Door slamming: Tool-use by a captive white-handed gibbon (Hylobates lar)

Abstract

Gibbons often accompany their morning song bouts by spectacular locomotor displays that may include branch shaking and branch braking. These displays typically occur at the climax of the great-call, the most conspicuous and stereotyped song phrase of the female. Here I report on a captive female white-handed gibbon slamming the sliding door of her wooden sleeping box during the climax of her great-call. This special addition to her display produced a single, loud bang which acoustically accentuated the climax of the female’s great-call, made her great-call sound unique, and possibly enhanced the call’s effect on potential receivers (presumably female conspecifics). The female’s use of a door to modify her duet contributions represents a novel behavioural variant, and one of the few cases of tool use in gibbons or small apes. Furthermore, behavioural innovations like this one may have played a role in the evolution of human music.