The Philippine tarsier (Carlito syrichta) is generally regarded as a small primate although there is some dispute about its true classification. They are closely related to the loris, lemur and bushbaby. There are several species of tarsier still existing. They are now found only in the islands of Southeast Asia. In 2008, the Siau Island tarsier was listed in the World's 25 Most Endangered Primates.

Its main claim to fame is its enormous eyes which are proportionately larger than those of any other animal. Its name comes from the tarsus (ankle) bones of the feet which are extremely elongated, resulting in very long hind limbs.

Range

The Philippine tarsier is endemic to the Philippine archipelago and found mainly in the south-eastern region. The islands of Bohol, Leyte, Mindanao and Samar all have populations of tarsier.

TarsierCredit: Wikimedia

Habitat

The tarsier prefers dense, low-level secondary forests. Perching areas are usually established about two metres above ground level. It is also found in primary tropical rainforest up to 700 metres above sea level. Areas of tall grasses, bushes and bamboo also offer it protection.

Description

While the head and body are between 10 and 15cm long, the hind limbs and feet are double this. The tail adds another 20 to 25cm. The fingers are also inordinately long with the third finger roughly equal to the length of the upper arm. While most of the digits have flattened nails, the second and third toes of the hind feet form grooming claws.

The Philippine tarsier is slightly heavier than the pygmy tarsier but still weighs only a maximum of 160 grams. It fits comfortably in a human's hand. Males weigh slightly less than females.

Each eyeball is as large as the brain and measures some 16mm in diameter. Like the owl, the eyes of the tarsier are fixed in the sockets so it must turn its head to alter the path of its vision. The head is round and can be rotated through 180 degrees. It has excellent night vision with the pupil filling almost the entire eye in dark light and shrinking to a thin line in bright light. The membranous ears are large and mobile, moving constantly.

The grey or dark brown fur is rough and sparse. The tail is narrow and bald apart from a tuft at the end. The underside has dermal ridges.

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Locomotion

The long legs allow the tarsier to jump three metres or more from tree to tree. Rounded pads on the digits give really effective grip. The tail is used for balance.

Habits

While the species are all nocturnal, some may be somewhat active during the daytime. They are extremely shy animals which sleep in dark hollows near tree trunks or shrubs in impenetrable vegetation. They may travel around one and a half kilometres across the forest when foraging. 

Tarsiers have several different calls including a loud piercing single note, a soft bird-like trill and a chirping like a locust. The male marks his territory with urine and the female marks her mate from a gland around the mouth.

Reproduction

The gestation period is about six months. Males insert a mating plug in the vagina of the female after mating. This gelatinous material hardens after being deposited and, while it can be expelled by the female, gives the sperm a time advantage in getting to an ovum.

Only one baby is born. They have fur when born and can climb within 24 hours. They are born with the eyes open. Infants may be carried in the mouth. The mothers have multiple breasts but only one pair contains milk. The others serve as 'handles' when the young are carried on the belly.

While foraging, the mother parks her baby nearby. By the end of the second year the young are sexually mature.  Some species live in small family groups while others are solitary.

Life expectancy is around 24 years in the wild but less than half this in captivity.

Tarsier2Credit: Wikimedia

Nutrition

The tarsier is entirely carnivorous and the only primate which is so. The dentition is unique in the primate world with the lower jaw having two rather than four incisors.

They mainly eat insects, particularly crickets and grasshoppers which they catch by jumping at them. They also eat bats, snakes, lizards and birds. On catching its prey, the tarsier uses the hands to take the insect to its mouth.

Threats

The live pet trade poses a grave danger to the tarsier. The practice of selling stuffed tarsiers to tourists has thankfully stopped. Feral cats prey on the tarsier and some are taken by owls and other large birds. Small carnivores which occupy the same habitat are also predators.

Although the tarsier was once reasonably common in the humid rainforests, their numbers have dwindled markedly as more and more of its habitat is cleared for farmland, housing estates and roads. Illegal logging, and slash and burn agriculture have a severe impact on this little creature. However indigenous tribes, especially in Sarangani province, believe the tarsier to be pets of forest spirits. To harm one brings bad luck on the perpetrator.

Conservation

Trading is now prohibited. Research is now controlled and any invasive techniques banned. Various initiatives have been implemented by the Philippine government is an effort to conserve the tarsier.

A sanctuary has been established on the island of Bohol. A large area is surrounded by a 7 foot high fence intended mainly to keep out predators such as feral cats. The tarsiers have become used to their spacious enclosure. However they climb the fence at night to forage further in the jungle. They then observe the curfew and return to the sanctuary before daybreak.

Tarsiers in Captivity

As stated, the life expectancy is dramatically curtailed in captive tarsiers. The lighting often causes permanent damage to the eyes. Sore eyes sometimes result from a poor diet. Their diet is difficult to replicate in captivity. Being in an enclosure and its associated activities causes stress to the tarsiers. They then tend to hit their heads which can cause fatal injuries as their skulls are very thin.