Tool use was once thought to be a strictly human behaviour, but it is now known that many kinds of animals use tools. These include crows, dolphins and - of course - primates such as chimpanzees. Some animals, sea otters for one, have a favourite tool that they carry about with them. Others find nearby articles such as stones, twigs or thorns, which they use and then discard. Advanced use comes about when tools are used in combination, as when chimps use both a hammer and an anvil to crack kernels.

More...