"Tools maketh man," so said Kenneth Oakley, the pre-historian. He meant that only human beings make tools of flaked stone. More generally, many species of animals make and use tools, both in nature and in natural captivity, from wasps to finches to apes, but many more do not. Few species have tool kits (repertoires of different types of tool for different purposes) or tool sets (two or more kinds of tools used in series to perform a task). Making sense of such behavioral variation is a challenge to scientists.

Tools

Definitions of tools vary (Beck 1980). In this entry, the following is used: a detached inanimate object used by a living creature to achieve a goal, typically to alter the state or position of another object. This includes constructing a nest, but not reclining on a bough, and cracking a snail with a stone but not with...