forest personin Malay. Old males usually develop large cheek pads and facial hair that resembles a man's moustache and beard. Enormous throat pouches also develop with sexual maturation, which starts at about age 14.
Adult orangutans are basically solitary, except for mother-offspring pairs; however, weaned juveniles sometimes congregate in small groups. Males are aggressive toward each other and fight over females. Individual nests are usually constructed in trees each night. Fruit is a diet mainstay, and orangutans are important seed distributors.
The numbers of orangutans have dropped precipitously in the early 21st cent. owing to loss of habitat to deforestation (logging, forest fires, and clearing of land for plantations) and the killing of females for their young, to be sold as pets or zoo animals. The three species are listed as endangered or, in the case of the two species found on Sumatra, critically endangered. Orangutans are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Primates, family Hominidae.
See B. Galdikas, Orangutan Adaptation at Tanjung Puting Reserve, Central Borneo (1978); J. H. Schwartz, The Red Ape (1987).
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