-Bornean: Pongo pygmaeus
-Sumatran: Pongo abelii
Sumatran orangutans are critically endangered; Bornean orangutans are endangered.
Where to see them:
Orangutans of Ketambe habitats, Asian Forest
Zoo Atlanta exhibits the nation’s largest zoological orangutan collection. Find out more at the Meet the Orangutans page
The orangutan is the largest tree-dwelling mammal in the world
The name “orangutan hutan” means “person of the forest” in the Malay language
Orangutans share 97 percent of their DNA with humans
Sumatran orangutans: Adult males average 4.6+ feet and weigh 150-200+ pounds; adult females, 3+ feet and 80 to 100 pounds.
Bornean orangutans: Adult males average 4+ feet and 130 to 165 pounds; adult females, 3.3+ feet and 70 to 100 pounds.
Bornean orangutans: Borneo, Indonesia
Sumatran orangutans: northern Sumatra, Indonesia
Bornean orangutans: tropical and subtropical moist broadleaf forests in Bornean lowlands; Bornean orangutans also inhabit mountainous areas with elevations as high as 1,500 meters.
Sumatran orangutans: lowland forests and peat swamp forests
Both Bornean and Sumatran orangutans generally live alone in the wild, but Bornean orangutans tend to be more solitary than do their Sumatran counterparts. The only long-term bonds orangutans have are those between a mother and her offspring. Wild orangutans will often encounter one another and just pass by peacefully unless the encounter is between two adult males. Males generally have a home range in which several females also live. However, adult males will not tolerate additional adult males in their home territory. Adult males communicate with each other over long distances using a vocalization called a long call.
Sumatran orangutans also spend more time in trees than do Bornean orangutans because of predation by Sumatran tigers.
Orangutan diet consists primarily of fruit, as well as shoots, seeds, leaves, bark and insects. Their preference for fruit is one of the reasons for their solitary behavior. Because fruit is seasonal and can be patchy, areas can not accommodate large groups. When fruit is plentiful, however, multiple females and their offspring have been known to gather together in one area.
Orangutan females generally give birth to their first offspring around the age of 15. Orangutan babies usually spend between 7 to 8 years with their mothers – the longest childhood of any mammal next to humans. This time is crucial because unlike other ape species, which live in groups in which juveniles learn from multiple adults, orangutans learn only from their mothers. Orangutan females also have very long intervals between births, giving birth only about once every eight years.
Wild orangutans generally live to be between 35 and 40 years old; orangutans in zoological settings can live into their 60s.
Some of My Neighbors (IN THE WILD)
Bornean orangutan: Asian elephant, Sumatran rhinoceros, clouded leopard, slow loris, Hose’s langur, gibbon, proboscis monkey, Prevost’s squirrel, mountain giant rat and silvered langur
Sumatran orangutan: Sumatran tiger, Sumatran rhinoceros, Sumatra water shrew, babirusa, Sumatran elephant, Sumatran striped rabbit, dhole, Dayak fruit Bat, Malayan tapir, Malayan sun bears and Bornean clouded leopard
Population Status & Threats
The Sumatran tiger is the Sumatran orangutan’s only natural predator; Bornean orangutans have no natural predators. The primary threat to orangutans is habitat loss due to human activities, such as logging, deliberate forest fires and timber clearing for farming. Other specific threats include clear-cutting of forests for palm oil plantations, encroachment of human settlements and hunting for meat and the illegal pet trade. The Cheyenne Mountain Zoo puts together an informative palm oil guide (PDF).
Sumatran orangutans currently number only around 6,500 individuals (2008) and could be extinct in the wild in as little as five years. Bornean orangutans are less endangered than Sumatran orangutans, numbering around 45,000 individuals (2008), but could be extinct in the wild within 10 years.
Zoo Atlanta Conservation Efforts
In 2008, Zoo Atlanta and the Ape Conservation Effort donated $6,000 to the Nyaru Menteng Orangutan Rehabilitation Center founded by Lone Droschler-Nielsen and Dr. Willie Smits. Funds were applied to urgently-needed medical supplies for sick and injured orangutans rescued from the pet trade and palm oil plantations. Nyaru Menteng is currently the largest orangutan rehabilitation center in the world and is home to over 650 orangutans.