Primates of Asia & Indonesia
Together, the land mass of Asia and the islands of Indonesia make up a true a primate haven, serving as homeland to over 180 different primate species. That might not be too surprising to you if you already know that Asia is the world’s largest continent, forming almost 1/3 of the Earth’s total area of land.
Conservation Alert! Asia has the highest number of threatened primate species, with 40% of them in danger of becoming extinct. Just as troubling is the fact that 10 out of the 25 most endangered primates in the entire world reside in Asia and Indonesia. These statistics are harsh truths primarily because of the negative environmental impact caused by the human primate population in Asia, which now totals over four billion and rising. As stated by the Association for Tropical Biology and Conservation, “Asia has the highest deforestation rate of any major tropical region in the world and is also being massively altered by rampant industrial logging, plantation expansion, overhunting, the illegal trade in wildlife and wildlife products, pollution and degradation of freshwater and coastal marine ecosystems, rapid human population growth, and other threats.”
YOU CAN ACT NOW: We must immediately come together in support of worthwhile ventures such as petitioning Asian governments for the expansion of protected national parks in Asia and by providing financial support to projects that promote conservation, field research, and education of the human residents who share their space with our nonhuman primate friends. Visit our favorite Conservation Agencies to learn more about the specific projects you can feel confident supporting.
Primate Groups of Asia and Indonesia
There are 3 species of Asian prosimians: the Slender Loris, the Slow Loris, and the Pygmy Loris. Lorises do not have a tail to speak of, and they are characterized by their large, round eyes that are used for night vision, given that they are most active after dark. However, even at their “most active,” lorises are slow-moving, using all four limbs to almost painstakingly crawl across branches of the trees, searching for insects, small vertebrate animals, and tree gums to eat. As it turns out, the names are descriptive of their features. The slender loris is, hmm…skinny. The pygmy loris is, er…small. And, the slow loris is, well…really unhurried, and darn cute at that!
Fun Fact: The appendages of a slow loris are different from many other primates. The thumb and big toe stick out sideways, like an overzealous hitchhiker! This arrangement is perfect for their locomotion style, which consists of grasping and hanging from branches, with thumbs and toes perfectly positioned to hang on pretty much indefinitely.
Tarsiers dwell on the islands of Southeast Asia and nowhere else. And talk about a clique! These tiny snobs of the Primate Order just won’t fit neatly into groups with prosimians, monkeys, or apes. A confusing suite of features causes scientists to disagree on tarsier classification, and these little primates are sometimes named as prosimians and sometimes referred to as monkeys. Now, most studies are leaning towards placing tarsiers in a similar grouping as monkeys, (Haplorrhini), but keeping them somewhat distinct from all other primates since the tarsier’s set of features is different enough to relegate them to their own grouping. There are about six or seven species of tarsiers, depending on how they are classified, and all are facing population losses as more and more habitat disappears each day. (Click here for a listing of five of the most common tarsiers.)
What IS that thing, anyway? Tarsiers are difficult to encounter, as they are small (4-5 oz), somewhat elusive, and strange when it comes to other primates. But, when you do find one, don’t freak out!! The tarsier’s unusual appearance primarily has to do with their nocturnality (getting their jollies at night and sleeping all day). To help navigate in the dark, tarsiers have very large eyes that really are bigger than their stomachs! Their eyes do not have a tapetum (reflective layer of cells that most nocturnal animals have), but the tarsier’s eyesight is enhanced by the ability to turn its head around 180 degrees in each direction, like an owl (or a possessed Linda Blair). Their heads are sandwiched between Dumbo-like ears that can pick up sound like no one’s business but can also be folded down when necessary for protection. Another fascinating feature possessed by tarsiers is their suction-cup fingertips, resembling the foot pads of frogs. These specialized fingers are great for clinging onto slippery branches as the carnivorous tarsiers hop around, looking for tasty insects, birds, bats, and even small snakes to eat. Tarsiers are very cool little, um…
Monkeys in Asia are considered to be “Old World Monkeys,” meaning they originated in Africa and later spread out into Europe and Asia. Like other Old World Monkeys, Asian monkeys share several things in common, such as:
- sharp, pointy teeth that help to break down crunchy plant matter that they eat
- a large stomach with many pouches that house an abundance of bacteria to further help digest plant material
- ischial tuberosities. “Ok, hold on. I-sh-ee-ul what?” Ischial tuberosities! Look at these monkeys’ rear ends. You will see two calloused areas filled with fat on their rump. These fat pads let them sit on branches all day without a care in the world and without worry of tumbling off when they snooze. Talk about ergonomic!
- long tails for balance while moving along branches and long legs for leaping from tree to tree
- missing thumbs…it’s true! Many Asian monkeys have very short thumbs. If you’re wondering where Thumbkin went, he took a hike so that these primates could form strong, hooking grips on branches as they hang and so there aren’t any obstructions as they swing from tree to tree.
- diurnal behavior, meaning that they are active during the day and sleep at night
There are several types of monkeys that live from India throughout all East Asia and southward to Indonesia. One of the largest groupings of Asian monkeys is the Colobine monkeys, named from the Greek word kolobus referring to their “mutilated” or tiny thumbs. Asian Colobine monkeys include proboscis monkeys (very well-endowed snouts), snub-nosed monkeys (little up-turned noses), leaf-monkeys (vegetarians for life!), pig-tailed monkeys (tiny bare-skinned tails), and langurs (long and lean and topped with some very unique hairstyles).
Macaques are another type of monkey found primarily in Asia. They tend to have a more variable diet than the Colobines (that eat mostly leaves), and so macaques enjoy a variety of fruits, nuts, vegetables, and even occasional eggs and insects. Macaques tend to live in large troops ranging from 20 to hundreds of individuals. These monkeys may be familiar to you as they have been widely studied, both in natural settings and for medical and laboratory research. Have you ever seen a red-faced monkey sitting in a hot spring or playing with a snowball? This is a Japanese macaque (Macaca fuscata). Ever seen a black monkey with a huge, white mane and tail with a tiny black tuft? This is a lion-tailed macaque (Macaca silenus). Ever heard of the Rh factor in your blood, as in are you positive or negative? The Rh factor was named for its discovery in the Rhesus macaque (Macaca mulatta), a monkey used for many years in medical research. There are 19 recognized living species of macaques, 18 of which are spread throughout Asia.
At first glance, some of Asia’s apes may appear as monkeys. However, a closer look reveals some very important differences that make these primates unique. Lesser apes, as they are known, include siamang, concolor gibbons, hoolock gibbons, and six other gibbon species. These apes resemble many monkeys in that they are of medium body size with long arms and legs, ischial callosities, and reduced thumbs. But, they are not monkey-like when it comes to their mental capacity since they have larger brains relative to their body size than most monkeys do. Some other differences are that they have distinctly shaped back teeth, broad chests, wide toes and they never have a tail! They are truly adapted for brachiating, or moving arm-over-arm in the trees, rarely descending to the ground but instead suspending effortlessly as they feed and socialize. Social interactions include duetting, or loud, synchronized vocalizations that are used to define the territories fiercely defended by male and female pairs. Gibbons and siamangs live in small families with a mama and a papa and up to four babies that stay with their parents until they are old enough to find mates of their own (about 10 years of age), upon which times the parents will harass them until they leave. (Sound familiar to anyone with a grown man still wearing Superman skivvies and living in the basement??) Gibbons are spread out all through Southeast Asia and Indonesia, and siamangs are found in Malaysia, Thailand, and Sumatra.
Asia is also home to some very special great apes, the orangutans, or “men of the forest.” Like the lesser apes, orangutans are adapted for living in trees, as evident by their long arms, reduced thumbs, and relatively short legs. In fact, they are the world’s largest living arboreal (tree-dwelling) mammal. Although they can move quickly through the trees when necessary, orangutans are much heavier than lesser apes, and their movement in the trees tends to be restricted to climbing with the hands and feet as opposed to true brachiation. Males spend a good deal of time traveling on the ground, and to do this, they make fists with their hand and walk on all fours. Being classified as great apes, this means that orangutans are bigger and have wider canine teeth, pelvises, and lower leg bones than are found in lesser apes. If you ever find yourself in Borneo or Sumatra, you can easily identify an orangutan by its reddish brown coloration, bare face, and long, shaggy coat. You won’t likely see large troops of orangutans since they are relative loners compared to the majority of socialites in the primate world. Females and their youngsters stick together while traveling in search of food and nesting sites, and males travel alone, ambling over far distances to find food and potential mates. Orangutan solidarity is not necessarily by choice, since orangs are actually quite gregarious when they do occasionally congregate. Large groups, however, only form under unique conditions when there are several huge trees producing mass quantities of fruit that can support more than a few individuals at a time. For the majority of the season, orangs must travel long distances to find enough food to support their large bodies, and more is not merrier when it comes to sharing limited resources. How large are these guys and gals? Adult females weigh around 80 pounds, but males tip the scales at almost 200 pounds!
Sumatran versus Bornean Orangutans…what’s the difference? The main difference is location, location, location. The Bornean Orangutan (Pongo pygmaeus pygmaeus) is confined to Borneo and the Sumatran Orangutan (Pongo pygmaeus abelii) is found only on the island of Sumatra. Bornean orangs have thick, dark hair and dark faces. When male Bornean orangs mature into adults, they develop big cheek pads and throat pouches that are used to make loud calls that can be heard for half a mile! Sumatran orangs also have cheek pads and throat pouches, but they are not quite as large. Sumatran orangutans are further distinguished from the Bornean subspecies because they tend to be lighter in color and thinner overall with a longer face.
Given the shear expanse of Asia, it is difficult to describe in a few short paragraphs the many different cultures that can be found throughout the continent. Asia can be split up into several geographic subdivisions: Russian controlled Siberia in the north; the Asian countries of China, Japan, and Korea in the East; the islands of Indonesia, Borneo, and others in the Southeast; India, Pakistan, and Afghanistan in the South; and the group of nations collectively known as the Middle East in West Asia. A variety of religious and cultural traditions exist in Asia, and the main means of subsistence range from nomadic hunting to farming to industrialization and technological innovation. Several groups of people in Asia have special places in their hearts for nonhuman primates. For example, the Chinese zodiac (read about its origin here) runs on 12 year cycles, with each cycle lasting for one year. Each cycle is assigned an animal name, including the 9th annual cycle, the Monkey, which includes anyone born in 1920, 1932, 1944, 1956, 1968, 1980, 1992, or 2004. People born during the monkey’s year are said to be inventive, witty, popular, good-humored, and versatile! In Indian culture, Hanuman langurs (Semnopithecus enteullus) are highly revered, getting their name from the Hindu god “Hanuman” who was renowned for his courage, power, and selfless service. The monkeys are generally seen as sacred in India, and thus they have free reign in towns and villages, entering people’s homes at will to get food from the table and walking through the streets without a care.
Many of the earliest primate fossils found to date in Asia represent members of the Adapine grouping of primates that were alive in Europe and Asia during the Eocene. These small animals were primitive compared to the primates currently living in Asia, and were most likely slow-moving, grasping primates similar to living lorises. Another grouping of Eocene primates was also present in Asia during the Eocene, the Cercamoniines. Now, don’t worry too much about pronouncing that name, in fact, let’s shorten it to Cercs for the time being.You might recognize this little Cerc to the left, dubbed, “Ida,” and which caused quite a stir in the news in recent years.
The Cercs were closely related to the Notharctines (let’s call them the Noths) that are known to have lived primarily in North America. Like the Noths, the Cercs were a successful group of primates that were well adapted to their habitat. However, the Cercs were more diverse in size and appearance than were the Noths. Cercs ranged from tiny mouse-sized, insect-eating primates to larger cat-sized, fruit-eaters. Cercs have been found in several parts of Asia, including Pakistan, China, and Burma.
In addition, a few tarsier-like primates known as Omomyoids have also been discovered in Asia, appearing early in the Eocene, and being characterized by flat faces and large eyes with skeletal adaptations for leaping. The Omomyoids were similar to living tarsiers, but there have been other fossil finds from the same time period that are practically identical to the tarsiers we now see, so it is unclear as to how the Omomyoids are related to living primates.
Other fossils from various primitive, but more monkey-like animals have also been discovered in southern China, Burma, and Thailand. These early primates were small to mid-sized and most likely fruit-eaters well adapted to their arboreal (tree-dwelling) lifestyles. It will be interesting to see how the stories of the Eocene primates unfold as scientists continue to make unearth new fossils from this time period.
Another interesting fossil from a later time in India is known as Sivaladapis nagrii. This primate was alive and well during the Miocene Epoch (~25 million years ago) and resembled modern-day lemurs, though missing some key features such as a toothcomb. Present in the Asian fossil record as well are other primates from the Miocene, including many specimens of fossilized loris that represent (yo, holla back!) the species Nycticeboies simpsoni. As mentioned in the North America section, the Miocene was the Age of the Apes, and several fossilized remains from ape species such as Pliopithecus, siamang-like apes found in Europe and Asia, Dionysopithecus, a small gibbon-like ape in China, Laccopithecus, a large gibbon-like ape, and Sivapithecus, an orangutan-like ape from northern India and Pakistan.
LOOK UP! Giant ape ahead!!! Gigantopithecus was the largest primate we have discovered to date, and this animal wasn’t playing around when it came to its giganto-size. An enormous mandible discovered in China suggests that this primate would have weighed 900 pounds or more!!! The teeth that have been discovered so far are also very large and flat, which suggests that Gigantopithecus would have been eating lots of fibrous plant matter, with heavy emphasis on the word LOTS.
Click here for an image of a reconstruction of Gigantopithecus made by Russell Ciochon and Bill Munns.
Thinking that could be Bigfoot” are you??? You’re not alone. Check out our Cryptoprimatology Blogs for more about what some folks believe to be evidence of living giant apes.