Gone Orang(e)?!

Orangutans (orang-hutans) are native to Indonesia and Malaysia, though they are currently found in the rainforests of Sumatra and Borneo. Orangutans are very intelligent animals. They are the only surviving species in the genus Pongo. ‘Orang-hutan’ in Malay refers to ‘person of the forest’. It is believed that orang-utans have a very high level of intelligence. According to recent research by James Lee, a psychologist at Harvard,” Orangutans are the world’s most intelligent animal other than man, with higher learning and problem solving ability than chimpanzees, which were previously considered to have greater abilities.”

An orangutan’s lifespan is about 35-40 years in the wild, and sometimes 50 years in captivity. Like human beings, orangutans have very extended ‘childhoods’. They reach puberty at age 8. Young males may stay close to their mother for one or two more years. Females stay until they are in their teens, so as to pick up mothering skills as they watch their mother nurse a sibling.

Orangutans start the process of learning at a very young age. Their behaviour reflects very much in the behaviour of human children; children will continue to do something only after positive approval form the parents. They learn through observation and imitation of their mother. Orangutan offspring are isolated from relatives and their only source of information is from the mother, the main caretaker. This is why the death of the mother can be devastating to the young one. 

Through observation, imitation and practice, the young ones learn basic survival strategies. One primary example is the requisition of skills that the mother exhibits. Orangutans have been observed to sample the mother’s food to learn acceptable foods as well as follow her hand and learn the feel of the source in order to be able to locate food upon separation from the mother .They learn then what to eat and how to eat it. But at this stage, learning tool-based skills is challenging.

There is a great deal of communication between the young ones and the mother when it comes to learning from her. Much of the communication happens through eye contact and gestures. For example, when a young one has to beg for food, it constantly shifts its gaze back and forth from the mother to the food item. Similarly, the mother gestures to the young one to climb on to her body by extending a limb, usually a leg to touch the infant. They also communicate in other ways such as, vocalizations, body posture, facial expression, touching as well as movement of the eye and the eyelid. This exchange helps the young to understand how to communicate with others of its kind. And in turn, through this learning of how to communicate, it builds a stage for social learning to happen. 

Orangutans also learn through imitation. They observe the mother’s movements and thus this learning enables them through imitation to use movements. The learning allows them to be able to collect food for themselves once they are separated from the mother. They then begin their journey as young adults. They look for new company and a place to settle. In the process, they end up learning new techniques of survival. They learn new skills through interaction with other orangutans. 

 However, orangutans are semi-solitary animals due to there being a scarcity of food in the rainforests. However when there is an abundance of food, they will use the opportunity for social interaction. Adult males will give up their solitary status when they find a female who is receptive to mating. They will then stay with the female to ensure a successful mating, after which they will resume their solitary existence. Adults spend no more than ten percent of their time with other adults. When male contact happens, most situations turn hostile.

Orangutans learn throughout their lifetime. These animals are said to have the longest childhood dependence on the mother than any other animal in the world. Their learning happens primarily from the mother and then through contact with each other. They are taught which foods to eat and which to not eat, and where to get them. By the time they move away, they have a precise map of the forest and also detailed information on the fruiting cycles of trees. In a way, the mother makes sure they prepare and ensure that their young are suited to live life alone. Only when young orangutans move away do they start to explore their surroundings and learn by themselves. Their learning process is slow and their period of development is long so as to evolve the capability to absorb enormous amounts of local knowledge which they can then put to use. 

Orangutans have displayed signs of high intelligence in activities involving tool-based skills. These skills as well as learned behaviour suggest to some extent some form of orang-utan culture and social interaction. Culture plays a big role in the survival of an orang-utan. Its behaviour is not genetically determined, as was thought, but rather learnt through watching others. Tool uses as well as social signalling are learnt through observational learning. The theory is that if one group of orangutans display behaviour it will most likely be different from another group’s behaviour. This demonstrates that behaviour and thus learning is highly culture specific.  

Some tool use and social signalling skills – 

Ø      Handling Thorny Fruits: Orang-utans have devised a method to handle thorny fruits. They use leaf pads when they pluck the fruit. They use the leaves as napkins or gloves to protect their hands from the spines on the fruits.

Ø      Nest building: Since orang-utans live largely solitary lives, they sleep alone in nests that they build. They are arboreal animals and spend most of their time in the tree tops. These nests shelter them from the rain and provide a comfortable place to sleep. Young orang-utans start building nests at the age of just fourteen months and at the age of five years they can construct good solid nests.

Ø      They use sticks to dig out seeds from fruit. They use it to poke into tree holes to search for insects and to scratch themselves.

Ø      They use leafy branches to swat insects or gather water.

Ø      They ride on falling dead trees to grab vegetation before the tree hits the ground.

Ø      They build sun and rain covers for nests.

Ø      They call to one another using a technique wherein they press their hands or leaves against their lips to make a loud sound; called a kiss-squeak.

 Ø      When rain water is difficult to get, they chew leaves to make a sponge to soap up water in tree cavities.

Ø      When it rains very hard, they make an umbrella out of big leaves.

A study was done by Carel Van Schaik and researchers on why orangutan behaviour was culture specific and not universal. He proved that orangutan behaviour was a result of culture innovation and not ecological adaptation. He first found that sites that are geographically more closer have similarity in behaviour. This demonstrates the fact that orangutans pass on their behavior as they roam. Secondly, he noticed that the number of cultural behaviors is highest in regions where there is more social interaction. This clearly suggests that learning not only happens through observation and signaling, but also that cultural learning does take place. Lastly they studied that apes in similar habitats do not share more behaviour than apes in different habitats. This goes to show that these animals do not develop the same behaviors when faced with the same challenge.

One important example came from another finding of Carel Van Schaik. He noticed that orangutans on one side of a Sumatran river used sticks to remove seeds from a prickly fruit, while orangutans on the other side of the river did not. The habitats on both sides of the river were the same, but their behaviour was different. This shows that behaviour results from innovation.

 Another example to note is that one band of orangutans in Sumatra were seen to hold a stick in their hand while trying to pry the seeds from a thorny fruit, while another group used leaf pads as gloves to do the same. Groups of orangutans have distinct methods of feeding, nesting and communicating. In turn, learning is very specific to the group and an orangutan will learn and pass on survival strategies that they learn from the group that they belong to.

Orangutans are well adapted to the rainforest environment. They obtain large amounts of food right from the scavenging on the forest floor to the top of canopies. They know exactly where to find edible roots, how to pick fruits from different heights, which nuts, leaves and barks to feed on. Their protein comes from eating reptiles, ants and eggs. They successfully raise their offspring.So well have they adapted to their surrounding environment that they are now considered to be indicator species. Indicator species are species that act as the barometer for the well being of other species in the same environment and generally for the health of the entire rainforest. Sadly, from the nineteenth century onwards, large scale logging of forests and killing sprees of this species have resulted in orangutans being added to the long list of endangered species. Today, their behaviour can be thought of as adaptations to their shrinking habitat and other environmental pressures that endanger their lives.