Bornean Orangutan, Pongo pygmaeus
Bornean Orangutan
Pongo pygmaeus
Geographic Distribution and Habitat
The Bornean orangutan (Pongo pygmaeus) is one of three orangutan species; each is classified as a great ape and they are the only great apes native to Asia. Inhabiting equatorial Borneo, the world’s third-largest island, encompassing the countries of Indonesia (home to the species’ greatest population), Malaysia, and Brunei, Bornean orangutans live in lowland and hilly tropical and subtropical rainforests at elevations up to 2,625 feet, or a half-mile (800 m), above sea level. They make the rainforest canopy their home.
Sumatran orangutans (Pongo abelii), who inhabit the island of Sumatra, belong to the second orangutan species. Tapanuli orangutans (P. tapanuliensis), who inhabit the region of Batang Toru within Sumatra, belong to the third species.
Both the Bornean orangutan and Sumatran orangutan were once considered to be subspecies of the same species. Extensive genetic research revealed otherwise: these two great apes diverged from one another about 400,000 years ago, with only a low-level gene flow remaining today. In 1996, each was recognized as a distinct species. Then, in November 2017, following detailed evolutionary studies, along came the Tapanuli orangutan, announced as a distinct species.
Three subspecies of the Bornean orangutan are currently recognized:
- Northwest Bornean Orangutan (P. p. pygmaeus):
Inhabits the state of Sarawak (Malaysia) and the province of West Kalimantan (Indonesia). - Northeast Bornean Orangutan (P. p. morio):
Inhabits the state of Sabah (Malaysia), the province of North Kalimantan (Indonesia), and the province of East Kalimantan (Indonesia). - Southwest Bornean Orangutan (sometimes called the Central Bornean Orangutan) (P. p. wurmbii):
Inhabits the province of West Kalimantan (Indonesia) and the province of Central Kalimantan (Indonesia).
A taxonomic debate is ongoing. Some scientists believe that the Southwest Bornean orangutan is more closely related to the Sumatran orangutan than to the Bornean orangutan. But for now, the Bornean orangutan remains the “parent” to three “children.”
Size, Weight, and Lifespan
As the third-heaviest living nonhuman primate, after the Eastern Gorilla (Gorilla beringei) and Western Gorilla (Gorilla gorilla), the Bornean orangutan is the largest arboreal (tree-dwelling) mammal.
Standing upright at about 3.2 feet (97 cm) tall and weighing between 132 to nearly 200 pounds (60–90 kg), fully grown males are much large than fully grown females. Adult females stand at about 2.5 feet (78 cm) tall and weigh between 88 and 110 pounds (40–50 kg). (This size difference is an example of sexual dimorphism, when significant physical differences beyond sexual organs distinguish the male and female sex of a species.)
Because orangutans have exceedingly slow metabolisms relative to their large body size, those in captivity are at risk of becoming grossly overweight. Unlike orangutans in the wild who rely on their bodies’ ability to store fat, which sustains them when food sources in their environment become scarce, captive members don’t have to worry about their next meal—or a place to sleep. They are fed regularly by their keepers and are provided with sleeping quarters. Factor in a more sedentary lifestyle than that of their wild brethren who must forage for their food and build nightly sleeping nests (thereby expending calories), extra pounds on the frames of captive individuals are not surprising.
In the wild, Bornean orangutans live 35 to 45 years. The lifespan of captive individuals is reported as 60 years.
Consortship:
A short-term (up to two weeks) mating relationships observed in many group-living primate species that lack long-term mating relationships.
Curmudgeon:
A cranky, ill-tempered individual.
Subcutaneous:
Beneath the skin.
Visit the Glossary for more definitions
Appearance
A coarse, shaggy reddish coat, reminiscent of an overcoat plucked from a thrift store, covers the body of this great ape. Droopy breasts with dramatically protruding nipples help to distinguish adults from subadults. Incredibly long arms are one-and-a-half times longer than the legs. Shoulders are wider than hips.
The face, ears, palms, and soles of feet are bare of hair. Fingers and toes are long and curved. Mother Nature took away their tail about 25 million years ago during the evolution of all great apes—which includes us humans! If you could peek inside the mouth of an adult orangutan, you’d find 32 teeth—same as us. As with all primates—both nonhuman and human—orangutans have fingernails and toenails (rather than claws), and they have individualized fingerprints and toeprints that can be used for identification purposes during field studies.
Orangutans have a broad, human-like face. Compared to chimpanzees and gorillas, their brow ridge is modest. The nose is small, as are their unlobed ears. The bare facial skin of Bornean orangutans is black in adults and pinkish around the eyes and muzzle of younger individuals. Both adult males and females have a fleshy sac, somewhat resembling a stuffed purse, that hangs from their throats (much more pendulous in flanged males). Adult males sport prominent mustaches and beards.
Like all three orangutan species, the faces of some fully mature adult males are graced with flappy cheek pads composed of subcutaneous fibrous tissue known as “flanges.” Apparently, lady orangutans find these jowled males irresistible. Adult males who lack flanges are less desirable to the female persuasion.
The scientific name for this phenomenon—flanged vs. unflanged—is known as “bimaturism.” Flanges take years to develop. Or they might not develop at all. Unflanged adult males, who are smaller in size than their flanged male counterparts, are said to be in a state of “arrested development.” (A detailed study of both Bornean and Sumatran orangutans found that the Sumatran population is more prone to this condition, which may be linked to the dynamics associated with a constant stream of transient males.) Most scientists posit that, eventually, these flappy cheek pads will grace the faces of all flange-free adult males. Ultimately, Mother Nature decides.
As a secondary sexual characteristic of mature males, flanges had long been thought to be associated with a male’s increasing testosterone levels. Social interactions, energy level, and an individual’s overall physiological condition (including hormonal) have been hypothesized as additional contributing factors.
More recent research shows that both flanged and unflanged males have the same testosterone levels, thereby deflating the testosterone theory. However, flanged males may have higher levels of the stress hormone cortisol in their bodies, indicative of severe stress experienced by these great apes throughout their development. Particular to flanged males are deep ring-like defects in their tooth enamel. Scientifically named “linear enamel hypoplasia” (LEH), this condition is known to be a life stress indicator. (Remember this term for when you are playing a Trivia game!)
Researchers were intrigued: why do flanged males exhibit greater stress markers than unflanged males? Do these two male counterparts experience stress differently? Deeper studies led researchers to conclude that the developmental arrest of unflanged males is not a response to having experienced stress; rather, it is an adaptation of these great apes to avoid the physiological impacts associated with chronic stress and/or experiencing lower stress levels. Does this mean that unflanged males are more Zen? Scientific studies await.
But enough (for the moment) about flanged males. Segue to those who are truly irresistible: baby orangutans! Wiry and unkempt hair, big and soulful eyes, ears you want to gently tweak, and expressive faces that can melt a curmudgeon’s heart make these little ones the darlings of all great ape babies. Who needs flanges when you are this cute?
Diet
Overall, the diet of Bornean orangutans includes 400 to 500 different types of food. They especially love their fruits, which comprise 60 percent of their diet, making these great apes a predominantly “frugivorous” species. Wild figs and durians (an odorous fruit with spiked protuberances) are favorites. Various leaves, shoots, tree bark, honey, insects, and bird eggs are also on the menu. And they intentionally eat soil and small rocks. This proclivity is a recognized behavior known as “geophagy,” common among other great ape species, and provides Bornean orangutans with the minerals not found in their largely frugivorous diet. The practice also helps to absorb toxins and provides other intestinal benefits, including combating diarrhea. For medicinal purposes, Bornean orangutans chew on the leaves of a local plant (Dracaena cantleyi), same as the indigenous people do, to produce a soapy lather that they spread on their skin for relief of joint and muscle inflammation.
Bornean orangutans’ natural instinct is to eat often—and a lot. These intense foragers depend on the island’s many fruit trees to provide them with much of their sustenance and to fulfill their bodies’ energy requirements. Glucose (plant sugar) in their bloodstream converts to energy. So, when fruits are out of season, the energy level of these great apes becomes negatively impacted. Mother Nature to the rescue. Magical molecules called “ketones,” produced from fatty acids in the liver, break down the generous fat storage in the orangutans’ bodies and convert to energy (another Trivia tidbit!).
Not all scientists are fully convinced that fruit availability is a significant (or sole) indicator of energy intake and balance, however. These scientists cite differences in energy levels among flanged males, unflanged males, and adult females—these levels may be linked to different foraging strategies. There appears to be scientific agreement, though, that orangutans experience greater periods of negative energy balance, as compared to African apes. This distinction is important in understanding orangutan behavior and socioecology and, scientists say, is likely a key factor in the evolutionary divergence of orangutans and African apes.
Behavior and Lifestyle
Orangutans have earned the distinction as being among the most intelligent nonhuman primates. These self-aware beings are capable of reasoning. They possess superb engineering skills, evidenced by their nightly nest building; exhibit proficiency with tools, using branches to test water depth and to poke termite holes when in the mood for a termite snack; and demonstrate innovation by creating “umbrellas” out of leaves to keep themselves dry during heavy rainfalls. Their ability to solve abstract problems and even learn human sign language has been demonstrated in studies of captive orangutans. Not quite as strong as their gorilla cousins, orangutans are about seven times stronger than humans (beyond that when compared to couch potato humans). Scientists have also found that orangutans possess a sense of empathy.
They are diurnal creatures (active during daylight hours) who spend most of their time in trees (making them arboreal). In fact, orangutans are the only primarily arboreal great apes and are nature’s largest tree-dwelling mammals.
Assisted by their broad shoulders and strong arm muscles, Bornean orangutans easily (albeit not gracefully) swing from tree to tree, their heavy weight causing trees to sway. Their exceptionally long arms allow them a reach of 6.5 to 8 feet (2–2.5 m). Mobile hips and flexible knee and ankle joints help them to jump and stick their landing, while their hands and feet allow them to grasp branches. Assisted by opposable thumbs and big toes, orangutans can hang from a branch with one hand while feeding themselves with the other hand, or hang upside-down by their feet! They can also carry large fruits in their mouths while swinging from tree to tree.
Their sensitive lips allow them to detect food textures before taking a bite. Powerful jaws crack, crush, and chew through nuts, tree bark, and spiny-covered fibrous fruits. Their fingernails help to open stubborn nuts and, of course, assist with an itch that needs to be scratched!
Although they spend more than 90 percent of their time in the trees, Bornean orangutans once in a while descend to the forest floor, more so than Sumatran populations. Unlike chimpanzees and gorillas who walk on their knuckles, orangutans walk on their fists with the weight of their bodies borne by the largest bones in their toes—called the “proximal phalanges” (again, retrieve this tidbit for when you play primate Trivia!).
A typical day for Bornean orangutans begins with two to three hours of eating, followed by a noontime nap and afternoon travel, and ends with nest-building during the early evening. Each night in a new location, they construct an elaborate nest high in the treetops using branches and foliage to create a makeshift mattress, pillow, and roof to protect them from rain. And hopefully, they remain undetected by predators.
Fortunately, their large size and arboreal lifestyle make orangutans an unlikely prey species of natural predators. But with their habitats shrinking, food sources dwindling, and Nature becoming more out of balance, these great apes are becoming more exposed—particularly when they are forced to the ground to forage for food. Potential predators include clouded leopards, who hunt and ambush at night while the orangutans are sleeping. But these big cats prey mostly on deer, wild pigs, monkeys, and squirrels. (Sumatran orangutan populations also have to look over their shoulders for lurking tigers.) Tree pythons are another potential threat. These large snakes are able to wrap themselves around an orangutan’s body . . . and squeeze. By far, humans are the main predator threat to Bornean orangutans. These great apes’ large size and languid movements make them easy targets for hunters.
Orangutan means “person of the forest” in the native languages of Indonesia and Malaysia.
Orangutans share approximately 97 percent of their DNA with human primates.
Bornean orangutans are independent, predominantly solitary creatures—more so than Sumatran populations and other great apes. But they aren’t antisocial. When home ranges overlap, as is often the case, particularly with females who live with their offspring (one or two), they are often cordial with one another—and will politely forage alongside one another, such as when raiding a fruit tree. Females may even form social bonds with females from other defined home ranges. Within these overlapping home ranges resides a dominant male, who is the primary breeding partner for all the females within the overlapping ranges. Flanged males are often hostile to other flanged males—though they are usually tolerant of unflanged males, whom flanged males regard as a lesser threat to their flanged machismo. Unflanged males are peaceful in their interactions with one another.
Mothers form strong bonds with their offspring, even after their young are weaned and become independent, between 8 and 11 years of age. Males are the first to strike out on their own, but they return home often to visit mom (think of young adult men who come home so mom can do their laundry!). Females remain with their mothers until their teen years, in part so they can learn essential parenting skills for when they become mothers themselves one day. When they finally leave home, females do not venture far. Orangutan males remain transient until they are able to successfully displace a dominant, adult male from his home range.
Other primate species who make Borneo their home include gibbons, pig-tailed macaques, proboscis monkeys, leaf monkeys, western tarsiers, and slow lorises. Non-primate residents include clouded leopards, Asian pygmy elephants, sun bears (the smallest of all the world’s bears!), bearded pigs, warthogs, sambar deer, banteng (also known as tembadau, a species of wild cattle), and flying frogs. More than 420 species of birds—including ospreys, egrets, and kingfishers—live here, too.
Orangutan vocalizations include consonant- and vowel-like components, same as human language. Male orangutans are more vocal than females, and flanged males are even more vocal—and louder—than unflanged males, thanks to much larger, more pendulous throat sacs. As they vocalize, these sacs inflate, enabling flanged males to emit a long note that carries up to 1 mile (1,600 m). Their long note (beginning with grumbles, peaking with pulses, and ending with bubbles) announces their virility and is intended to attract receptive females. To warn of danger, flanged males emit deep, throaty grunts.
Both males and females communicate with one another through what is known as a “rolling call,” a series of low-frequency sounds. When uncomfortable with a situation, they emit a “kiss squeak,” a sound made by sucking in air through pursed lips. They might smack their lips together while building their nightly nest. Mothers emit “throat scrapes” to keep in contact with their offspring, and infants emit soft hoots when upset.
Like human primates, orangutans use postures and gestures to convey mood or to make a point. “Hissy fits” are not exclusive to humans. These great apes might stomp their feet or shake an object to indicate displeasure.
The interplay between mothers and infants is especially pronounced. A mother might present her backside as an invitation for her little one to climb aboard, or she might gesture for her little one to stop unruly behavior. Little ones whimper or cry when they are hungry, and they signal their mothers they want to play.
Orangutans do not have “poker faces,” and Bornean orangutans are no exception. Their exaggerated facial expressions convey sadness, joy, confusion, levity, fear—and many other emotions shared with humans.
Scent communication plays a lesser role in their interactions with one another, though a strong musky odor permeates from their bodies; it is especially pungent in adult males and may be a kind of aphrodisiac that attracts females.
When choosing desirable foods, orangutans rely on their sense of smell. And wildlife rehabilitators have successfully used aromatherapy to treat orangutans who are recovering from various traumas.
Social grooming—common with most nonhuman primates—is uncommon among orangutans. Perhaps this “anomaly” can be attributed to their mostly solitary lifestyle.
Females attain sexual maturity (able to conceive and bare young) between 11 and 15 years of age, earlier for those in captivity. Age of sexual maturity for males ranges widely; the transition from adolescence to undeveloped (unflanged) adulthood occurs between 7 and 10 years of age. Full development (flanged) could take another 10 years or more. But because unflanged males have the same levels of testosterone as flanged males, they are capable of siring young. As with females, captive males tend to reach sexual maturity earlier than those in the wild.
Researchers are currently examining the relationship between a female’s menstrual cycle and reproductivity patterns. Mating in the wild occurs most often when a female’s estrogen levels are high and when fruits are, simultaneously, readily available in large quantities.
Females usually give birth for the first time at about 15 years of age. After a gestation period (pregnancy) of about 8 months, female Bornean orangutans give birth to a single infant. A mother carries her baby for the first two or three years of her baby’s life and nurses her child for six to seven years. Mothers teach their young how to forage along with other essential survival skills. They teach their daughters parenting skills. Fathers do not help with child-rearing. But they don’t kill children either. Unlike some great apes, orangutans do not practice infanticide (killing infants sired by other males to force the mother into estrus more quickly), likely due to their low population and the long period between births. Of all mammal species, orangutans are the slowest to breed, with an eight-year interval between births.
The mating system of Bornean orangutans could be classified as usually polygynous (i.e., a pattern of mating where a male animal has multiple female mates)—with nuances. It’s more of an intrasexual competition among flanged males.
Vying for Female Attention
Females prefer dominant flanged males as mating partners. Should fully flanged males find themselves vying for the attention of a potential female mating partner, they try intimidating the other. If this strategy fails, encounters can turn violent. Male combatants might fight for a few minutes or an hour or longer, causing minor to severe injuries to the other. Missing fingers, healed scars on their faces and heads, or even a missing eye are common in nearly all fully-flanged males. Orangutan females possess a sense of decorum and civility. They rarely engage in the type of violent aggression as practiced by combating flanged males; therefore, their bodies are unmarred by war wounds.
Unflanged males tend to lurk in the distance, keeping to a perimeter of 44 to 55 yards (40–50 m), during a flanged male’s consortship with a sexually receptive female. Perhaps they are hoping for an opportunity. Should an unflanged male find a female alone, he is likely to force himself upon her in copulation. But rape isn’t exclusive to unflanged males. Researchers have documented cases where flanged males have forced themselves upon unwilling females.
Bornean orangutans are sometimes referred to as the gardeners of their forests. These great apes are vital to their rainforest ecosystem. Thanks to their largely frugivorous diet, the seeds of the many fruits they’ve eaten pass through their gut and are excreted in their fecal matter, from which these seeds germinate and grow. You might expect these large animals to have large poops—and they do. Good thing. Excited scientists conducting field research reported 828 seeds in one pile of Bornean orangutan poop! Some of these seeds were nearly 1 inch (2.5 cm) in length, indicative of the larger seeds and fruits that these great apes are able to ingest and process, a feat that smaller primates are unable to do.
Scientists have found that seeds handled by orangutans have greater germination success, as compared to seeds with no orangutan contact. It’s not just through defecation that they yield successful germination. Sometimes, these large primates spit. These spat-out seeds find their way to the forest floor where they propagate.
But scientists are worried. Should these emblematic great apes of Borneo become extinct, their absence from our world would not be the only tragedy. The diversity of Borneo’s rainforest forest ecosystem would also suffer . . . and slowly die.
In July 2016, the Bornean orangutan was up-listed from Endangered to Critically Endangered by the International Union for Conservation of Nature (IUCN, 2016), appearing on the IUCN Red List of Threatened Species. The species shares this ignoble status with both the Sumatran and Tapanuli orangutans.
After examination of population density and geographic range, the IUCN places the total Bornean orangutan population at 104,700 individuals (corroborated by a 2022 World Wildlife Fund)—compared to 230,000 a decade ago and over 300,000 in the 1970s. Fewer than 14,000 Sumatran and 800 Tapanuli orangutans remain.
Facing an extremely high risk of extinction in the wild, the foremost threat to the Bornean orangutan’s survival is habitat loss, driven by illegal logging and from the slashing and burning of forests to transform habitat into palm oil plantations. The palm oil industry is directly linked to deforestation, habitat degradation, climate change, animal cruelty, and indigenous rights abuses—all to create a cheap, ubiquitous ingredient found in a myriad of products, from cookies to cosmetics to detergents.
According to the World Wildlife Fund, an area the equivalent size of 300 football fields of rainforest is cleared each hour to make way for palm oil production. And according to a 2021 report by the Environmental Investigation Agency (EIA), nearly two million acres of habitat have been destroyed in Indonesia since 2016. Large-scale deforestation is pushing the Bornean orangutan to extinction. Populations are predicted to decline as much as 86 percent by 2025—should this devastating habitat loss continue.
Wildfires pose another risk, forcing orangutans into human settlements where these great apes are regarded as pests and are killed. Political unrest in Indonesia, poverty, and starvation are additional contributors to the Bornean orangutan’s demise. These dire factors have led indigenous people to hunt these primates for their flesh, known as “bushmeat.” Farmers kill these orangutans when they venture into agricultural areas—stolen orangutan habitat—in search of food. These animals are also killed for sport. The EIA estimates that more than 2,000 orangutans are hunted annually. Unfortunately, illegal killings of orangutans, often gruesome, largely go unpunished or are treated as minor infractions. According to a 2020 report by the scientific consultancy group Borneo Futures and the conservation nonprofit Wildlife Impact, less than 1 percent of reported orangutan-related crimes end in conviction.
Indonesia’s thriving—and illegal—wildlife pet trade depends on a steady supply of infants, furnished by orphaned babies (their mothers having been killed). These orangutan babies might be kept locally or smuggled abroad to other Asian countries, to the Middle East, and to Europe. But once they outgrow their cuteness stage and become difficult and more costly to care for, they often end up at rescue centers and sanctuaries—dropped off by frazzled owners who face no consequences (thus, no deterrence) for having illegally purchased and kept these primates. Facilities caring for these former pets are currently overrun, and staff face the daunting task of rehabbing and releasing all the orangutans—impossible because of a dwindling habitat that cannot accommodate over a thousand individuals.
Furthermore, Bornean orangutan populations living in small patches of forest are isolated from other populations, thereby prohibiting successful reproduction. And because female orangutans only give birth every 8 years, orangutan populations take years to restore after natural disasters and human encroachment.
Of course, the earth’s human-induced climate crisis is a specter that looms over the species. Indonesia’s stance that business development trumps the preservation of forests worsens the situation for orangutans. Following the 2021 global summit in Scotland, Indonesia’s environmental minister “tweeted” that business development “should not be stopped in the name of carbon emissions or in the name of deforestation” (reported by National Geographic, November 2021).
International trade of Bornean orangutans is banned under its listing in Appendix I of the Convention on International Trade in Endangered Species (CITES), an international agreement between governments whose goal is to ensure that international trade in specimens of wild animals and plants does not threaten their survival.
While in theory, much of the Bornean orangutan’s habitat is protected by Indonesian, Malaysian, and Brunei governmental laws, enforcement is difficult. Violation of laws prohibiting the killing or trafficking orangutans is largely treated as a non-issue by local government officials—despite the CITES agreement.
A 10-year national orangutan conservation plan, established in 2007, expired in 2017 without having achieved its conservation goals. A new plan was formulated in 2019 and abandoned shortly thereafter by government officials—an action that the EIA calls a “willingness to accept” orangutan deaths.
Conservationists say that the best way to save the species is by protecting and patrolling orangutan habitat. Connecting forest fragments so that populations can breed is another proven conservation strategy. And wildlife protection laws must be fully enforced.
While the situation of orangutans is heartbreaking, the plethora of conservation groups committed to ensuring these great apes’ survival is heartening—and offers hope.
Orangutan Foundation International (OFI) has its headquarters in Los Angeles, California. Founded by Dr. Birutė Galdikas, one of three anthropologists (The Trimates) to study great apes under the guidance of Dr. Louis Leakey, OFI continues to rescue and rehabilitate orangutans, preparing them for release back into protected areas of the Indonesian rain forest. In addition, OFI promotes the preservation of rainforest habitats. Originally called the Orangutan Research and Conservation Project, OFI was founded by Galdikas and former husband Rod Brindamour in 1986.
Founded in 1990, the Orangutan Foundation is a United Kingdom-based charity and is the foremost orangutan conservation organization working actively across the range of both orangutan species. Its primary focus is protecting forest habitat so that orangutans have the best chance of survival in the wild. The foundation also works with local communities to promote research and education, so that indigenous people recognize that orangutans are essential citizens, through their role as seed dispersers, who nourish the habitat that is shared by the Bornean people and these great apes.
International Animal Rescue (IAR) operates The Orangutan Conservation Center, established in 2013, in the province of West Kalimantan, Borneo. In addition to the rescue and rehabilitation of individual animals with a goal of reintroducing them into the wild, IAR’s multifaceted approach includes the protection of forest habitat, reforestation initiatives, community outreach and education, collaboration with stakeholders to secure both the long-term future of the species, and that of local communities, and preserving the forest habitat that both animals and people depend on for their survival.
Borneo Orangutan Survival Foundation (BOSF) runs the world’s two largest orangutan rescue centers, caring for who have either been displaced from natural habitat or have been orphaned, illegally captured, and held as pets. The ultimate goal is to successfully reintroduce the orangutans into safe suitable habitat where they can live an independent life.
The Orangutan Project is a volunteer-driven organization that raises funds for orangutan conservation projects in Borneo and Sumatra. It is major supporter of the BOSF.
World Orangutan Events is “a non-partisan initiative to promote orangutan conservation and welfare, as well as inter-organization cooperation.” Orangutan Caring Week and International Orangutan Day (August 19) are two examples of this initiative’s world-wide events to raise awareness.
Both the Sumatran Orangutan Society and Rainforest Alliance are two conservation groups focused on developing sustainable, deforestation-free palm oil production. Besides preserving orangutan habitat and saving the three species from extinction, this initiative empowers local citizens and helps them earn an income without exploiting forest resources.
The World Wildlife Fund has been working on orangutan conservation since the 1970s. The organization’s efforts include preserving orangutan habitat, antipoaching initiatives, sustainable forestry and agriculture, and ending the illegal pet trade.
- http://www.iucnredlist.org/details/17975/0
- https://orangutan.org/orangutan-facts/orangutan-behavior
- https://savegporangutans.org/orangutans/about-orangutans
- http://www.worldwildlife.org/species/bornean-orangutan
- https://pubmed.ncbi.nlm.nih.gov/31986816
- https://seaworld.org/animals/all-about/orangutans
- https://www.orangutans-sos.org/learn/palm-oil
- https://www.rainforest-alliance.org
- https://orangutan.org/the-joy-of-scent
- https://www.thegreatprojects.com/blog/scent-enrichment-for-bornean-orangutans
- https://www.orangutanrepublik.org/learn/orangutan-specifics/relationships-mating-strategies
- https://link.springer.com/article/10.1186/1742-9994-10-12
- https://phys.org/news/2018-01-orangutans-people-medicinal-joint-muscle.html
- https://orangutan-world.com/orangutan-predators
- https://www.orangutans-sos.org/learn/about-orangutans
- https://www.wwf.org.uk/learn/fascinating-facts/orangutans
- https://www.orangutantrekkingtours.com/orangutan-blog/how-many-critically-endangered-bornean-orangutans-are-left
- https://ielc.libguides.com/sdzg/factsheets/orangutans/population
- http://wildlifeimpact.org/wp-content/uploads/2020/01/Borneo-Orang-report_ENG-2020.pdf
- https://www.discoverwildlife.com/news/why-are-scientists-so-interested-in-orangutan-poo https://news.mongabay.com/2016/07/bornean-orangutan-declared-critically-endangered-as-forests-shrink
- http://blogs.scientificamerican.com/extinction-countdown/bornean-orangutan-critically-endangered
- http://www.orangutan.org.uk
- http://www.worldorangutanevents.org
- http://www.npr.org/sections/thesalt/2013/07/25/205486197/palm-oil-in-the-food-supply-what-you-should-know
- https://www.wwf.org.uk/learn/fascinating-facts/orangutans
- https://en.wikipedia.org/wiki/Bornean_orangutan
- https://orangutan.org/
Written by Kathleen Downey, October 2022.