head of another with hands, often in grooming. Also in bonobos. 2. See video. pull leaf-pile Walk backwards quadrupedally while raking dry leaves with hands. Locomotor-object play. Cf. push leaf-pile. See video. pull object from opposing sides Tug of war. Two individuals simultaneously pull object competitively from opposite sides. Component of social play. Also in bonobos. Cf. pull each other. See videos. See also video play socially with object. pull out Pull forcefully with hands, often countered by pushing feet against ground. Chimpanzee tries to uproot stalk of banana, elephant grass, or African ginger from earth. Also, standing quadrupedal and pulling up heavy rotten wood with arms. Also in bonobos. See video. pull rock to roll Adult or adolescent male pulls rock along substrate with hand while walking