Figure 2.

Sequence of elements exhibited by chimpanzees in termite fishing. The horizontal axis indicates progression of elements in a tool using sequence. The vertical axis represents different behavioural elements which are numbered from 1 to 10 (1, termite gathered by hand; 2, termite swept from tool; 3, termite eaten directly from tool; 4, fray end of tool to brush; 5, reduce length; 6, straighten brush fibres; 7, failed insertion; 8, insert/extract fishing probe; 9, probe to perforate; 10, reverse orientation of tool). The arrangement and repeated cycles of element strings can be seen in the adult sequences (Theresa, Sarah). Theresa exhibited strings of elements associated with the direct mouthing technique to gather termites, whereas Sarah repeated strings associated with the sweeping technique. Although the same behavioural elements are present in the sequences of their juvenile offspring (Leakey, Samantha), the execution of element strings is not as consistent.