In 1960, Jane Goodall observed a chimpanzee stripping leaves from a twig and inserting it into a termite mound to extract termites — the first documented instance of tool manufacture by a non-human animal. It prompted Louis Leakey’s famous remark: « Now we must redefine tool, redefine Man, or accept chimpanzees as humans. » Six decades of subsequent research has revealed that chimpanzee tool use is not merely present but culturally diverse — varying between populations in ways that can only be explained by social learning.
Cultural Transmission Evidence
Nine geographically separated chimpanzee communities have been studied continuously for more than 20 years. Each community displays a distinctive toolkit — specific tools used, materials chosen, techniques employed — that cannot be explained by environmental availability alone. Termite fishing sticks are present in some communities where termite mounds are available but absent in others with identical mound access; nut-cracking with stone hammers and anvils appears in West African populations but not equivalent East African ones despite nut availability.
Crucially, techniques transfer when individuals move between groups. Immigrant females who bring novel tool techniques to a new community are observed, imitated, and eventually adopted into the community’s toolkit — precisely the pattern expected of cultural transmission. Experimental studies demonstrate that chimpanzees copy tool techniques from social models and maintain those techniques even when discovering more efficient alternatives, a conservatism parallel to human cultural inertia.
What Tool Use Reveals About Cognition
Tool manufacture requires forward planning, causal understanding of material properties, and fine motor control. Chimpanzees select raw materials based on flexibility, length, and texture appropriate to the target tool’s function — often traveling to preferred material sources before beginning manufacture. Nut-cracking, which takes juveniles up to 10 years to master, requires understanding hammer weight, anvil stability, and force calibration that must be learned through years of practice and observation.
New research published in 2024 documents chimpanzees making composite multi-component tools — assembling separate pieces into a functional implement — a capability previously considered a threshold marker of hominid cognitive evolution. The finding revises timelines in evolutionary psychology and raises fresh questions about what cognitive capacities genuinely separate humans from our closest living relatives.
