irregularly shakes long dry grass, both vertically and horizontally, as threat to human observer. Category 9. See video. shake object up and down Stand and shake up and down bush or dead tree by hand, in threat or social play. See video. shake off While seated or standing, forcefully shake off play partner from body contact. Throw down opponent by hand in wrestling as in sumo. See video. shake other Old female, Calliope, grasped knee of Fanana and shook it back and force in greeting. Adult female, Xtina, grasped shoulder of another adult female, Ruby, and shook it back and forth when agitated. Adolescent male, Cadmus, grasped and shook juvenile males heel as play. Idiosyncratic?. See video. shake penis Adult male grasps and shakes vertically anothers penis, while