ABSTRACT
Hominoids differ in that they are divided at the family rather than the subfamily level. The two ape families are informally called the gibbons and the great apes. The descriptions of primate behavior are arranged under: ecology, sociality, life cycle, and cognition. Gibbons live in Asian tropical forests and use two forms of brachiation: pendular and ricochetal. Most gibbons are ripe fruit specialists. Gibbons sing complex songs, often duets, which may be associated with sex or bonding or defense against conspecifics or predators. Juvenile food begging may be for play or bonding. Great apes are large, sexually dimorphic, and largely quadrumanous. Voluntary gestural communication facilitates social groups and networks larger than those of gibbons. First pregnancy typically occurs at 10 years and a male reaches full physical and social maturity at about 13. Some researchers consider ape-human cognitive comparisons to be anthropomorphic, but others accept mental images as part of great ape cognition.
