Chimpanzee

Chimpanzees share approximately 98.7% of human DNA — the closest living relative we have. Every few years, a behavior previously claimed as uniquely human is documented in chimpanzees: tool use, cultural transmission, self-recognition, empathy, political alliance-building, and warfare. The gap between human and chimpanzee cognition continues to narrow as research improves.

Facts you didn't know

• 1

  Chimpanzees wage war. Organized, lethal raids on neighboring groups — with coordinated patrol parties, ambushes, and systematic killing — have been documented at multiple long-term research sites. The behavior is not a response to human food provisioning; it occurs in undisturbed populations.

• 2

  Chimpanzee communities have distinct cultures. Different groups use different tools, make different gestures, and have different food preferences — and these differences are learned and transmitted between generations, not genetic. A chimp from one community doesn't automatically know the tools another community uses.

• 3

  Chimpanzees remember the faces of individuals they haven't seen for decades. Research has confirmed that chimps retain individual recognition across periods of over 25 years — comparable to human long-term facial memory.

• 4

  Chimpanzees demonstrate inequity aversion — they reject rewards they would otherwise accept if they observe another individual receiving a better reward for the same effort. A chimp happily taking cucumber slices will throw them back when it sees another chimp receiving grapes for the same task.

• 5

  Chimpanzees in West Africa have been using stone tools — hammer stones and anvils for cracking nuts — for at least 4,300 years, confirmed by archaeological excavation. This is the oldest documented tool use by non-humans.