General Information Habitat Feeding and Breeding Conservation Interesting Facts Insight Bibliography

General Information

Belongs to a primitive order of Primates with it's own suborder called Tarsiidea, which is made up of one Genus: Tarsius. This genus is represented by five species - 1 species in Borneo (Tarsius bancanus), 1 in the Philippines (T. syrichta) and 3 in Indonesia (T. dianae, T. spectrum and T. pumilus).

The body size ranges from 8.5cm to 16cm and the tail is twice as long as the body. The spectral tarsier weighs between 80 to 165 g. Its lifespan in the wild is between 8 to 13.5 years.

 

Habitat

Fossils of the genus Tarsius have been found in Asia, Europe and America, although the group is now restricted to the Southeast Asian islands where they have lived for over 40 million years.

The spectral tarsier is endemic to the secondary lowland forests of the islands of Sulawesi, Great Sangihe, and Peleng. A basic group is made up of the mated pair (essentially monogamous) and their offspring. Territorial boundaries are marked with urine and a secretion from the scent gland on its chest, called the epigastric gland. Intricate songs are also used to defend its territory. In the morning, a whole family performs a territorial call and this is believed to be crucial to their breeding and survival.

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Feeding and Breeding

Its diet includes live insects , bats, snakes, birds and small mammals. It catches its prey by leaping at it, pinning it to the ground with its long fingers and killing it with a few bites. It eats almost all parts of its prey, even feathers, beaks and feet. Tarsiers eat up to 10% of their body weight each day and need to drink water several times each night by lapping it up from leaves or a pool or stream with its tongue.

The breeding season lasts the entire year. Females have multiple breast pairs, but only the pectoral pair is functional. The other breast pairs serve as anchoring points for new-borns. The gestation period is about 6 months and a single offspring, weighing less than 30g, is born. The offspring is well furred, has open eyes and is able to scramble around the branches but cannot leap until it is a month old. At 3 weeks old, the young begins to eat live food. While hunting, the female often 'parks' her young on a branch, communicating with soft clicks and whistles.

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Conservation

The spectral tarsier is abundant on the island of Sulawesi and is only endangered where the forest is being logged. Logging is responsible for killing tens of thousands of these creatures each year. The Nature Conservancy in Indonesia, together with the Indonesian Governement launched the Sulawesi Parks and Partnership Program, which focuses on community development, community awareness, environment education, and park management and enforcement to help conserve this species.

Because of their small size and adorable appearance, many people attempt to make pets out of these animals. However, they do not make suitable domestic pets because they are delicate and require live food. When kept as pets, these creatures often die in a matter of days. In captivity, the tarsier can become so extremely distressed that it may die of psychological trauma. In the Philippines, some captured tarsiers have been reported to commit suicide by smashing their heads against the bars of the cage. Another reason why it is not a good idea to keep T. spectrum as a pet is that all tarsiers which have been examined have been found to have some form of intestinal worms, such as hookworms and tapeworms, to which humans are susceptible.

Status: threatened species. CITES - Appendix II

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Interesting Facts

Special physical features
The eye orbit of the tarsier is larger than both its brain case and its stomach. Each eye has a postorbital plate behind it, which protects the eyeballs from being pressed against the powerful temporal muscles to their sides. The tarsier's eye structure clearly indicates that it had a diurnal ancestor; it has a focusing point in the retina known as a fovea, which is useful only in daylight. It also lacks a tapetum. Just before and during the killing strike, tarsiers shut their large eyes tightly to prevent injury to their eyes.

The tarsier has a point between its skull base and spine to allow its head to move 180 degrees to the left or right. Its upper lip lacks a cleft yet it has a musculature enabling it to make faces. It also lacks a dental comb, but is aberrant in lacking one set of lower incisor teeth. The ears, which usually turn towards the direction of the sound can be twisted, crinkled or moved in opposite directions .

Communication
Tarsiers have a wide range of calls; from a loud piercing single note to announce their whereabouts to a soft bird-like trill to a series of clicks. Females in oestrus make a special call. A mated pair also performs duets to strengthen their bonds, and their juvenile offspring may join in.

Sleep sites
Sleeping trees are central to the life of a tarsier and all tarsier territories contain at least one sleeping site. Bamboo thickets, vines tangles, and hollow trunks are used as sleeping sites but the most favoured spots are the intertwined roots of large strangler figs. After leaving a sleeping site, typically 10-20 minutes after sunset, the group spends a few minutes interacting before members leap off in different directions.

Defence strategy
They are prey to owls and wild cats. To startle predators, a tarsier will close its eyes when a predator comes near, then suddenly open its eyes and bare its sharp teeth to surprise the predator. It then has better chance to leap to safety. Snakes rarely eat sleeping tarsiers. It is suggested that they reduce their body temperature and thus become 'invisible' to snakes that hunt by sensing body heat. The spectral tarsier is considered to be a rather gentle creature, capable of displaying and having affection for both members of its own species. However, when the tarsier, especially the male, is frightened, it can be very aggressive and will react by biting.

Historical significance
In the past, tarsiers were used as a totem animal of the head-hunting Iban people of Borneo who believed that the animal's head was loose. Some natives would not refer to the tarsiers by name because they feared that if they did so then they would become possessed.

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Insight

The pair along the Leopard Trail are characteristically shy and elusive preferring to hide in the shadows of the trees. They are more often heard than seen. Their regular call is a single sharp high pitch chirp. To increase your chances of catching a glimpse of them, it is best to wait patiently and stay as quiet as possible. They become highly excited when they hear the Rangers' jingling keys.

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Bibliography

 

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