(PhysOrg.com) -- Many animals are known to use tools, but chimpanzees (our closest living relatives) show the most varied and complex use of tools, and the males in one group of chimps have even been observed using sex tools to attract a mate.
The definition of "tool" varies, but most scientists recognize objects as tools if they are inanimate objects outside the body of the user, if they are used to alter the environment in some way or to gain information about it, and if they are modified in some way in function, form or position. Chimpanzees were first observed using tools by Jane Goodall in 1960, when she documented chimps using blades of grass to extract termites, and chimps are now known to use a "tool kit" of around 20 tools, with the tools in the kit varying from one colony to another.
Researchers working in Tanzania have observed male chimpanzees plucking and breaking the dry, brittle leaves in front of their visible erection, and using the rasping sound to attract the attention of a female. If she is interested, the behavior is followed by mating. The use of leaves in this way has not been seen in other chimp groups, but chimps everywhere have been seen to use tools and combinations of tools in complex sequences to attain their goals, which may involve food, social rituals, or in this case, sexual desires.
In an essay in Science, primatologist and university lecturer in biological anthropology, Dr. William C. McGrew from the University of Cambridge, described the latest findings on tool use in chimpanzees. He said the leaves used by the Tanzanian chimps fit the definition of a tool because the chimps are using an external object to obtain a specific goal, which is to interest the female chimp in mating.
Dr McGrew is the author of the book “The Cultured Chimpanzee: Reflections on Cultural Primatology” and hundreds of scientific publications on non-human primates.
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More information: William C. McGrew, Chimpanzee Technology, Science 30 April 2010: Vol. 328. no. 5978, pp. 579 - 580. DOI:10.1126/science.1187921