Philippine Tarsier

## Description

Known as the “world’s smallest monkey” because of its similarity in appearance to that primate, tarsiers, along with lemurs, tree shrews, and lorises, actually are members of a more primitive suborder of Prosimii or prosimian. They are amongst the oldest land species that have existed continuously in the Philippines, dating from the early Eocene period, 45 million years ago. The Philippine tarsier has various distinctive habits and characteristics that make it an object of both popular curiosity and scientific research. Its eyes are unique and are almost twice as big as those of humans, however, they cannot see from the corners. Its head can rotate as much as 180 degrees, so it is able to leap backward with great precision. In addition, enabled by adhesive discs on the soles of its limbs, tarsiers cling to branches either horizontally or vertically.

## Distribution

This species is native to the Philippines, where it lives on the islands of Leyte, Samar, Dinagat, Siargao, Bohol, Mindanao, Basilan and Maripipi. Philippine tarsiers inhabit areas of tall grasses, bamboo shoots, small trees, and bushes in tropical rainforests. They prefer the jungle canopy and leap from limb to limb.

## Behavior

Philippine tarsiers are nocturnal but are also active at dawn and dusk. During the day they sleep in dense vegetation or sometimes in a hollow tree. At sunset, they begin searching for insect prey. They are agile acrobats, easily leaping vertically from tree to tree. Philippine tarsiers are solitary but may sometimes associate in groups of four animals or fewer. They demonstrate little fear of other species and especially humans unless a quick movement is made. When they are threatened they make a high-pitched squeak. Although less vocal than other primates, a tarsier uses a variety of means of communication, including calls for territorial maintenance and the spacing of males and females. They also use scent marks from glandular secretions to delineate their territories.

## Diet

Philippine tarsiers are carnivores (insectivores). They mainly consume insects but will also eat spiders, lizards, birds, and other small vertebrates.

## Reproduction

Philippine tarsiers are monogamous, which means that one male mates with one female exclusively. They tend to breed at any time of the year. A single baby is born following a gestation period of about six months. A baby tarsier is very well developed when born, with a full covering of fur and open eyes, and after just one day it is able to climb. As a mother climbs around the trees, her young will cling to her belly or is carried in her mouth. When 42-60 days old, Philippine tarsiers start to hunt their own insects, and soon after, they are weaned. They usually reach sexual maturity between the age of one and two years.

## Population

### Threats

Tarsiers are under severe threat by trappers and hunters, who shake them out of the trees or chop off the branches of trees where they live. They are also popular as pets, especially in Mexico. However, tarsiers do not often live long in captivity, as being captured traumatizes them so much that they will beat their head against the cage, to the point of killing themselves. These animals are also significantly affected by the increasing deforestation of their native habitat.

### Number

According Primate GCAP Report the total population size of the Philippine tarsier is less than 2,500 individuals, including 700 tarsiers in Bohol’s Forest. Currently, this species is classified on the IUCN Red List as near threatened (NT) and its numbers continue to decrease.

### Ecological niche

Being predators, Philippine tarsiers may help to structure insect communities. To the extent that they are preyed upon by other animals, they may impact predator populations.

## Fun Facts

The Philippine tarsier is known to the native people as “mamag”, “magau”, “mago”, and “magatilok-iok”.

During its waking hours, the thin ears of the Philippine tarsier are almost constantly being crinkled or furled.

The eyes of a tarsier are 0.63 in (16 mm) in diameter and each of their eyes is heavier than its brain. They have the biggest eyes relative to the body size of any mammal. If human eyes were of equal relative size, they would be as big as grapefruits.

Tarsiers hunt their prey by jumping from branch to branch. They can leap up to 16.4 feet. When seizing its prey, the tarsier will carry it in its mouth.

Tarsiers have the unique ability to rotate their heads for 180 degrees while their body remains still. This enables them to remain "silent" while awaiting their prey.

Philippine tarsiers can hear frequencies up to 91 kHz. They can make vocalizations of a dominant frequency of 70 kHz.