Orangutans Essay

1026 Words Oct 24th, 1999 5 Pages

Tim Sanderson
Anth 111

In Malay orang means "person" and utan is defined as "forest'. Thus
Orangutan literally means "Person of the Forest". Orangutans are found in the tropical forests of Sumatra and Borneo. They are the most arboreal of the great apes and move amongst the safety of the trees from one feeding site to the next.
They are so well adapted to arboreal life that they cannot place their feet on the ground, instead they walk on the outside of their curved foot. There is a scattered population of orangutan in Indonesian Borneo,
Malaysia Borneo and northern Sumatra. The different habitats have isolated the orangutan reproductively and geographically from one another creating a "degree of difference" or two
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The Gestation period lasts slightly less than nine months. Offspring pass through three stages, infancy (0-4), juvenile (4-7), and adolescents (7-10). Mother young relationship lasts for a long time, the young usually stay with their mother until they are mature.
Female Orangutans are not sexually mature or fully grown until the age of twelve and will not have their first offspring until they are at least fourteen. Males become sexually mature and fully grown at the age of fifteen. The cheek flanges of the male easily recognize the differences between adults and semi-adults. The flanges in the Boreal male curve out ward from the face and develop around the age of eight and are not completely grown until the age of fifteen. Sumatra flange development begins at the age of ten and is not complete until the early twenties. The flange in the Sumatra orangutan lie flat against the face and give a wide facial appearance especially in the mid facial region. The life expectancy of orangutans in the wild is not known, but captive orangutans have been known to live up to fifty years. Orangutans are sexually dimorphic. Males are approximately twice the size of females and weigh about 220 lbs. and reach a height of five feet. It is believed that the males larger size may be an adaptation for mating because there is strong competition among males for females. The pendulous laryngeal sac, when inflated, increases the tone of the

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