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Kalimantan Borneo Orangutan Indonesia
The orangutans
are two species of great apes known for their
intelligence, long arms and reddish-brown hair. Native to
Indonesia and Malaysia, they are currently found only in
rainforests on the islands of Borneo and Sumatra, though
fossils have been found in Java, Vietnam and China. They
are the only surviving species in the genus Pongo and the
subfamily Ponginae (which also includes the extinct genera
Gigantopithecus and Sivapithecus). Their name derives from
the Malay and Indonesian phrase orang hutan, meaning
"person of the forest.
Etymology
The word orangutan (also written orang-utan, orang utan
and orangutang) is derived from the Malay and Indonesian
words orang meaning "person" and hutan meaning
"forest", thus "person of the forest". Orang Hutan is
the common term in these two national languages, although
local peoples may also refer to them by local languages.
Maias and mawas are also used in Malay, but it is unclear
if those words refer only to orangutans, or to all apes in
general.
The word was first attested in English in 1691 in the form
orang-outang, and variants with -ng
instead of -n as in the Malay original are found in many
languages. This spelling (and pronunciation) has remained
in use in English up to the present, but has come to be
regarded as incorrect by some.
The name of the genus, Pongo, comes from a 16th century
account by Andrew Battell, an English sailor held prisoner
by the Portuguese in Angola, which describes two
anthropoid "monsters" named Pongo and Engeco. It is now
believed that he was describing gorillas, but in the late
18th century it was believed that all great apes were
orangutans; hence Lacépède's use of Pongo for the genus.
Ecology and appearance
Orangutans are the most arboreal of the great apes,
spending nearly all of their time in the trees. Every
night they fashion nests, in which they sleep, from
branches and foliage. They are more solitary than the
other apes, with males and females generally coming
together only to mate. Mothers stay with their babies
until the offspring reach an age of six or seven years.
There is significant sexual dimorphism between females and
males: females can grow to around 4 ft 2 in or 127
centimeters and weigh around 100 lbs or 45 kg, while fully
mature males can reach 5 ft 9 in or 175 centimeters in
height and weigh over 260 lbs or 118 kg.
Fully mature
males can be distinguished by their prominent cheek
flanges and longer hair.
Bimodal Male Development
Adult male orangutans exhibit two modes of physical
development, flanged and unflanged. Flanged adult males
have a variety of secondary sexual characteristics,
including cheek pads (called "flanges"), throat pouch, and
long fur, that are absent from both adult females and from
unflanged males. Flanged males establish and protect
territories that do not overlap with other flanged males'
territories. Adult females, juveniles, and unflanged males
do not have established territories. A flanged male's
mating strategy involves establishing and protecting a
territory, advertising his presence, and waiting for
receptive females to find him. Unflanged males are also
able to reproduce; their mating strategy involving finding
females in estrus and forcing copulation. Males appear to
remain in the unflanged state until they are able to
establish and defend a territory, at which point they can
make the transition from unflanged to flanged within a few
months. The two reproductive strategies, referred to as
"call-and-wait" for flanged male and "sneak-and-rape" for
the unflanged male, were found to be approximately equally
effective in one study group in Sumatra,[9] though this
observation did occur during a period of instability in
flanged male rank and unflanged male mating success may be
lower in Borneo.
Diet
Orangutans eat mostly fruit which makes up 60% of their
diet. Fruits with sugary or fatty pulp are favored. The
fruit of fig trees are also commonly eaten since it is
easy to both harvest and digest. Other food items include:
young leaves, shoots, seeds and bark. Insects and bird
eggs are also included.
Orangutans are thought to be the sole fruit disperser for
some plant species including the climber species Strychnos
ignatii which contains the toxic alkaloid strychnine.
It does not appear to have any effect on orangutans except
for excessive saliva production.
Behavior and language
Orangutans at Singapore Zoo
Like the other great apes, orangutans are remarkably
intelligent. Although tool use among chimpanzees was
documented by Jane Good all in the
1960s, it was not until the mid-1990s that one population
of orangutans was found to use feeding tools regularly. A
2003 paper in the journal Science described the evidence
for distinct orangutan cultures.
According to recent research by Harvard University
psychologist, James Lee, orangutans are the world's most
intelligent animal other than humans, with higher learning
and problem solving ability than chimpanzees, which were
previously considered to have greater abilities. A study
of orangutans by Carel van Schaik, a Dutch primatologist
at Duke University, found them capable of tasks well
beyond chimpanzees’ abilities — such as using leaves to
make rain hats and leak proof roofs
over their sleeping nests. He also found that, in some
food-rich areas, the creatures had developed a complex
culture in which adults would teach youngsters how to make
tools and find food.
A two year study of orangutan symbolic capability was
conducted from 1973-1975 by Gary L. Shapiro with Aazk, a
juvenile female orangutan at the Fresno City Zoo (now
Chaffee Zoo) in Fresno, California. The study employed the
techniques of David Premack who used plastic tokens to
teach the chimpanzee, Sarah, linguistic skills. Shapiro
continued to examine the linguistic and learning abilities
of ex-captive orangutans in Tanjung Puting National Park,
in Indonesian Borneo, between 1978 and 1980. During that
time, Shapiro instructed ex-captive orangutans in the
acquisition and use of signs following the techniques of
R. Allen and Beatrix Gardner who taught the chimpanzee,
Washoe, in the late-1960s. In the only signing study ever
conducted in a great ape's natural environment, Shapiro
home-reared Princess, a juvenile female who learned nearly
40 signs (according to the criteria of sign acquisition
used by Francine Patterson with Koko, the gorilla) and
trained Rinnie, a free-ranging adult female orangutan who
learned nearly 30 signs over a two year period. For his
dissertation study, Shapiro examined the factors
influencing sign learning by four juvenile orangutans over
a 15-month period.
The first orangutan language study program, directed by
Dr. Francine Neago, was listed by Encyclopedia Britannica
in 1988. The Orangutan language project at the Smithsonian
National Zoo in Washington, D.C., uses a computer system
originally developed at UCLA by Neago in conjunction with
IBM..
Zoo Atlanta has a touch screen computer where their two
Sumatran Orangutans play games. Scientists hope that the
data they collect from this will help researchers learn
about socializing patterns, such as whether they mimic
others or learn behavior from trial and error, and hope
the data can point to new conservation strategies.
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 copulating 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 even shown laughter-like vocalizations in
response to physical contact, such as wrestling, play
chasing, or tickling.
Species
* Genus Pongo
+ Bornean Orangutan (Pongo pygmaeus)
+ Pongo pygmaeus pygmaeus - northwest populations
+ Pongo pygmaeus morio - east populations
+ Pongo pygmaeus wurmbii - southwest populations
+ Sumatran Orangutan (P. abelii)
The populations on the two isolated islands were
classified as subspecies until recently, when they were
elevated to full specific level, and the three distinct
populations on Borneo were elevated to subspecies. Some
suggest that the subspecies wurmbii is conspecific with
the Sumatra population (P. abelii). In that case, the
resulting species, which would be distributed in Sumatra
and southwestern Borneo, would be known as Pongo wurmbii,
as that is the older name.[citation needed]
In addition, a fossil species, P. hooijeri, is known from
Vietnam, and multiple fossil subspecies have been
described from several parts of southeastern Asia. It is
unclear if these belong to P. pygmaeus or P. abeli or, in
fact, represent distinct species.
Conservation
status
The Bornean species of orangutans is highly
endangered,[18] and the Sumatran species is critically
endangered,[19] according to the IUCN Red List of mammals,
and both are listed on Appendix I of CITES. The Borneo
population is estimated at about 50,000 in the wild, while
the Sumatran species is estimated at 7000-7500
individuals. The orangutan is an official state animal of
Sabah in Malaysia.
Orangutan habitat destruction due to logging, mining and
forest fires has been increasing rapidly in the last
decade. A major factor in that period of time has been
the conversion of vast areas of tropical forest to oil
palm plantations, for the production of palm oil. Some UN
scientists believe that these plantations could lead to
the extinction of the species by the year 2012.
Much of this activity is illegal, occurring in national
parks that are officially off limits to loggers, miners
and plantation development. There is also
a major problem with the poaching of baby orangutans for
sale into the pet trade; the trappers usually kill the
mother to steal the baby.
Major conservation centres in Indonesia include those at
Tanjung Puting National Park in Central Kalimantan, Kutai
in East Kalimantan, Gunung Palung National Park in West
Kalimantan, and Bukit Lawang in the Gunung Leuser National
Park on the border of Aceh and North Sumatra. In Malaysia,
conservation areas include Semenggoh Wildlife Centre in
Sarawak and Matang Wildlife Centre also in Sarawak, and
the Sepilok Orang Utan Sanctuary near Sandakan in Sabah.
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