Our Closest Living Relatives Chimpanzees are more closely related to humans than they are to gorillas. Chimpanzees and humans share 99 percent of their genetic composition. Chimpanzees are highly intelligent, probably more so than human-based tests are able to measure. They make and use tools, cooperate with and learn from each other, and can learn various forms of expression and communication, including American Sign Language and computer symbols. Chimpanzees also have good memories.
Chimpanzees now occupy only a fraction of their former territory.
Chimpanzee habitats, already small and isolated, are being further destroyed by increased commercial and agricultural development. The U.S. Department of the Interior also lists them as endangered. There are approximately 2,000 captive chimpanzees in the United States. Many are the offspring of chimpanzees captured in the wild before 1973, when the United States agreed to abide by an international treaty prohibiting the capture and importation of wild chimpanzees. Captive Breeding Any increased use of chimpanzees in U.S. laboratories must rely on captive breeding.