In honor of the Phoenix Zoo's Bornean Orangutan, Duchess (pictured above) - who celebrated her 50th birthday on March 27, 2010 - I decided to do my first animal spotlight on Orangutans.
The name Orangutan comes from the Malay words 'orang' meaning person and 'hutan' meaning forest, or literally 'person of the forest'. And rightly named since Orangutans are the largest tree-dwelling species in the world. Orangutans have tremendous strength, which enables them to swing from branch to branch and hang upside-down from branches for long periods of time to retrieve fruit and eat young leaves.
Along with the bonobo, the chimpanzee, and the gorilla, the orangutan is remarkably similar to humans, in terms of anatomy, physiology, and behavior. In the wild, Orangutans have been observed making simple tools to scratch themselves. They also use leafy branches to shelter themselves from rain and sun, and sometimes even drape large leaves over themselves like a poncho. They have also been observed using branches as tools during insect foraging, honey collection, and protection against bees, and to fish for branches or fruit that is out of reach. Like humans, Orangutans have opposable thumbs which they use to hook onto branches, food and other things.
Fun Fact #1. Their big toes are also opposable.
Like the other great apes, Orangutans are highly intelligent, as seen in their advanced tool use and distinct cultural patterns. Their native intelligence is often used to solve problems related to tree-travel and food processing. In parts of Borneo, for example, orangutans have been seen using handfuls of leaves as napkins, wiping leftover food from their chins. Some Orangutans in parts of Sumatra, on the other hand, have been seen using leaves as gloves, helping them handle spiny fruits and branches, or as seat cushions in spiny trees.
Male orangutans are approximately twice the size of females, weighing over 200 pounds and reaching a height of up to 5 feet. The males have large cheek pads, which they develop at about 15 years of age, and a large pouch of skin under their chin. Both of which females, for some reason, find strangely attractive. Their arms can span as long as 7 feet from fingertip to fingertip, considerably longer than their height.
Orangutans are slow-growing animals and produce probably the lowest number of offspring over a lifetime, of all mammals. A female becomes sexually mature at the age of 10 and will remain fertile for the next 20 years. However they tend not to start reproducing until they are about 15 years of age. The average time between orangutan births for an adult female is eight years. As a result only 3 or 4 offspring are born during her lifetime.
The gestation period is between 235 and 270 days. A baby orangutan weighs about 3 pounds at birth. Infant mortality rates, due to natural causes, in the wild are extremely low. Orangutan mothers are very good at raising their babies to adulthood. The fact that the mother tends to keep her offspring with her for an average of eight years has everything to do with the low infant mortality rate. Offspring will become completely independent by the age of 10.
Infants are carried continuously by the mother for the first year and whenever the mother travels until the age of 4. Mother orangutans are very patient with their offspring and it will sleep in its mothers nest until it is weaned at about the age of 3 to 4 years old. They will often stay near and dependent upon their mother for 7 to 8 years while they learn to navigate through the dense forest in search of the hundreds of different edible foods.
Fun Fact #2.Adolescent males usually break ties with their mothers, but adolescent females return frequently to spend time around their mothers.
Orangutans do not live in the big family groups that most other primates do. This is mainly thought to be a result of the small amounts of food available to them in one area, therefore it is to their advantage to be in smaller groups. In Borneo it is also not uncommon to see an Orangutan living by themselves. If Orangutans are seen living together it is usually only in a closely-knit family consisting of perhaps mom and child as well as maybe older siblings living together with mom.
Although orangutans are generally passive, aggression toward other orangutans is very common; they are solitary animals and can be fiercely territorial. Immature males will try to mate with any female, and may succeed in forcibly mating with her if she is also immature and not strong enough to fend him off. Mature females easily fend off their immature suitors, preferring to mate with a mature male. Orangutans have the highest rate of forced mating - particularily in Borneo - than any other animal. This fact can be contributed to their solitary living situations where a lot of females are not protected from these immature males.
The lifespan of an orangutan in the wild is estimated from about 35 to 40 years, although we're not absolutely sure about this number since many Orangutans are hunted, captured as pets, or their habitat is destroyed. In captivity they can live to 50 years, though there are some that have lived longer. The oldest living Orangutan right now is Duchess, a 50 year-old Bornean Orangutan, who lives at the Phoenix Zoo.
Fun Fact #3. The oldest recorded Orangutan, a Sumatran Orangutan named Non-ja (pictured above), lived to a ripe age of 55 years. She died though in December of 2007 at the Miami Metro Zoo.
Orangutans are an endangered species as their habitat has been rapidly destroyed by palm oil production, logging and other ventures. Their slow reproduction rate has also contributed to the fact of these animals becoming and staying on the endangered list. While they were once thought to live in rainforests spaning from China all the way down to Java, Orangutans are now only found on two islands in Southeast Asia - Borneo and Sumatra.
Bornean Orangutans are classified as Endangered and Sumatran Orangutans are classified as Critically Endangered on the IUCN Red List of Threatened Species and their numbers are continually decreasing. Laws are in place to protect these animals from poaching and illegal logging but unfortunately both practices still continue and threaten the survival of this beloved animal. The forests which house the Orangutans are also under pressure from a need to rebuild in Malaysia and Indonesia because of the effects of the Tsunami in 2004.
Conservation actions are taking place with the Leuser Ecosystem and other small oraganizations who are putting forth an effort to rehabilitate and re-introduce rescued Orangutans that have been captured and kept as pets. It is not expected though for these animals to be removed from the endangered list anytime in the near future.
Because of Conservation efforts from individuals, public zoos, and governments, these lovely primates can still be enjoyed in our world today.
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