He becomes less vulnerable to attack. The infant is an agonistic buffer. Allomothers may be practicing parenting skills, reciprocating or helping mothers, or may attempt to kidnap and harrn the infant. A behavior that costs the doer and benefits others. Anthropology 60 Teaching Assistants are the only true altruists known to exist.
Gibbons are highly arboreal.
Walking upright on two feet. Humans are the only habitually bipedal primates. Gibbons are brachiators extraordinaire. The number of individuals an environment can support without degradation. One of two major taxonomic subdivisions within Old World monkeys.