Tue, 06 Aug 2002

Unique tarsiers face threat from people's misperception

Myron Shekelle, Research Associate, Center for Biodiversity and Conservation Studies, University of Indonesia, Jakarta

Tarsiers are charismatic nocturnal primates. In Indonesia, they are found on Sulawesi, Borneo and Southern Sumatra as well as some other smaller islands. Most experts now consider any reports that tarsiers once existed on Java to be erroneous.

An adult male tarsier weighs about 125 grams and a female's weight averages about 90 percent that of males. Tarsiers have a tail that is about 25 centimeters long and their body is about half that length.

Tarsiers are exceptional in many ways. Their huge eyes are the largest of any mammal, relative to their body size. Pregnancy lasts six months -- an exceptionally long period for such a small animal, and the newborn tarsier may weigh 33 percent as much as its mother, also the largest for any mammal. That would be like a 50 kilogram woman giving birth to a 17 kg baby (imagine giving birth to a three-year-old human)! Once tarsiers are born they develop very quickly, however, and it is believed that they reach sexual maturity between 18 years and 24 years of age.

Tarsiers are arboreal, but they do not move through the trees like monkeys and squirrels, which run and climb with four legs quadrupedally. Tarsiers are known as vertical clingers and leapers, and this small animal that is about the size of a gerbil routinely makes leaps that are greater than three meters. To accomplish this, tarsiers evolved long legs that are twice as long as their arms and greatly extended ankle bones -- called tarsal bones (from which they get their name), which gives them an extra joint in their legs. This, in turn, gives them the ability to make powerful leaps.

With this ability for leaping, they propel themselves from sapling to sapling, almost as if they were flying through the understory of the forest. In fact, the first scientific study of tarsiers came in the late 1960s when an ornithologist working in Sarawak found his mist nets getting tangled up with tarsiers. Since then there have been many scientific studies of tarsiers in the wild that use mist nets to trap and survey wild tarsiers.

On Sulawesi, tarsiers are a major lure for adventure tourists who wish to see this beautiful and interesting animal in its natural setting at places like Tangkoko Nature Reserve in North Sulawesi and Lore Lindu National Park in Central Sulawesi.

Unfortunately, some people like to take these animals home as pets. Although tarsiers are protected under Indonesian and international law, they can often be found for sale in Jakarta at Pasar Pramuka and Blok M. In some places, such as parts of North Sulawesi, capture for the pet trade is thought to be a major threat to tarsier populations. This is doubly sad because tarsiers do not do well in captivity and even the finest zoos in America and Europe have failed to establish tarsier breeding colonies in captivity. Most captive tarsiers will die within a few weeks of being taken from the wild.

Another problem facing tarsiers is the misperception by farmers that tarsiers eat crops. This is a trend found throughout Sulawesi, with coconut farmers claiming that the tarsiers eat coconuts, chocolate farmers claiming they eat chocolate and corn farmers swearing that tarsiers eat corn.

Correcting this misperception has proven to be a challenge since indigenous people are more inclined to trust their folk beliefs than modern science. In fact, tarsiers are the only primate in the world that do not eat any vegetable matter. They are 100 percent faunivorous, eating only live-caught animals -- mostly insects like crickets and grasshoppers.

Conservation of wild tarsier populations is entirely consistent with local agricultural practices. In yet another sad irony for tarsier conservation, tarsiers should be good, if anything, for farmers because they eat crop pests, but farmers will sometimes eradicate them because of their false folk beliefs.

Tarsiers from Sulawesi are also interesting to scientists because it appears that they have speciated on Sulawesi.

Currently, scientists recognize five species from Sulawesi, including the Tarsius spectrum from near Makassar, South Sulawesi. The Tarsius dianae is from Lore Lindu National Park and other parts of Central Sulawesi, while T. pumilus is a pygmy form of tarsier from the mountaintops of the central part of Sulawesi. There are two species from offshore islands: T. sangirensis from Pulau Sangihe Besar, North Sulawesi and T. pelengensis from Peleng island, Central Sulawesi. Scientists have evidence that there may be 14 or more species of tarsiers on Sulawesi, but this theory needs verification, and they are studying DNA from wild tarsiers to test that idea.

Habitat loss is a major problem in Sulawesi, but tarsiers live in a broad variety of habitats and the tarsiers of Sulawesi, as a whole, are probably not in imminent danger of extinction.

Nevertheless, some populations are probably at risk and because some tarsier species have not even been identified yet, there is the sad possibility that some species could go extinct before they have even been named. One such possibility is in the Togian islands of Central Sulawesi. Scientists from Germany and the United States working with Indonesians have discovered that the Togian tarsiers are probably a new species, but habitat loss caused by logging is unchecked there and many species are threatened.

To lessen the risk that some tarsier species go extinct, scientists and conservationists from Indonesia and abroad are working hard to overcome the misperceptions -- some of which are repeated in the mass media -- that threaten tarsiers. First, tarsiers do not make good pets. They are very cute, but they have a vicious bite, do not like to be handled and do not live very long in captivity. Second, tarsiers do very well in kebun (plantation) habitats if they are left alone. They may even help farmers control insect pests and they certainly will not eat farm crops.

Since tarsiers do not keep well in zoos, one of the very few places in the world where they are on public display is at Taman Safari park in Cisarua, Bogor, about an hour's drive from Jakarta.

Like in the movie Gremlins, tarsiers are photogenic animals that are sometimes in demand as pets, but they have the sharp teeth of a meat eater and can deliver a vicious bite.