But it's this close relationship that makes the question of research on chimpanzees so sticky. In recent years, investigators concentrating on chimpanzee behavior have found other similarities between us and great apes. Like humans, chimpanzees use tools. Primatologists say that distinct populations have unique cultures. In the wild, some will carry a stone tool from place to place, a sign that they're capable of planning ahead.
Some research laboratories work with chimpanzees and language.
Other experiments show chimps have some facility with numbers and symbols. Chimps can distinguish relatives from unrelated chimps. They demonstrate self-awareness. To many, these abilities make chimpanzees uncomfortably close to humans, perhaps too close to use them in experiments. Among those who disagree with the use of chimps in research, and even their display in zoos, is an organization called the Great Ape Project.