The orangutan is an arboreal ape from the pongin subfamily. Their genome is one of the closest to the human. They have a very characteristic expression of the muzzle – the most expressive of the large monkeys. They are peaceful and calm animals whose habitat is being reduced due to human activities.
Origin of the species and description
The orangutans were the only pongins left alive. This subfamily previously included a number of other genera, now extinct, such as Sivapithecus and Gigantopithecus. The origin of orangutans is still not completely clear – there are several hypotheses in this regard.
According to one of them, orangutans descended from Sivapithecus, whose fossils found in Hindustan are close in many respects to the skeleton of orangutans. Another deduces their origin from Koratpithecus – hominoids that lived on the territory of modern Indochina. There are other versions, but none of them has yet been accepted as the main one.
The scientific description of the Kalimantan orangutan was obtained in the work of Carl Linnaeus “The Origin of Species” in 1760. Its Latin name is Pongo pygmaeus. The Sumartan orangutan (Pongo abelii) was described somewhat later – in 1827 by Rene Lesson.
It is noteworthy that for a long time they were considered subspecies of the same species. Already in the 20th century it was established that these are different species. Moreover: in 1997, it was discovered, and only in 2017, the third species was officially recognized – Pongo tapanuliensis, the Tapanul orangutan. Its representatives live on the island of Sumatra, but genetically closer not to the Sumatran orangutan, but to the Kalimantan.
An interesting fact: the DNA of orangutans changes slowly, significantly inferior to chimpanzees or humans in this. According to the results of genetic analysis, scientists suggest that they are much closer to common ancestors than any other modern hominids.
Appearance and features
The description is given for the Kalimantan orangutan – the species differ little in appearance, and therefore it is almost completely suitable for others. Those differences that exist between them will be analyzed separately.
The growth of this monkey when raised on its hind legs is up to 140-150 cm for males and 105-115 for females. Males weigh an average of 80 kg, females 40-50 kg. Thus, sexual dimorphism is expressed mainly in size. In addition, adult males are distinguished by large fangs and a thick beard, as well as growths on the cheeks.
There is no hairline on the face of the orangutan, the skin is dark. He has a wide forehead and a facial skeleton. The jaw is massive, and the teeth are strong and powerful – they are adapted for cracking hard nuts. The eyes are set very close, while the look of the animal is very meaningful and seems kind. There are no claws on the fingers – the nails resemble human ones.
The orangutan has a long and hard coat, its shade is brown-red. On the head and shoulders, it grows upwards, on all other parts of the body downwards. The animal has little hair on the palms, chest and lower body, it is very thick on the sides.
The brain of this monkey is remarkable: it is relatively small in volume – up to 500 cubic centimeters. It is far from a man with his 1200-1600, but in comparison with other monkeys, orangutans have it more developed, with many convolutions. Therefore, many scientists recognize them as the most intelligent monkeys, although there is no single point of view on this matter – other researchers give the palm to chimpanzees or gorillas.
Sumatran orangutans outwardly differ from them only in that their size is slightly smaller. Tapanul has a smaller head than Sumatran. Their hair is more curly, and even females grow beards.
An interesting fact: If among the Kalimantan sexually mature males, the majority has growths on the cheeks, and any of those who have them can mate with females, then the Sumatran situation is completely different – only rare dominant males acquire growths, each of which controls the group at once females.
Where does the orangutan live?
Habitat – swampy tropical lowlands. It is imperative that they are overgrown with dense forest – orangutans spend almost all their time on trees. If earlier they lived in a vast territory that included most of Southeast Asia, then to this day they have survived only on two islands – Kalimantan and Sumatra.
There are many more Kalimantan orangutans, they can be found in many parts of the island in areas below 1,500 meters above sea level. The subspecies pygmaeus lives in the northern part of Kalimantan, morio prefers the lands located a little to the south, and wurmbii inhabits a fairly wide area in the southwest.
Sumatran inhabit the northern part of the island. Finally, the Tapanul orangutans also live in Sumatra, but in isolation from the Sumatran ones. All of them are concentrated in one forest – Batang Toru, located in the province of South Tapanuli. Their habitat is quite small and does not exceed 1 thousand square kilometers.
Orangutans live in dense and extensive forests, because they do not like to descend to the ground. Even when there is a large distance between the trees, they prefer to jump over using long vines for this. They are afraid of water and do not settle near it – they do not even need to go to the watering place, since they get enough water from the vegetation they consume or drink it from tree hollows.
What does an orangutan eat?
The basis of the diet is plant foods :
- Fruit (plum , mango, banana, fig, rambutan, mango, durian and others);
They love to feast on honey and often specifically seek out bee hives, even despite the impending danger. They usually eat right on the trees, different from many other monkeys that go down for this. An orangutan can descend only if it has spotted something tasty on the ground – it will simply not pluck the grass.
They also consume animal food: they eat caught insects and larvae, and when bird nests are found, eggs and chicks. Sumatran orangutans sometimes even specifically prey on small primates – loris. This happens in lean years, when plant food is not enough. Cones and caterpillars play an important role in the diet of Tapanul orangutans.
Due to the low content of minerals necessary for the body in the diet, they can sometimes swallow the soil, so their shortage is compensated. Metabolism in orangutans is slow – because of this, they are often lethargic, but they can eat little. Moreover, they are able to do without food for a long time, even after two days of hunger, the orangutan will not be exhausted.
Interesting fact: The name “orangutan” comes from the cry of orang hutan, with which the locals warned each other about the danger, seeing them. It translates as “forest man”. Another version of the name “orangutan” is also common in Russian, but it is unofficial, and in Malay this word means a debtor at all.
Character and image features life
These monkeys live mostly solitary and almost always stay in the trees – this makes it difficult to observe them in the wild, as a result of which their behavior in the natural environment has long remained poorly studied. In the natural environment, they are still much less studied than chimpanzees or gorillas, but the main features of their lifestyle are known to science.
Orangutans are smart – some of them use tools to get food, and once in captivity they quickly adopt useful habits of people. They communicate with each other using an extensive set of sounds that express a variety of emotions – anger, irritation, threat, warning of danger, and others.
The structure of their body is ideally suited for life on trees, they can cling to branches with equal dexterity with both hands and long legs. Able to move long distances exclusively through trees. They feel insecure on the ground, and therefore they even prefer to sleep at a height, in the branches.
This is why they build nests. The ability to build a nest is a very important skill for every orangutan, in which they begin to practice from childhood. Juveniles do this under adult supervision, and it takes them several years to learn how to build strong nests that can support their weight.
And this is very important, because the nest is built at a high altitude, and if it poorly built, the monkey may fall and break. Therefore, while the cubs are learning to build their own nests, they sleep with their mothers. But sooner or later, there comes a moment when their weight becomes too large, and the mother refuses to let them into the nest, because it may not withstand the load – then they have to start adulthood.
They try to equip the dwelling so that it is comfortable – they bring more foliage so that it is soft to sleep, they are looking for soft branches with wide leaves to hide behind them from above. In captivity, they quickly learn to use blankets. Orangutans live up to 30 or even 40 years, in captivity they can reach 50-60 years.
Social structure and reproduction
Orangutans spend most of their time alone, the males divide the territory among themselves, and do not wander into someone else's. If this does happen, and the intruder is seen, the owner and he make noise, show fangs and intimidate each other. This is usually where everything ends – one of the males admits that he is weaker and leaves without a fight. In rare cases, they do happen.
Thus, the social structure of orangutans is very different from that characteristic of gorillas or chimpanzees – they do not keep in groups, and the main social unit is mother and child, rarely several. Males live separately, while Sumatran orangutans have up to a dozen females for one mating male.
Despite the fact that most of the time these orangutans spend separately from each other, sometimes they still gather in groups – this happens around the best fruit trees. Here they interact with each other through a set of sounds.
Sumatran orangutans are more focused on group interaction, in Kalimantan it rarely occurs. Researchers believe that this difference is due to the greater abundance of food and the presence of predators in Sumatra – being in a group makes orangutans feel more secure.
Females reach sexual maturity by 8-10 years, males five years later. Usually one cub is born, much less often 2-3. The interval between births is 6-9 years, it is very long for mammals. This is due to adaptation to the periods of greatest abundance of food that occur on the islands with the same interval – it is at this time that an explosion in the birth rate is observed.
It is also important that after birth, the mother is engaged in raising the baby for several years – the first 3-4 years she feeds him with milk, and young orangutans continue to live with her after that, sometimes up to 7-8 years.
Natural enemies of orangutans
Since orangutans almost never come down from trees, they are very difficult prey for predators. In addition, they are large and strong – because of this, there are practically no predators in Kalimantan that would hunt adults. Young orangutans or even cubs are another matter, crocodiles, pythons and other predators can be dangerous for them.
In Sumatra, even adult orangutans can be hunted by tigers. In any case, predatory animals are far from the main threat to these monkeys. As is the case with many other animals, humans are the main danger to them.
Even though they live in dense tropical forests far from civilization, its influence is still felt. Orangutans suffer from deforestation, many of them are killed by poachers or are sold alive on the black market – they are quite highly valued.
Interesting fact: Orangutans also communicate with gestures – the researchers were able to find that they use a large number of them – more than 60. With the help of gestures, they can invite each other to play or look at something. Gestures serve as a call for grooming (this is the name of the process of putting in order the coat of another monkey – removing dirt, insects and other foreign objects from it).
They also express a request to share food or a demand to leave the territory . They can also be used to warn other monkeys of imminent danger – unlike the cries, which are also used for this, with the help of gestures the warning can be made unnoticed by the predator.
Species population and status
The international status of all three orangutan species is CR (critically endangered).
The estimated population is:
- Kalimantan – 50,000 – 60,000 individuals, including approximately 30,000 wurmbii, 15,000 morio and 7,000 pygmaeus;
- Sumatran – about 7,000 primates;
- Tapanul – less than 800 individuals.
All three species are equally protected, since even the most numerous, Kalimantan, is rapidly dying out. Even 30-40 years ago, scientists believed that orangutans in the wild would disappear by now, since the dynamics of their numbers at that time testified to this.
Fortunately, this did not happen, but fundamental changes for the better also did not happen – the situation continues to be critical. Since the middle of the last century, when systematic calculations began, the population of orangutans has decreased by four times, and this despite the fact that even then it was significantly undermined.
First of all, the animals are harmed by the reduction of the territory suitable for their habitat, due to intensive logging and the appearance of oil palm plantations instead of forests. Another factor is poaching. In the last decades alone, tens of thousands of orangutans have been killed by humans.
The population of Tapanul orangutans is so small that it is threatened with degeneration due to inevitable inbreeding. Representatives of the species show signs that this process has already begun.
Despite the status endangered species, the measures taken to protect the orangutan are not effective enough. Most importantly, their habitat continues to be destroyed, and the authorities of the countries where they still exist (Indonesia and Malaysia) are taking little action to change the situation.
The monkeys themselves are protected by law, but they continue to be hunted, and they are still being sold on the black market. Except that over the past two decades, it has been possible to reduce the scale of poaching. This is already an important achievement, without which orangutans would be even closer to extinction, but the fight against poachers, a significant part of which are local residents, is still not systematic enough.
On the positive side, it is worth noting the creation of rehabilitation centers for orangutans in both Kalimantan and Sumatra. They try to minimize the consequences of poaching – orphaned cubs are collected and raised before being released into the forest.
At these centers, monkeys are taught everything necessary for survival in the wild. Several thousand individuals have passed through such centers – the contribution of their creation to the fact that the orangutan population is still preserved is very large.
Interesting fact: The ability of orangutans to make extraordinary decisions is more pronounced than other monkeys – for example, the process of building a hammock by a female Nemo living in captivity was caught on video. And this is far from the only case in which orangutans use knots.
The orangutan is a very interesting and still poorly understood species of monkey. Their ingenuity and ability to learn is amazing, they are friendly to humans, but in return they often receive a completely different attitude. It is because of people that they were on the verge of extinction, and therefore the primary task of man is to ensure their survival.