The behavior of chimpanzees varies greatly depending on which of the two chimpanzee species is being considered – the Common Chimpanzee (Pan troglodytes), which lives north of the Congo River, and the Bonobo (Pan paniscus), which lives south. Though these chimpanzees are nearly indistinguishable anatomically – about 75-155 lbs (35-70 kg), standing at 0.9-1.2 m (3-4 ft) in height, with an average lifespan of 30-40 – their behavior couldn’t be more different.
The Common Chimpanzee is the more common and more vicious of the two. Hunting in troops, common chimps live in tribes led by an alpha male and characterized by complex social relationships, similar to the situation with humans. Among these chimp societies, as in many others, rape and murder are commonplace. Common chimps are substantially more aggressive than Bonobos, and have been known to attack and kill humans on occasion. This isn’t very difficult if the human is unarmed, as chimps have over 5 times the upper-body strength of a typical human male. These chimps are omnivorous, and have a substantial amount of meat in their diet.
In contrast to common chimps, the Bonobo species of chimpanzee is mostly vegetarian, nonviolent, matriarchial, and is famous for its sexual receptiveness. The reason for this substantial difference in behavior in not entirely known. The Bonobo chimp has proportionately longer limbs than the Common Chimpanzee, adapted for spending more time in trees, where they eat fruit. Bonobos have a slightly lighter build than common chimps. This is because they neither hunt nor fight as frequently as common chimps.
Chimpanzees of both species are highly intelligent, one of the smartest animals besides humans. Like the other great apes (gorillas and orangutans), chimpanzees are tool-users, capable of constructing their own rudimentary tools and using them in culturally specific ways. Before the discovery of tool use in chimps, it was thought that only humans were capable of using tools. Also like humans, chimpanzees are status conscious and capable of manipulation and deception. They take actions both for utility and social display. Tests on chimpanzee cognition have found that they can use symbols and can understand some aspects of language including relational syntax and concepts of numerical sequences.
Chimpanzees are capable of empathy and can produce laughter-like vocalizations, which has thrown into disrepute the quote by Aristotle that “only the human animal laughs.” Chimpanzees are one among few species that can pass the mirror test, that is, recognize a dot on their forehead upon looking into a mirror. This is considered an important indicator of self-awareness.
