on size. Smallest of the four is the gibbon. He is called a "lessor ape." Chimpanzees, gorillas and orangutans are called "great apes."

Largest is the gorilla.

Apes live in tropical Africa and Asia. All of the apes, except gorillas, eat chiefly fruit. Gorillas eat mainly ground plants, such as wild celery and bamboo shoots.

The number of apes in the world is decreasing because people hunt them to sell to zoos and research centers. In addition, farms and even cities have replaced many of the forests where apes once lived.

In a scientific classification, apes are shown to belong to the order Primates.

Gibbons live in the tropical forests of Southeast Asia. They spend most of the time in trees. Gibbons form family groups that are made up of a male and a female together with their young.

Orangutans live in the tropical forests of Borneo and Sumatra and they spend their time largely in trees also. Orangutans usually travel alone, but a female and her single infant will travel together.

Chimpanzees are from the tropical forests and wooded, grassy plains of Africa. They live both in trees and on the ground. Chimpanzees travel in bands that consist of males and females of all ages. The bands vary in number and very often change members.

Gorillas are from the lowland and mountain forests of Africa.

They make their homes primarily on the ground and they travel in groups of about 15 males and females of all ages. Older male gorillas develop a patch of white or silvery hair on their backs. One of these males, called silverbacks, leads each group.