Dr. Jane Goodall’s work showed that what we considered the exclusive domain of humans was shared with our chimpanzee next of kin.
Photo: © M. Nichols
Chimpanzee intelligence is rich and complex. In attempting to describe how sophisticated chimpanzee intelligence is some people erroneously liken it to the intelligence of a five-year-old human child. This falls grossly short of the realities.
Chimpanzee intelligence is as sophisticated and effective in their world as human intelligence is in our own world. Their ability to mimic the abilities of five-year-old human children merely indicates their infinite capacity to adapt.5 It says nothing about any limits on their ability to learn, to think, and to act from their own reason and adult status in their society.
Chimpanzee adults exhibit mature intelligence, while chimpanzee children will often act without “thinking” about consequences.5 Some chimpanzees are slow; others are brilliant. The range of intelligence of chimpanzees varies, just as ours does.
Their ability to learn new skills and teach their young is remarkable. Like us, they can do everything to survive in their world with the specific challenges it presents to them.1
The complexity of their intellect is matched by their rich and complex emotional repertoire. They feel, and they express those feelings. They use feelings as yet another way to navigate through their lives and relationships. Their feelings range from anger to exhilaration, from humor to despondence – and every other emotion we know.1
Because humans and chimpanzees evolved from a common ancestor and co-existed in Africa over millions of years (read Our Primate Family), it is no surprise that we share common traits in intellect and emotion.2
Chimpanzees have large, complex brains whose physical structure is similar to human brains. Chimpanzees are curious, and learn from observation and imitation. They have long-term memories and, like people, are either left-handed or right-handed.1
Although not identical to human language, chimpanzees have a complex system of communication that uses a variety of body language, facial expression and calls, grunts, gestures, and other specific sounds. Each individual chimpanzee can be identified by his or her own “pant-hoot.”8
Learning and intellect
It was once thought that only human beings were capable of making tools, but primatologist Dr. Jane Goodall observed free-living chimpanzees in Africa using sticks to fish termites out of mounds, and making use of other objects.7 Tool-making is culturally influenced; chimpanzees in different parts of Africa make and use tools differently, showing that tool use is a learned behavior.4,7 Chimpanzees also make their own toys and devise their own games. These observations drastically changed our thinking about the uniqueness of Homo sapiens.3
Chimpanzees learn to use certain plants as medicine. They chew on the leaves of aspilia plants, which contain an oil-based drug that kills parasitic worms and bacteria. When experiencing stomach pain, they drink the juice of vernonia shoots, which function as an antibiotic.1
Field studies and observances in the wild have shown that chimpanzees know how to plan ahead and communicate with each other in order to act collectively, whether confronting predators, discovering a food cache, or hunting smaller mammals.6
In captivity, chimpanzees can also be taught to do many things. Their incredible ability to learn tricks and perform has unfortunately resulted in their being exploited by the entertainment industry.
Chimpanzees laugh when they play and cry when they grieve. They experience and express joy, anger, jealousy, compassion, despair, affection, and a host of other emotions.1 Touching and grooming are vital to maintaining stable relationships and keeping the peace within the community group.4
Conversely, chimpanzees who are deprived of normal living environments and/or social interaction often succumb to depression and other emotional illness, from which many never fully recover. As intelligent social animals, they suffer intensely from confinement and isolation.
Part of what we know about chimpanzee thoughts and feelings comes explicitly from chimpanzees themselves. Although their anatomy prevents them from producing the same sounds that create human speech, many can learn American Sign Language (ASL) and express themselves that way.2 (Gorillas have also been taught sign language.)
Through sign language, chimpanzees express complex emotions and concepts, give logical names to objects, and engage in genuine conversation with human beings.2
Chimpanzees have also been taught to communicate and solve test problems using computers equipped with keyboards that use symbols instead of letters.2 This ability to use mutually understood symbols in a relevant context is yet another example of their high intelligence.
It is important to remember that chimpanzee intelligence cannot and should not be measured exclusively by human-based tests. However similar our species are, chimpanzees have evolved – physically and intellectually – to suit their own environment and needs, not ours. Their abilities are relevant to their specific circumstances, and should always be understood in the context of what best serves the chimpanzees themselves.
…[T]he saga of some of these animals provide stories of devoted, intelligent, and marvelously strong individuals who have had to deal with challenges for which evolution has not fully prepared them. I have followed the lives of many … for fourteen years. I have watched Lucy, Washoe, Ally and Nim at various stages … I have also observed the changes that these apes have wrought on the scientists and other people whose lives they have touched. I have both watched and participated in the debate that has continued… about what these experiments mean… What I have seen has been disquieting, not only because of the tragic chemistry between human and chimp but also because of what I have been forced to perceive as the frail underpinnings of science and human judgments - including my own.
— Eugene Linden, Silent Partners, The Legacy of the Ape Language Experiments, pp. 9-10
 Preston-Mafham, Rod and Ken. Primates of the World. New York: Facts on File, 1992.
 Ross, Ben. “The Human-Chimp Connection,” Available at www.benross.net/chimp.htm
 Stanford, Craig. (1995) “Chimpanzee Hunting Behavior and Human Evolution,” American Scientist, (May-June) : 256-261.
 Briggs, Helen. (2001) “Cultural Habits of Chimps,” BBC News Online, Aug. 10, 2001. Available at http://news.bbc.co.uk/1/low/sci/tech/1484261.stm
 Bright, Michael. Intelligence in Animals, London: Toucan Books/Reader’s Digest, 1994.
 “Learn About Free-Living Chimpanzees.” Chimpanzee and Human Communication Institute (2004). Available at http://www.friendsofwashoe.org/learn/free_living/
 “Tool Use, Hunting, and Other Discoveries” Jane Goodall Institute. Available at http://www.janegoodall.org/chimpanzees/tool-use-hunting-other-discoveries
 “Communication.” Jane Goodall Institute. Available at http://www.janegoodall.org/chimpanzees/communication