Chimpanzee, an ape of equatorial Africa. It is the most intelligent of all apes, capable of using tools and of learning complicated tasks. Wild chimpanzees use sticks and blades of grass to extract termites from their nests. Chimpanzees can be taught to eat with a knife and fork and to ride a bicycle. Some chimpanzees have been taught to form sentences by using sign language or by pressing geometric symbols on a computer keyboard.

The chimpanzeeThe chimpanzee walks on all fours but can also walk upright.BonobosBonobos are small primates closely related to the chimpanzee.How Are Bonobos and Chimpanzees Related?

Scientists once considered the bonobo to be a small subspecies of the chimpanzee. In fact, bonobos were known as pygmy chimpanzees. Today, however, the bonobo and chimpanzee are considered separate species of great apes.

At first glance, bonobos look much like chimpanzees, but there are some differences. Bonobos have smaller, rounder heads, and their faces are blacker than those of chimpanzees.

Bonobos, like chimpanzees, form communities of males and females. But, whereas the males lead chimpanzee communities, bonobo societies center around the females.

How Do Chimpanzees Use Tools?

Chimpanzees make and use simple tools more than any other creatures except human beings. For example, chimpanzees strip the leaves from plant stems and use the stems as tools to catch termites to eat. They also use leaves as “sponges” to soak up water to drink, and as “tissues” to clean their bodies. Some chimpanzees use stones as “hammers” to crack open nuts.

Young chimpanzees use sticks or stones to tickle themselves in hard-to-reach places. Chimpanzees wave sticks in the air to frighten or ward off enemies. Sticks are also used as hooks to pull down branches so the animals can reach the fruit on them.

Chimpanzees practice making and using tools from the time they are very young. They imitate the actions of adults, getting better over time. What begins as simple play becomes an important skill in later life.

How Do Chimpanzees Communicate?

Chimpanzees communicate using barks, grunts, and screams. When they find a large food supply, the apes jump through the trees, hoot loudly, and beat on tree trunks. This lets all other chimpanzees within hearing distance know there is food available.

Chimpanzees also communicate with body postures, facial expressions, and hand gestures. Chimpanzees greet each other by embracing or by touching various parts of the other's body. Their facial expressions show many emotions, including excitement, fear, and rage. A chimpanzee, especially a male, will sometimes scream and wildly run around to intimidate another chimpanzee—this noisy show is known as a “display.”

Since the 1960's, scientists have worked to teach chimpanzees sign language and other types of language. In Atlanta, Georgia, a chimpanzee named Lana learned to use symbols on a computer keyboard to ask for food, company, and music.

How Are Chimpanzees and Humans Alike?

Scientific evidence suggests that chimpanzees (and their close cousins, the bonobos) are more closely related to humans than is any other animal. Not only are they our nearest relative, we are theirs. We are a closer relative of the chimpanzee than is the gorilla, orangutan, or any other kind of primate.

Scientists believe this because human and chimpanzee DNA are nearly identical. DNA is a molecule that determines hereditary traits and affects how organisms look and behave. DNA is found in the cells of all animals. Closely related animals share similar DNA.

Even without examining their DNA, it is easy to see that chimpanzees are closely related to humans. Both have similar body structures. Both also have many complicated behaviors, such as using tools and communicating their emotions.

Why Do Chimpanzees Groom Each Other?

Adult chimpanzees spend about an hour each day in a friendly social activity called grooming. During this time, two or more chimpanzees sit and pick through each other's hair. They remove dirt, insects, leaves, and burs (the seeds of certain plants) from each other.

In addition to helping keep each other clean, grooming reduces tension among group members. Chimpanzees are sociable animals who seem to need physical contact, and grooming helps satisfy this need. It also strengthens ties between group members. Sometimes as many as 10 chimpanzees will take part in these peaceful, relaxed grooming sessions. Often a grooming group will be made up of a mother and several of her offspring of different ages. Adult males may also groom one another.