Essay: Orangutans – 'The man of the forest'

‘The man of the forest’ is often what people would call orangutans in Malay language. They are the only great apes that find in Asia. Orangutan lives in Indonesia and Malaysia. They often habitat on the island of Borneo and Sumatra in Indonesia, and these are the only places they are naturally found. Orangutan have a large body, cover with long, reddish-brown hair and grey-black skin. Long and strong arms, gripping hands, permanently curved, long finger and toes that makes them agile on the trees. Flexible hips and shoulders, with no tail, and they have large brain among the animals. Although these two species are from the same Pongidae family, their appearance features have a slightly difference. Sumatran orangutan (Pongo abelii) has lighter color hair, a longer beard, and slightly smaller size than Borneo orangutan (Pongo pygmaeus). In the primates of true apes, including gorilla, chimpanzee, the size of orangutan is second in size only to the gorilla. How to distinguish orangutans from monkeys are by their large size, with no tail, their large brains, and they can swing with their long arms. Female and male orangutan basically has similar features, but they look different on their size. Female orangutan weight about 80 lbs, and male orangutan weight about 160 lbs. Males are twice the size than females.
Orangutan mostly lives on trees, and they are the only great apes that are arboreal. Their curved finger and toes is relatively adapted for arboreal climbing and grip material. The strong arms, grasping hands and feet allow them to swing between tree branches. Orangutan would build their homes and find foods on trees. Orangutan barely walks on the ground in the wild, and they would come down to the ground when necessary. They could not walk with their knuckles like chimpanzees. Orangutan walks on their fist. They use the sides of clenched hands and feet, which make them very uncomfortable. Orangutan is very well adapted for arboreal lifestyle on trees, except the orangutan that lives in zoo. Orangutans are vegetarians, they mainly eat fruits. They also eat twigs, buds, insects, and vines.
Orangutan in the wild is facing many threats, including destroy the agriculture, mining, logging, and especially elimination of the food sources. Because they mainly eat fruits, they are frugivores. Their favorite fruit called durian, it covers with sharp spines and smell very bad. They use their powerful jaws to open durian. When the fruit source is shortage, wild orangutan will also eat young leaves, honey, flowers, bark, and nuts. Sometimes they also eat bird eggs, and insects. They drink the water on the leaves from rains. When water is difficult to get, they chew the leaves to make a sponge to absorb water in tree holes. Orangutan in the zoo would eat fruits such as apples, oranges, and bananas, and they also eat vegetables like carrots and lettuce. Usually wild orangutan acquires foods on the trees to avoid coming down to the ground because to the limit of their movement, their curved toes and for protection. Orangutan is the only great ape mainly travel through trees, they use a method call ‘Fist Walking’. As the name implies, orangutan curls the thumbs around the fist and walk on their fists. Because of the body structure of orangutan of long arms and grasping hands and feet, it benefits orangutan flexible to climb and agile between trees, but it makes them walk slow and awkward on the ground. This may explain the reason most of the time orangutans stay on trees and occasionally come down to the ground. Orangutans have their home and food availability is there, and they are safer up there too.
Scientists had thought that the use of tools is a feature unique to humans, but more and more studies discover that animals also able to skillfully use some tools to obtain food. Such as orangutans use branch like a stick tool to extract seeds off the fruits’ hard shelled. Orangutans have seemed to use leaf like an umbrella to cover them from getting wet, and use sticks for stretching. They have observed to use pole to catch fish from locals’ fishing net after observe humans using spear fishing. In the study of Russon, he reports a new tool technique orangutan on leaf-carrying. Orangutan collects the nest materials and uses it to build the nest (189-202). Not only orangutan in the wild has observed to make tools and use them in their lives, orangutan in captivity has been found highly intelligent. In the study of the tool use of captive orangutan, Nakamichi observed when orangutan unable to acquire foods from the ground, then they would strip leaves and twigs from a branch, and use the tool to insert the hole to get foods (87-93). The orangutan in captivity have also seems to use vines as lasso to catch the plants from distance and bring it to themselves. When orangutan does not success to obtain foods from their tools, they usually modified the tool, such as to change the amount of leaves on the branch to makes it easier to get more food from the holes. We do not often see young orangutan uses any tools, but many adult orangutans have the skills of tool-making and using. From these examples, it implies that orangutan may have the ability to pass their living habits and social skills generation to generation. Since orangutan is the closest primate to human, orangutan’s tool manufacturing skills maybe particularly relevant to the human evolution of tool use. It also reveals that orangutans have the cognitive abilities, from their manufacture tools to tool use skills.
Orangutans are the closest great ape to humans, and they share more than 96% DNA in common. They are extremely intelligent and many of their social organization are similar to humans. Orangutan is monogamy. Male orangutan would only mate with only one female orangutan. Adult male orangutans unlike other great ape, instead of living in a group, they are solitary. The only time males will come for the females is when mating. After male orangutans mated with female orangutans, they could leave the females alone to raise the infant. While the females rearing the infants, they will not mate with other males. Females will rear their dependent offspring for seven years before let them become independent. Therefore, a female orangutan can only give birth three times in their life. In the journal of Current Anthroplogy, van Schaik tells how the limitation food sources can influences the social structure of orangutans (878-882). Adult female orangutans often live with the young to stay away from the males. This related to the size and diet of males. Since male orangutans are twice the size as the females, they need high an amount of fruits. To avoid food competition and limited food available, male orangutans would not be in the social group with the females and young.
In the end, we learned that orangutan is the only great ape would find wild in Asia, there are two species of orangutan, Bornean and Sumatran. Both have shaggy reddish fur. They are mainly arboreal, their long arms and grasping hands have advantage to climb through trees. Orangutan mainly eats fruits, and sometime they also eat fresh leaves, and insects. Orangutan has high intelligence. Just like humans, orangutan creates and use tools, their social learning implicate the evolution of humans. Orangutan is the closest relatives to humans, sharing 97% DNA. Some scientists also suggest that they share a common ancestor with humans. Male orangutan is the only solitary high primates; they do not live with female orangutan and young because of their large size and great amount of diet.
Orangutan is known as extremely intelligent and unique in many ways, however, they are critically endangered and the population in the wild is decreasing drastically. The natural disasters, includes global warming causes the climate changing. And their habitat destruction caused by destroying the agriculture, mining, and logging. Especially the palm oil plantations, this will take away the orangutan home and lives (Zajac 19). Logging reduces the habitats orangutan can stay; it will force orangutan to move more. It also decreases the amounts of orangutan food resources. It will results in rapidly decline the population of orangutan. This is pushing this unique species to extinction. When the habitat of orangutan is being damage, it may bring negative effect to the behavior of orangutan. Environment plays an important role in evolution behavior of orangutans, including other primates. Primates learns how to response to the natural selection from generation to generation, they also able to react to the changing environment. Improving social behavior and tool-using proves the evolutionary process has made.