Orangutans derive their name from the Malaysian and Indonesian words orang, meaning person and hutan, meaning forest. The name orangutan means “man of the forest” in the Malay language. There are two species of orangutan, the Bornean orangutan and the Sumatran orangutan. Both species are highly adapted to an arboreal way of life and rely on forests to provide them with food and shelter. As a result, habitat loss has had a dramatic impact on orangutan populations.
Physical Description of the Orangutan
Orangutans are large, tree-dwelling mammals with large jaws and long, shaggy orange or auburn fur. In a standing position, an adult male orangutan can reach up to 5 feet in height. Males can weigh as little as 100 pounds or as much as 250 pounds. Female orangutans are smaller, reaching a maximum height of 3.5 feet. The average weight of a female orangutan is between 60 and 110 pounds. The orangutan has relatively short legs in comparison to its long arms which almost reach the ground when the animal is standing in an upright position. A fully-grown orangutan’s arm span can be as wide as 7 feet. Long, strong arms and grasping hand and feet help the orangutan to move around its habitat effectively.
There are some physical differences between orangutans in Borneo and orangutans in Sumatra. Sumatran orangutans (Pongo abelii) have long hair on their faces while Bornean orangutans (Pongo pygmaeus) do not. While the male Bornean orangutan has a large throat sack, the Sumatran male either has a smaller version or lacks a throat sack entirely. Orangutans in Borneo also have larger cheeks than those in Sumatra.
Orangutan Habitat and Range
Orangutans can only be found living in their native tropical and sub-tropical rainforest habitats on the islands of Sumatra and Borneo. According to Honolulu Zoo, orangutans once lived throughout a large portion of Southeast Asia. The extent of the animal’s range has decreased considerably. In their forest habitats, orangutans usually live in lowland areas, floodplains and the lower or middle layers of the rainforest. Orangutans spend the majority of their time in trees, whether awake or asleep in leafy nests.
Orangutan Diet and Feeding Habits
Orangutans are diurnal animals that forage for food during the daylight and sleep at night. The largest part of the orangutan’s omnivorous diet is comprised of fruit such as lychees, mangoes and figs. Other plant matter such as bark and leaves also form a part of the orangutan’s diet. More rarely, the orangutan may also eat insects and bird eggs. Flat teeth and powerful jaws help the orangutan to tear at vegetation, open fruit and break down food.
Female orangutans begin to reproduce when they reach sexual maturity at the age of around 10 years old. Males mature later and begin to reproduce at around 12 years of age. Male orangutans prefer a solitary existence and rarely come together with other orangutans other than when they are mating. Female orangutans usually give birth to one baby after a gestation period of between 235 and 270 days. Occasionally, an orangutan will give birth to two young from a single pregnancy. Orangutans have a very slow rate of reproduction, often giving birth to one baby around every eight years. Although orangutans can live for more than 50 years, females are only fertile for around 20 of these. Young orangutans usually become independent from their mothers by around 7 years of age.
Why Are Orangutans Endangered Animals?
According to the World Wildlife Fund, there are approximately 41,000 Bornean orangutans and 7,500 Sumatran orangutans in existence in 2011. This is compared with a total population of approximately 230,000 or more around 100 years ago. Bornean orangutans are endangered and Sumatran orangutans are critically endangered. Orangutan populations have declined as the result of habitat loss through deforestation, capture for the illegal pet trade hunting, and cropping palm oil.