Who says the Philippine tarsiers are on the verge of extinction?
By Henrylito D. Tacio
Photos courtesy of Simeon Gabriel F. Bejar and Paolo Lim
The Philippine tarsier, characterized by its large eyes, elongated tail, and distinctive hands and feet, likely served as an inspiration for Steven Spielberg’s creation of E.T., The Extra Terrestrial (1982).
That alone is one reason why Philippine tarsiers should be given importance. But “putting a value on how important Philippine tarsiers are can be complicated,” said Simeon Gabriel F. Bejar, who first got involved with Philippine tarsiers when he was still taking BS Biology from the Institute of Biology at the University of the Philippines Diliman.
“When we look at their role in ecosystems, Philippine tarsiers contribute to controlling insect populations, given that they are predominantly insectivorous,” he continued. “Their presence in forests may also influence populations of their predators, which may include snakes and raptors.
From a more human-centered perspective, Philippine tarsiers are regarded as flagship species, which enhances their cultural significance, particularly as they serve as icons in popular culture (for instance, their depiction on the 200-peso bill) and their strong associations with ecotourism.
“Their designation as a flagship species, which primarily stems from their charismatic appearance, also makes them relevant in conservation, especially as umbrella species – being a flagship species makes it easier to fund conservation projects aimed toward protecting them and safeguarding these species inherently contributes to the preservation of their habitats and the biodiversity they support,” Bejar said.
The Philippine tarsier has become a symbol of Bohol; however, only a limited number of individuals have had the chance to experience a close interaction with it. The heightened concern surrounding tarsiers can be attributed to their precarious status, similar to that of the Philippine eagle, as they are nearing extinction.
Endangered primates
The Switzerland-based International Union for Conservation of Nature (IUCN) has classified the Philippine tarsier as “one of the most endangered primates” from 2014 to 2016. “Many populations of Philippine tarsiers have already been locally extirpated and of those that remain some surely are at imminent risk of extinction,” said the report.
The UN Convention on International Trade of Endangered Species of Wild Fauna and Flora (CITES) listed the Philippine tarsier under Appendix II, which means trade of the species and subspecies “is strictly regulated.”
In 1997, then President Fidel V. Ramos signed Proclamation No. 1030 declaring the Philippine tarsier as “a specially protected faunal species of the Philippines.” As such, “the hunting, killing, wounding, taking away or possession of the Philippine tarsier” and activities that would destroy its habitats are strictly prohibited.
Natural habitat
The Philippine tarsier (scientific name: Carlito syrichta, formerly Tarsius syrichta) is a species native to the Philippines, inhabiting several regions such as Bohol, Samar, Leyte, and Mindanao. This primate favors dense forest environments; however, it also lives in abandoned clearings that feature new growth of medium-height vegetation, found in both lowland and mid-elevation areas.
“The Philippine tarsier is found in various habitats, particularly in dense patches of bushes, tall grasses, bamboos, and small trees in tropical rainforest,” informed Dr. Corazon Catibog-Sinha, then the PAWB assistant director when interviewed by this author. “It is also found in abandoned clearings with new growths of medium-height plants, both in the lowlands and at medium elevations.”
In the past, the Philippine tarsiers used to be common in coastal forest near rivers and creeks. They have also been sighted at the base of the tree trunks and roots of bamboo but rarely in cavities at the tree tops. They prefer the jungle understory and leap from limb to limb.
On why tarsiers are vulnerable species, Bejar contends, “Tarsiers are small and can only do so much. Unlike birds and bats who fly, tarsiers can mostly only leap, which makes them more vulnerable to forest fragmentation, and so even a single highway between forests can already effectively isolate tarsiers from crossing.”
Why they’re vulnerable
Bejar cited the tarsier population they studied in Initao-Libertad Protected Landscape and Seascape in western Misamis Oriental. “They were not able to cross the tourism zone and the special protection zone because of the highway that bisects the protected area,” he said.
“Their small size also made them vulnerable to many predators, including domestic cats and dogs. Unfortunately, tarsiers falling victim to these animals has become a common occurrence as people begin encroaching forests to build their homes or to convert to farms.”
The increasing popularity of tarsiers has also rendered them vulnerable to illegal hunting and poaching activities. A recent study conducted in Bohol has highlighted tourism as a significant threat to these creatures, as they are often hunted to draw in visitors or kept as pets for exhibition purposes.
“I personally think tourism can be used in favor of conservation, but the current ecotourism models need to be changed, as there are better ways to showcase tarsiers without causing them stress,” said Bejar, now a full-time PhD biology student in the same UP institute and a part-time consultant for a few wildlife-related projects.
He believes that significant misinformation and misconceptions regarding tarsiers are being propagated through ecotourism, potentially intensifying interactions between humans and tarsiers. He cited the notion that tarsiers engage in self-destructive behavior when under stress is not a natural occurrence.
“Tarsiers have many options to mitigate stress when out in the wild: they can move far away from disturbances, they can hide from predators, they can huddle or seek shelter when the weather is bad,” Bejar said.
It’s a different story in captive settings. “Circumstances are different, and they may not have ways to protect themselves,” he said. “If tarsiers, as they say, are committing suicide, then the problem might lie with their facilities. Instead, the behaviors are simply attributed to the tarsiers being sensitive to stress. Extreme stress and suboptimal living conditions may cause this ‘suicidal behavior,’ which is why it is important that captive facilities still take accountability for such events.”
Other reasons
There are several other reasons why Philippine tarsiers are a threatened species. “They are not necessarily on the verge of extinction, but they are heavily threatened by habitat destruction and alteration, forest fragmentation and illegal poaching/hunting,” Bejar said.
A genetic study about a decade ago revealed that certain island populations of tarsiers represent distinct lineages, particularly the Bohol-Samar-Leyte lineage, the Dinagat-Caraga lineage, and the Mindanao lineage.
“While we are still working on resolving the taxonomy of Philippine tarsiers based on this, it is possible that these lineages could represent different species altogether,” Bejar said. “Now, if we consider this, and the fact that tarsiers face a lot of other threats that can be specific to certain regions or islands, then it is possible that some lineages might actually be more threatened than others.”
He cited the Philippine tarsiers living in Dinagat Island, which was previously part of Surigao del Norte. “They are under severe pressure from island-wide mining operations, which may not be the case for tarsiers in larger islands like Mindanao,” Bejar explained.
“Unfortunately, some of the other threats are still unaccounted for, and, considering that there are very few people who study tarsiers, identifying, addressing, and mitigating threats have become challenging,” Bejar said.
Huge eyes
The Philippine tarsier stands only about 5 inches tall (small enough to fit snugly in the human hand). However, it has eyes measuring 16 millimeters and each eye weighs more than their body size, according to the website, animalia.bio. Among mammals, tarsiers possess the largest eyes in proportion to their body size.
Another remarkable feature is its exceptional ability to detect prey and maneuver through the trees. Prior to leaping from one branch to another, it swiftly rotates its head to identify its target destination and then executes a rapid backward jump toward that location.
An intriguing aspect of this primate is its classification as a nocturnal hunter, as it typically rests during daylight hours and becomes active at dusk. Tarsiers are adept at pursuing insects, lizards, and small amphibians during the night. Their primary tools for hunting are their oversized eyes, each of which surpasses the size of their entire brain.
A Philippine tarsier has the potential to live for as long as 24 years in its natural habitat, while its life expectancy in captivity typically exceeds 12 years. However, many tarsiers that are taken from the wild and kept in captivity often survive for only two to five years.
Conservation efforts
Conservation efforts for this species began in 1988 with a study focused on the habitat needs of tarsiers in Bohol. This was succeeded by a project led by the environmental department of Region VII, which ran from 1991 to 1992 as part of the Debt-for-Nature Swap initiative.
“The Philippine tarsier poses challenges for captivity due to its unique dietary and habitat needs,” said the BMB. “Tarsiers in captivity typically have a short lifespan, and most offspring born to captive tarsiers fail to reach maturity. They are sensitive and fragile creatures that do not tolerate frequent handling or interaction well.”
Bejar believes that the most effective means of saving Philippine tarsiers is to enhance our understanding of them. “As a scientist, I suggest studying more about their ecology and their behavior in different islands and in different habitats,” he said.
“As Filipino citizens, considering that the Philippine tarsier is one of the more popular Filipino icons, we should do our best to try to learn more about them, so that in cases when we encounter one, we know what to do,” he added.
If they are in the forest, for instance, it is advisable to leave them undisturbed and allow them their space. “If you see them in your farm, and if you don’t know what to do, contact local experts or contact local authorities before attempting to capture them,” Bejar suggested.
Attempting to rescue tarsiers from farms might be more harmful, since those farms might actually be part of their homes. “They might even be helping control insect pest populations there, we just don’t know. Which is why we need more studies about why we see them in farms,” he said.
Bejar also suggested not to visit those areas (tourism spots, that is) that do not treat these animals properly. “If you ever go to one, avoid handling and stressing them out,” he pointed out. “We can also help by supporting the initiatives or projects of conservation and research organizations and institutions that aim to further our understanding of tarsiers, and biodiversity in general, through even the simple act of sharing and spreading the word.”– ###
