The Sumatran orangutan, the scientific name Pongo abelii is likely one of the three species of orangutans. Found solely within the north of the Indonesian island of Sumatra, it’s rarer than the Bornean orangutan however more widespread than the not too long ago recognized Tapanuli orangutan, additionally present in Sumatra.
In this article, I am going to talk about Sumatran Orangutan habitat, lifespan, society, population, facts, diet, conservation status, predators, endangered, weight, etc.
Sumatran Orangutan profile
Its widespread name is predicated on two separate native phrases, “orang” (“people” or “person”) and “hutan” (“forest”), derived from the official language of Malaysia, Malay, and interprets as ‘individual of the forest’.
Historically, the Sumatran orangutan was distributed over all the island of Sumatra and additional south into Java. The species’ range is now restricted to the north of the island with a majority within the provinces of North Sumatra and Aceh.
Of the 9 present populations of Sumatran orangutans, solely seven have prospects of long-term viability, every with an estimated 250 or more people. Only three populations include more than 1,000 orangutans.
Orangutans that have been confiscated from unlawful commerce or as pets are being reintroduced to Bukit Tigapuluh National Park. They number around 70 and are reproducing.
Sumatran Orangutan Geographic Distribution and Habitat
Orangutans are the great apes present in Asia, particularly on the islands of Sumatra and Borneo. Fossils present in Java, China, and Vietnam point out that they as soon as roamed bigger territories than they do as we speak.
Originally regarded as one species, two distinct species have been acknowledged in 1996: Pongo abelii in Sumatra and Pongo pygmaeus in Borneo. A 3rd species, the Tapanuli orangutan, Pongo tapanuliensis, was found in November 2017, additionally in Sumatra.
Sumatran orangutans reside in rainforests, swampy forests, and mountain forests, at altitudes decrease than 5,000 feet (1,500 m). Most of the present inhabitants are discovered within the Aceh Province on the northernmost tip of Sumatra.
This space of contiguous rain forest, protecting 16,000 sq. miles (26,000 km2), is named the Leuser Ecosystem and is the final stronghold for the Critically Endangered Sumatran orangutan.
There are some patches of forest with people south of the Leuser Ecosystem, however solely the populations of west Batang Toru and Pakpak Barat are thought of viable.
Sumatran Orangutan Description, Behavior and ecology
Male Sumatran orangutans develop to about 1.7 m (5.6 ft) tall and 90 kg (200 lb). Female species are smaller, averaging 90 cm (3.zero ft) and 45 kg (99 lb).
Compared to the Bornean species, Sumatran orangutans are much thinner and have longer faces; their hair is longer with a paler red color.
Compared with the Bornean orangutan, the Sumatran orangutan tends to be more frugivorous and particularly insectivorous. Preferred fruits embrace figs and jackfruits.
It may even eat bird eggs and small vertebrates. Sumatran orangutans spend far much less time feeding on the interior bark of bushes.
Wild Sumatran orangutans within the Suaq Balimbing swamp have been noticed utilizing instruments. An orangutan will break off a tree branch that’s a couple of foot-long, snap off the twigs, and fray one finish with its tooth.
The orangutan will use the keep on with dig in tree holes for termites. They may even use the keep on with poke a bee’s nest wall, transfer it around and catch the honey.
In addition, orangutans use instruments to eat fruit. When the fruit of the Neesia tree ripens, its arduous, ridged husk softens till it falls open.
Inside are seeds that the orangutans take pleasure in consuming, however they’re surrounded by fiberglass-like hairs which might be painful if eaten.
Tools are created in another way for various makes use of. Sticks are sometimes made longer or shorter relying on whether or not they are going to be used for bugs or fruits. If a selected tool proves helpful, the orangutan will usually reserve it.
Over time, they may accumulate whole “toolboxes”. A Neesia-eating orangutan will choose a five-inch stick, strip off its bark, after which fastidiously accumulate the hairs with it.
The Sumatran orangutan can also be more arboreal than its Bornean cousin; this may very well be due to the presence of enormous predators, just like the Sumatran tiger. It strikes via the bushes by quadrumanous locomotion and semibrachiation.
Size, Weight, and Lifespan
Male Sumatran orangutans are bigger than females. They are on common 54 inches tall (137 cm) and weigh between 155 and 200 lbs (70 to 90 kg). Females are about 43 inches tall (110 cm) and weigh between 90 and 110 lbs (40 to 50 kg).
In captivity, they are often a lot bigger and a few people in zoos are double the load they might be within the wild at 300 to 400 lbs (136 10 180 kg).
Sumatran orangutans can reside as much as 40 years within the wild and 50 in captivity.
Sumatran Orangutan Appearance
Sumatran orangutans have long orange hair. Their faces are considerably elongated and each woman and men have a beard. Males have a mustache and skinny hair covers their cheek pouches.
They have very long arms spanning 7 feet (2 m), in addition to long palms and feet. Extremely sturdy, they will carry 500 kilos (240 kg) effortlessly—which is helpful once they wish to tear off crowns of grown palm bushes to retrieve the hearts for a meal.
Their finger bones are bent inwardly and padded by fleshy cushions that enhance their grip and permit them to carry up their body weight.
Fingernails are black and each foot and palms have ridges on the within which might be distinctive to every particular person.
Feet seem like palms with a giant toe that acts like a thumb. Both palms and feet are completely tailored for shifting within the bushes.
The Sumatran orangutan’s mode of locomotion known as “quadrumanous scrambling.” Because they’re so massive, they can not swing from branch to branch.
Instead, they use each foot and palms to carry onto branches and climb to treetops. From there, they throw their weight in a selected course, forcing the branch to bend till they will seize one other branch and transfer on.
The brow of the Sumatran orangutan is pretty massive and bulges a bit. The nostril is flat with two massive nostrils, and the jaws and mouth protrude outward.
They have 32 teeth, like people, however, massive canines and central incisors are longer and have a heavier enamel floor.
A thick layer of enamel is required for gouging on bark and different tough meals gadgets. Ears are pretty small in comparison with the size of the pinnacle. Eyes are brown and guarded by eyelids and eyelashes.
Dominant males develop massive throat pouches and enormous cheek bulges, known as flanges, which they preserve for as long as they preserve a dominant position of their territory. They lose them if they’re dethroned.
Babies are born with a pinkish face that adjustments to a leathery brown as they age.
Sumatran Orangutan Daily Life and Group Dynamics
The Sumatran orangutan has 5 phases of life which might be characterized by completely different bodily and behavioral options.
The first of those phases is infancy, which lasts from beginning to around 2.5 years of age.
The orangutan weighs between 2 and 6 kilograms. A toddler is recognized by lightly pigmented zones across the eyes and muzzle in distinction to darker pigmentation on the remainder of the face in addition to long hairs that protrude outward across the face.
During this time, the toddler is all the time carried by the mom throughout travel, it’s extremely dependent on the mom for meals, and likewise sleeps within the mom’s nest.
The subsequent stage is known as juvenile-hood and takes place between 2.5 and 5 years of age. The orangutan weighs between 6 and 15 kilograms and doesn’t look dramatically completely different from an infant.
Although it’s nonetheless primarily carried by the mom, a juvenile will usually play with friends and make small exploratory journeys inside the vision of the mom.
Towards the top of this stage, the orangutan will cease sleeping within the mom’s nest and can construct its personal nest close by. From the ages of 5 to 8 years of age, the orangutan is in an adolescent stage of life.
The orangutan weighs around 15–30 kilograms. The light patches on the face begin to disappear, and ultimately the face turns fully dark.
During this time, orangutans nonetheless have fixed contact with their moms, but they develop a stronger relationship with friends whereas taking part in teams.
They are nonetheless younger and act with a warning around unfamiliar adults, particularly males. At eight years of age, feminine orangutans are thought of totally developed and start to have offspring of their very own.
Males, nevertheless, enter a stage known as sub-adulthood. This stage lasts from eight to around 13 or 15 years of age, and the orangutans weigh around 30 to 50 kilograms. Their faces are fully darkish, and so they start to develop cheek flanges.
Their beard begins to emerge, whereas the hair around their face shortens, and as an alternative of pointing outwards the face flattens alongside the skull.
This stage marks sexual maturity in males, but these orangutans are nonetheless socially undeveloped and can nonetheless keep away from contact with grownup males. Finally, male Sumatrans orangutans attain maturity at 13 to 15 years of age.
They are extraordinarily massive animals, weighing between 50 and 90 kilograms, roughly a load of a completely grown human.
They have a completely grown beard, totally developed cheek callosities, and long hair. These orangutans have reached full sexual and social maturity and now only travel alone.
Every day begins with a quest for meals at dawn upon waking. To discover their meals, orangutans often journey on their very own, besides moms who journey with their child and, probably, an adolescent.
Groups of younger women and men with no territory of their very own have been noticed touring collectively from one feeding station to a different.
Because fruit is especially ample in Sumatra, it isn’t uncommon to see a number of orangutans feeding on the identical tree at a similar time in mast fruiting intervals. Socialization is due to this fact a bit more frequent than in Borneo the place fruit is just not as ample.
Orangutans feed for a few hours then nap. Sumatran orangutans construct rudimentary nests for his or her siestas, whereas Bornean orangutans don’t.
After an hour of relaxation, they journey once more, selecting up meals gadgets alongside the way in which till they discover fruit bushes and resume consuming.
Their day ends around 5 p.m., once they accept the night and construct one other nest by bending massive branches and weaving smaller branches in to make a sturdy, comfy, rounded platform. If they sense a storm coming, they might even add a roof product of leaves.
The “pasha” or dominant male’s territory often spans as much as four sq. miles (10 km2). The females’ territories are nested inside his territory and span as much as 2 sq. miles (5 km2). The size of the territory relies on meal abundance.
Males defend the feeding areas the place females reside and thus not directly defend them from unflanged males that don’t have any territory of their very own and are transient. These males don’t have the bodily traits flanges of the dominant males (massive cheek and throat pouches).
An unflanged male might cross a feminine’s territory to go to his mom, to search for a territory he may declare, or searching for a possibility to mate. Females assaulted by an unflanged male scream loudly to call the dominant male and fiercely resist their assailant.
However, since orangutans transfer fairly slowly and the territory of every feminine is kind of massive, it may be troublesome for a dominant male to defend a distressed feminine and preserve unique mating rights.
Sumatran Orangutan Diet
Sumatran orangutans are primarily frugivores, favoring fruits consisting of a big seed and surrounded by a fleshy substance, comparable to durians, lychees, jackfruit, breadfruit, and fig fruits.
Insects are additionally an enormous part of the orangutan’s diet; essentially the most consumed sorts are ants, predominantly of the genus Camponotus (not less than 4 species indet.). Their principal diet may be damaged up into 5 classes: fruits, bugs, leaf materials, bark, and different miscellaneous meals gadgets.
Studies have proven that orangutans within the Ketambe space in Indonesia ate over 92 completely different sorts of fruit, 13 completely different sorts of leaves, 22 types of different vegetable materials comparable to top-sprouts, and pseudo-bulbs of orchids. Insects included within the diet are numbered not less than 17 differing types. Occasionally soil from termite mounds has been ingested in small portions.
When there’s low ripe fruit availability, Sumatran orangutans will eat the meat of the sluggish loris, a nocturnal primate. Water consumption for the orangutans was ingested from natural bowls created within the bushes they lived around. They even drank water from the hair on their arms when rainfall was heavy.
Sumatran Orangutan Fun Facts
Before Captain Beeckman printed “A Voyage to the Island of Borneo” in 1718, no westerner had ever heard of the clever red ape.
He referred to them in his writings as “Oran Ootan,” which is a direct phonetic translation of the Dayak phrases that means “person” and “forest.” He wrote that these creatures hid within the forest as a result of they have been as soon as people remodeled into beasts.
Specimens have been introduced back to England and different international locations to refill the royal menageries and their sight excited the crowds of the time. However, it was not till the 1960s that critical research of the species within the wild started.
Orangutans share 97% of their DNA with people.
Sumatran Orangutan Communication
Infants whine and entice their mom’s consideration with calls that allow her to know they need meals or assistance. Some females make distinctive sounds geared toward reassuring their offspring. It is believed that the sounds are handed down from mom to daughter.
Dominant males can produce a “long call” because of their throat pouches, which they use to draw females and inform different males to maintain their distance (a form of mediation tool to keep away from battle).
Baring of teeth and shaking branches clearly communicates to a rival that he must back off. Males additionally push tree snags (useless or dying bushes) over to make noise as a part of dominance shows.
Both women and men typically make a “kiss squeak” sound to threaten one other particular person.
Female encounters are often amicable. Adolescent females are essentially the most gregarious. They groom grownup males and one another. The behavior of feminine adjustments at the beginning of her first offspring when she turns into much less tolerant of others.
Sumatran Orangutan Reproduction and Family
Female orangutans mate with the dominant male of their territory. They have their first offspring at around 15 years of age and provides beginning each 5 to seven years.
They are most fertile when the fruit is ample, as bodies require numerous energy. After a feminine is impregnated, the male often leaves.
A rosy-faced child is born after a gestation interval of 227 to 270 days (7.5 to 9 months) and weighs Three lbs (1.Three kg). Twins are extraordinarily uncommon.
The teenager will develop to be 33 lbs (15 kg) by the age of three. Baby orangutans are very dependent on their moms for a long time. They spend not less than seven years together with her. For the first three years of their lives, they need fixed bodily contact with their moms.
This might be why toddler mortality may be very low within the wild. Young are nursed via the age of 5 and change into unbiased once they attain the ripe age of eight.
Males change into sexually mature at 15 and depart to be on their very own. Females change into sexually mature at 11, however stay with their moms a couple of more years to be taught the artwork of motherhood.
Female Sumatran orangutans sometimes reside 44–53 years within the wild, whereas males have a barely longer lifespan of 47–58 years. Females are capable of giving beginning as much as 53 years of age, primarily based on the research of menopausal cycles.
Both women and men are often thought of wholesome even on the finish of their lifespans and may be recognized as such by the common abundance of hair growth and sturdy cheek pads.
The Sumatran orangutan is more social than its Bornean counterpart; teams collect to feed on the mass quantities of fruit on fig bushes. The Sumatran orangutan community is finest described as free, not displaying social or spatial exclusivity. Groups usually encompass feminine clusters and a most popular male mate.
However, grownup males usually keep away from contact with different grownup males. Subadult males will attempt to mate with any feminine, though largely unsuccessfully since mature females are simply able to fend them off.
Mature females desire to mate with mature males. Usually, there’s a particular male in a gaggle that mature females will exhibit choice for. Male Sumatran orangutans typically have a delay of a few years within the improvement of secondary sexual traits, comparable to cheek flanges and muscle mass.
Males exhibit bimaturism, whereby totally flanged grownup males and the smaller unflanged males are each able to reproducing, however make use of differing mating methods to take action.
The common interbirth charges for the Sumatran orangutan is 9.3 years, the longest reported among the many great apes, together with the Bornean orangutan. Infant orangutans will keep near their moms for as much as three years.
Even after that, the younger will nonetheless affiliate with their moms. Both the Sumatran and Bornean orangutans are more likely to reside for a number of many years; the estimated longevity is more than 50 years.
The common of the first reproduction of P. abelii is around 15.4 years old. There is not an indication of menopause.
Conservation Status and Threats
Like all orangutans, Sumatran orangutans are Critically Endangered (IUCN, 2017). The International Union for Conservation of Nature Red List of Threatened Species signifies that their inhabitants have endured a substantial lack of people since 1985. Per the 2016 estimates, solely 13,000 people stay within the wild.