Orangutans are the only remaining Asian genus of the present day living great ape. Orangutans are the largest living arboreal animals. They have longer arms as compared to other great apes. They are among the most intelligent primates who use a vast variety of tools and also make sophisticated nests every night from leaves and foliage while sleeping. Most part of their lives in spent in food searching and they are not aggressive animals. The body hairs are typically reddish-brown very different from the black hairs as found in apes.
Orangutans are native to Indonesia and Malaysia but at present they are found only in the rainforests on the islands of Borneo and Sumatra. Their fossils have been discovered from Java, the Thai-Malay Peninsula, Vietnam and Mainland China. Only two species are alive today and both share the category of endangered. These two extant species are Bornean Orangutan and the critically endangered Sumatran Orangutan. These animals have derived their name from Malay word which means man of the forest.
Adults attain a height of about 4-7 ft while standing. The body weight may vary from 33-82 kg. Males may attain body weight up to 110 kg or more. Their hands resemble with that of humans consisting of four long fingers and one opposable thumb. They also have four long toes and one opposable big toe. They are able to grasp things both with the help of their hands as well as feet.
Orangutans have bulky body, a thick neck, very long, strong arms, short, bowed legs, and no tail. Sumatran have light coloured coat. They have large head with prominent mouth area. Adult males have large cheek flaps that demarcate their dominance among other members of the group. The females attain maturity at the age of 12 years. They have an average lifespan of 35 years but in captivity they can live up to 60 years. Both the sexes have throat pouches near the vocal chords which are used to generate calls in the forests. They are arboreal and spend most of their time on the trees. They make sleeping nest in the night. Generally they are solitary and male and female come together only for the purpose of mating. The young ones remain with the mother for about 7-8 years. There is a well developed sexual dimorphism. The females are 4 ft in length and weigh about 45 kg while males are 5 ft and weigh 118 kg.
Fruits make their 65-90% diet. Fruits carrying sugary and fatty pulp are most favoured. Ficus fruits are mostly prefer as they are easy to harvest and digest. They are opportunistic foragers and their food composition varies from month to month. They are known to rape human females. Actress Julia Roberts had an orangutan try to have sex with her, and was saved by a film crew. The Sumatran species are considered to be critically endangered while Bornean species is endangered according to the list of IUCN. They have 48 diploid chromosomes and the whole genome sequence was identified in January 2011.