Belonging to the family of Great Apes, orangutans are some of the largest existing primates and the only members of the great ape family found outside of Africa.
These apes are native to Indonesia and Malaysia and are now only found in some parts of Borneo and Sumatra.
Of all the great apes, orangutans are the most arboreal, preferring to spend most of their time in trees.
They are also among the most intelligent primates, which has led to the start of numerous research projects on their intelligence.
We share 96.4% of our DNA with these forest-dwelling apes, making orangutans one of our closest living cousins.
Initially, all orangutans were classified as one species.
By 1996, two separate species—the Bornean orangutan, which has three subspecies, and the Sumatran orangutan—were established.
However, by 2017, a third species was added to the list—the Tapanuli orangutan.
The three species are actually quite similar in terms of behavior and appearance.
Human activity has a negative impact on the three species’ native habitats, and the IUCN has designated them as critically endangered.
This article will shed more light on these species and their unique features.
Orangutan Species
Originally, it was thought that the Bornean and Sumatran orangutans belonged to the same species.
However, extensive genetic research revealed otherwise. There is also a taxonomy debate currently going on among experts.
According to some researchers, the Southwest Bornean is more closely related to the Sumatran Bornean orangutan than the Bornean orangutan.
However, for the time being, the three subspecies are still classified under the title of the Bornean orangutan.
This portion of the article will shed more light on the different orangutan species and what makes them different from each other.
3. Bornean Orangutan
Otherwise known as Pongo pygmaeus, the Bornean orangutan is an orangutan species endemic to Bornea; it is also a part of the one genus of great apes native to Asia.
This species is further divided into three subspecies. The first is the Northwest Bornean orangutan, the most threatened subspecies.
This subspecies is the most adversely impacted of the three due primarily to the ongoing disturbance of its habitat caused by human activity, especially logging, and hunting.
The second subspecies is the Northeast Bornean orangutan, the smallest of all the subspecies in size.
The last subspecies is the Central Bornean orangutan, with the highest number of orangutans.
Bornean orangutans are the largest arboreal primates and the third-largest living ape species.
Generally, male Bornean orangutans weigh more than their female counterparts.
The average male weighs between 110 and 220 pounds and can grow as tall as almost six feet.
On the other hand, females weigh between 66 and 110 pounds and can reach heights of nearly four feet.
The body shape of the Bornean orangutan is distinctive; it has long arms, a reddish coarse coat, and gray skin.
Unlike most animals, it has no coat to protect its face, although Bornean orangutans do grow some facial hair, including a beard and mustache.
The Bornean orangutan inhabits wet tropical and subtropical broadleaf forests in both lowland and mountainous regions of Borneo.
Although living in trees, Bornean orangutans move around on the ground more than Sumatran orangutans.
This might be because orangutans in Borneo are not in danger from any sizable terrestrial predators.
Also omnivorous, this species consumes many foods, including flowers, seeds, insects, and bird eggs.
Because of their extremely slow metabolisms compared to their enormous body sizes, orangutans kept in captivity run the danger of getting severely overweight.
2. Sumatran Orangutan
The Sumatran orangutan (Pongo abelii) is more uncommon than the Bornean orangutan, critically endangered, and only found in the north of the Indonesian island of Sumatra.
The Sumatran orangutan’s historical range encompassed the whole island of Sumatra and extended farther south into Java.
The fact that numerous of these apes cluster on trees to eat suggests that Sumatran orangutans have closer social bonds than their Bornean kin.
The province of Aceh at the northernmost tip of Sumatra is home to the majority of the current population.
Like Bornean orangutans, the Sumatran species has a red coat covering their skin, but the shade of their coat is a little paler.
They also have facial hair, but instead of a mustache, they have long beards.
Sumatran orangutans are leaner, with longer faces and body hair than their Bornean counterparts.
When compared in size, the Sumatran orangutan is smaller than the Bornean.
The average male Sumatran orangutan weighs around 200 pounds and reaches over five feet.
On the other hand, female Sumatrans average a weight of 99 pounds and a height of three feet.
The Sumatran orangutan tends to be more fruit – and particularly insect-focused than the Bornean orangutan.
Sumatran orangutans enjoy eating fruits with large seeds and are surrounded by fleshy substances, such as durians, lychees, jackfruit, breadfruit, and fig fruits.
These apes also consume insects, particularly ants and other small vertebrates.
Living in the trees of tropical rainforests, the Sumatran orangutan is almost entirely arboreal.
Adult males rarely go on land, while females never do.
1. Tapanuli Orangutan
The Tapanuli orangutan (Pongo tapanuliensis) is a type of orangutan found only in South Tapanuli on the Indonesian island of Sumatra.
At first, it was categorized as part of the same species as the Sumatran orangutan, but it was declared a distinct species in 2017.
It is also more endangered than the other two orangutan species, with fewer than 800 Tapanuli orangutans left in the wild.
A more recent investigation has revealed that the former range of the Tapanuli orangutans was probably much larger than it is now.
Another study demonstrated that the current location of the residual population was most likely not a part of its original habitat.
In terms of body type and fur color, Tapanuli orangutans are more similar to Sumatran orangutans than Bornean orangutans.
However, there are still some noticeable differences. They have smaller heads with wider and flatter faces than the Sumatran species.
The flanges, or big flat cheek pads on male Tapanuli orangutans, are covered with downy hair and feature a pronounced mustache.
Like the other species, the male Tapanuli orangutan is larger than the female.
The average male is 54 inches tall and weighs between 150 and 200 pounds, whereas the average female is 43 inches tall and weighs between 88 and 110 pounds.
Tapanuli orangutans live in tropical and subtropical moist forests located south of Lake Toba in Sumatra.
Orangutans from the Tapanuli subspecies also live in the mountains, between 300 and 1,300 meters above sea level.
The entire Tapanuli orangutan population is contained within a tiny, isolated area of the hilly forests immediately south of Lake Toba, which has a range of about 1,000 square kilometers.
Their natural habitat is getting smaller and more dispersed due to continuous deforestation in the area to create room for logging, oil plantations, and expanding human populations.
Being omnivorous creatures, Tapanuli orangutans hunt and eat plants and other small animals, particularly insects, and small reptiles.
They also eat a lot of fruit.
Sources:
- https://www.sumatranorangutan.org/content/uploads/2017/11/Pongo_tapanuliensis_A4_English.pdf
- https://en.wikipedia.org/wiki/Sumatran_orangutan
- https://en.wikipedia.org/wiki/Bornean_orangutan
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