at Gombe. Present at Goulougo. Absent at Mahale. tickle with hand or foot See tickle. tickle with mouth See mouth. tilt head Incline head to one side while standing quadruped, to solicit play, or to look above. 8. See video. tip head Goodall Head tip: a threatening gesture. Head is jerked very slightly backwards, at the same time chin is raised. The performer faces the individual being threatened and the gesture is usually accompanied by a cough bark and often an arm raise. Plooijs Tip. Also in bonobos. T 190 tool composite Tongo Study site of Pan troglodytes schwein-furthii within Virunga National Park, Democratic Republic of Congo. Research done from 1987 to 1990. tool Object extracted or detached from environment and used to obtain benefits or pleasure, in