Natural History

There are 4 recognized species of great apes: gorillas (Gorilla gorilla), orangutans (Pongo pygmaeus), common chimpanzees (Pan troglodytes) and pygmy chimpanzees or bonobos (Pan paniscus). Among the common chimpanzees (the focus of this article), there are 3 recognized subspecies: P. t. troglodytes, P.t. schweinfurthi, and P.t. versus (the latter being the subspecies found at the Chimpanzee Conservation Center).

Chimpanzees are native to central Africa. They are found in 21 countries, and are at their highest concentrations in rainforests. Unfortunately, due to logging many of these forests and their chimp populations have been segmented and isolated, which could eventually lead to inbreeding or even local extinctions. Logging roads also allow increased travel deeper into the forests for poachers.

Chimps have black hair (occasionally tinted with silver hairs) and pinkish to black, bare skin on their faces, ears, palms of their hands and the soles of their feet. Infants' skin is lighter. Their hair is coarse like a human's, and may thin or turn gray with age. Unlike humans, the sclerotics of their eyes are brown rather than white (with a few rare exceptions).

Chimpanzees' arms are longer than their legs. They easily climb high in the trees and can swing from one to another by brachiating through the branches. They usually travel longer distances on the ground. Known as "knuckle walkers," they walk on the soles of their hind feet and the knuckles on their hands. The first two segments of their fingers are heavily calloused and protected with thick tissue. This adaptation prevents them from opening their hands as widely as a human can. Chimps can walk upright, but do so awkwardly, and only for short distances. Chimps have opposable thumbs, which are smaller than the thumbs on humans. Their opposable big tows help them to grasp objects and climb.

Chimpanzee males are larger than females, and slightly heavier. Chimps are much larger than most people realize. Many people are accustomed to seeing chimpanzees on TV, in movies, on greeting cards or in circuses. As a result, most of us have only been exposed to babies and juveniles. This is because they are smaller, cuter, easier to handle and more submissive. An adult chimpanzee can grow to be more than 175 pounds in captivity and about 4 feet tall when standing upright. At seven times the strength of a human, and with a very independent mind and temper, they do not make suitable pets. In captivity, chimps may live in excess of 60 years, thus requiring nearly a human lifetime of care. Sadly, the vast majority of chimpanzees kept as pets or entertainers, in private or commercial ventures, have historically ended up in biomedical facilities, and only a few in zoos. Most zoos are not eager to take in chimpanzees because due to their exceptional intelligence and strength, they can be very destructive to their enclosures, requiring highly specialized facilities. Until about the last 25 years, most zoos kept their primates in cement buildings with iron bars where they wasted away from boredom and poor living conditions. Chimpanzee sanctuaries like the Center for Chimpanzee Conservation are a relatively new idea.

Like humans, chimpanzees are omnivores, and eat many kinds of foods, including fruits, nuts, flowers, seeds, leaves, a number of insects and occasionally even small to medium sized animals. Some chimpanzee communities are known for fashioning and using simple tools to procure their food. In Gombe, chimpanzees prepare and use sticks to "fish" for termites by poking them into their mounds and waiting for them to grab on. In other communities chimps use rock/log "hammers and anvils" to crack nuts.

Chimpanzees live within large communities, traveling in smaller groups whose members are constantly changing (within the community). The males of the community have a linear hierarchy; the most dominant being know as the alpha male. Females also have a dominance hierarchy, though it is generally much more fluid, and all females are subordinate to adult males.

Females become sexually attractive to males at around age 10 or 11. Sexual swellings on the rump indicate a receptiveness to mate. Some females may be more attractive to males than others (the reason often being a mystery to human observers). There is usually a 2-year period of adolescent sterility before a female finally conceives. In captivity, males have been known to induce pregnancy as young as 4 years old, though not so young in the wild. Often several males may mate with a female during her cycle. Even juveniles may use the opportunity to "practice." Sometimes a dominant male may keep a female to himself and attempt to fend off the others. A male may even sense a female's approach to sexual receptiveness and lead her away from the group for a consortship.

Chimpanzees communicate with a wide variety of calls, gestures and postures. Food calls alert others to newly found food sources. Pant hoots serve as long distance greetings. Chimpanzees even laugh during play. Of all the social behaviors in chimpanzees, grooming is probably one of the most important. It serves to improve relationships between individuals and calms nervousness and tense situations. Chimpanzees are so gentle and precise when grooming that they may remove specks from each other's eyes and tiny splinters in the skin.

Also like humans, chimpanzees can be very aggressive. Males put on energetic displays; bristling all the hair on their body, thrashing through the brush, throwing rocks and shaking tree limbs in an effort to improve or demonstrate their status of dominance in a group. Groups have been known to wage systematic "wars" on other groups, decimating its members. Even cannibalism has been observed.

However, chimps are also very gentle, affectionate creatures. Chimps laugh, kiss, and hug each other and form bonds of friendship. They even mourn the loss of loved ones. The bonds between a mother and infant are intense. Bonds between a mother and female offspring often last a lifetime, and older generations may assist in the upbringing of the younger. This fact makes the story of our orphan chimps at CCC all the more tragic, as many of them probably saw their own mothers killed by poachers.