by grinning adult male. In play, usually done by youngster with play face. Also, used to grasp fruit in tree, or to climb tree. Infant does without anything overhead when requesting mother to allow access to nipple or to seek rescue. Signal for help probably originated from intention movement to seek dorsal ride on mother. See video. See also video approach and withdraw. raise arm quickly Goodall Arm threat: The arm is raised in a quick jerky movement and the fingers flexed slightly. This is usually accompanied by head tipping and cough threat or waa bark. Plooijs arm raise. Cf. shake arm. Adolescent male, Cadmus, raises arm quickly while standing bipedally for courtship as well as intimidation. Also in bonobos of Wamba. See video. raise arm slowly Extend