The International Union for Conservation of Nature’s Red List of Threatened Species (IUCN) has ranked the pygmy tarsiers from the mountains of the Sulawesi Island, Indonesia, as endangered, and their adult numbers are decreasing due to continued human intrusion into their habitat. The IUCN ranking was made in the year 2020.
The pygmy tarsier was considered to be extinct for 80 years, since 1920. In the year 2000 Indonesian scientists discovered a dead pygmy tarsier in one of its rat traps. Eight years later, primate ecologist Sharon Gursky, a professor at Texas A&M University, climbed the Sulawesi island mountains with a team of scientists on a mission: to prove that the pygmy tarsier is extinct.
They waited for three months, 60 days of which were spent setting up mist nets commonly used to capture animals. The work was not easy. Pygmy tarsiers are nocturnal, and once it’s caught in the net, it has to be gently detached so it won’t get hurt.
The nets caught birds and 100 spectral tarsiers. The pygmy tarsiers were caught on August 29, 2008 — two males and one female — and a fourth pygmy tarsier escaped.
Gursky tried to put a radio lock on one of the tarsiers. These animals have huge eyes, too big to move their eyeballs. Instead, the head must make a 180-degree turn left and right to see either side. As Gursky struggled with the neck lock, the tarsier bit her finger.
Tarsiers are estimated to have been in the world for 45 million years.
Last year, 2020, the IUCN report said no research or monitoring of these animals is being done, and there is no known protection of their entire specific habitat. Some pygmy tarsiers were seen in Lore Lindu National Park, a protected area, and in Mount Rantemario.
The Tarsius pumilus (its scientific name) is protected through international legislation, and trade controls, intended to protect the animal from being traded as pets or sold for consumption or other reasons to take it away from its habitat.
The pygmy tarsier is considered endangered because of its small area of occupation — 175 square kilometers, equal in size to three-tenths of Metro Manila, or is almost the same size as Washington D.C.
The human invasion
As the human population grows, people have encroached on the montane forest areas that these pygmy tarsiers call home. They inhabit the montane forests and destroy trees that pygmy tarsiers inhabit, especially in South Sulawesi, where human population is concentrated. As their population grows, it is forecast by the IUCN that people will expand their territory, encroaching further on the forests of Central Sulawesi.
Trees are the tarsier’s daytime home. They cling to their tree in sleep, or crawl inside a tree trunk hollow. Pygmy tarsiers like nestling in large trees. They don’t make nests.
Pygmy tarsiers are also collateral damage in conflict zones, especially in Central Sulawesi. Factional fighting caused the dislocation of people who were resettled in refugee camps, including one camp situated en route to Rorekatimbu.
Finally, there have been ecosystem stresses. Former habitats, with the coming of humans, have been converted to grow agricultural crops. The use of pesticides also affects the animal’s feeding grounds. The growth of non-timber crops and changes brought about by small-holder farmers have also affected the quality of the habitat of pygmy tarsiers.
How they were discovered
When Gursky climbed the Indonesian mountains of central Sulawesi Island in 2008, she was on a mission to prove that pygmy tarsiers are extinct. She and her team set up 60 mist nets over a period of three months. The nets caught birds and 100 spectral tarsiers. Then on August 29 of that year, four pygmy tarsiers were seen on the net, but one of them escaped. That left them with two males and one female pygmy tarsier.
The pygmy tarsier always looks like it’s smiling, but don’t be fooled. One of them bit Gursky’s finger while she attached a radio lock to its neck. The radio collar minimizes impact on an animal’s behavior, while maximizing the scientist’s ability to track them.
Pygmy tarsiers vs. other tarsier species
Pygmy tarsiers were once considered to fall within the species of the spectral tarsier, but some observations showed that the two are very different, and out of 18 species and subspecies, the pygmy tarsier is unique in its own way. For example:
- Pygmy tarsiers are less than half the size of other tarsiers. They weigh two ounces on average, and are the size of a mouse.
- Unlike other tarsiers, pygmy tarsiers have hair on their ears, head, and body, but not on their tail.
- Claws. They are the only tarsiers with claws that enable them to hang onto trees that are covered with slippery moss. All other tarsiers have nails.
- High pitch. Pygmy tarsiers regularly communicate at a vocally higher frequency than other tarsiers do within the same context, and they do so less frequently.
- Scent? It is not known whether they use scent markings, which haven’t been spotted. It may be because their scent markings are washed away with the rain. Other tarsiers regularly communicate by scent markers.
- Cool and mossy. Pygmy tarsiers, unlike all other tarsiers, live in the cool mountaintops of Indonesia, and can cling to mossy tree branches with ease. All the other species are lowland tarsiers that prevail in the forest where the climate is hot and tree trunks and branches are dry.
- Introvert? Pygmy tarsiers don’t communicate as frequently as other tarsiers, although they do make duet song vocalizations. Because of the high frequency of their voice, humans can’t hear what they’re saying, although Gursky has seen their mouths moving as if in conversation or song.
How was the pygmy tarsier believed to be extinct?
It’s very possible that the private nature of these tiny primates enabled it to go undetected for 80 years. Other reasons they successfully hid from humanity for so long could be:
- They can’t be heard. They make sounds that don’t fall within the frequency that can be heard by human ears.
- They are hard to see. They were only seen when they were captured by a mist net.
- They live in remote areas. Gursky found the three tarsiers high in the Sulawesi mountain, 6,900 ft. above ground, where the weather is very cold.
- They live in montane forests. These forests are harder to navigate because they grow on the mountain’s slope. This is why so far only small-scale human expansion has taken place. But as the human population grows, further encroachment on the pygmy tarsier’s territory puts them these animals at further risk.
Decreasing in number
The IUCN listed the pygmy tarsier as decreasing in number, and added that this animal is “data deficient”. Knowledge is based on a few museum specimens and the three live tarsiers that were found by Gursky. Another obstacle to studying pygmy tarsiers is their habitats, which are disorganized and fragmented.
What if there were no pygmy tarsiers?
Pygmy tarsiers play a role in the food chain. They feast on insects, spiders, and lizards. They also host bedbugs, lice, fleas, roundworms, tapeworms, etc. They are eaten by wild cats, snakes, and birds such as hawks, eagles, and falcons. These tiny tarsiers do an awful lot of good in distracting bugs from people. And they keep the earth balanced. Their decreasing population will affect the ecosystems that interact with them. And even though those three pygmy tarsiers found by Gursky in 2008 may not be around anymore, we must bear in mind that it’s not just a matter of one small group of creatures that are lost, but more a matter of yet another small group of creatures, one after the other. Because one day, extinctions will accumulate so much that we will reach the point that we can’t help but find ourselves living with the consequences.