Tarsius tarsier is found on the islands of Sulawesi, Great Sangihe, and Peleng, in the Indonesian archipelago (Macdonald, 1987).

Biogeographic Regions: oriental (Native )

Other Geographic Terms: island endemic

Tarsius tarsier is one of the smallest of the primates. Its short body and round head are covered with a soft, velvety coat which is gray to gray-buff in color. Its tail is long, slender, and covered in scales like those which are found on the tails of rats and mice. It has a long and bushy tail tuft at the end.

Tarsius tarsier has a head-body length of 9.5 to 11 cm, and a tail length ranging from 20 to 26 cm. There is little difference in size between the males and females of the species. The head and body length together is only half as long as the entire hind limb (including the thigh, lower leg, and foot, all of which are greatly elongated and about equal in length to one another). The tibia and fibula of this animal are fused together in the lower portion to act as a shock absorber when the animal leaps from tree to tree.

The fingers and toes of T. tarsier are very long and slender in order to allow the animal to cling to trees and branches. Its second and third toes have a special toilet claw which it uses for grooming. The other toes and fingers all have nails.

The most characteristic feature is of T. tarsier is its enormous round eyes. In fact, the eye orbit of this animal is larger than both its brain case and its stomach. Each eye has a postorbital plate behind it, which protects the eyeballs from the powerful temporal muscles to their sides. The ears are very large and mobile. The large teeth are needle sharp.

(Macdonald, 1987; Kavanagh, 1983; Schultz, 1969;   http://www.snowcrest.net/goehring/a2/primates/tarsier.htm)

Range mass: 80 to 165 g.

Range length: 9.5 to 11 cm.

Sexual Dimorphism: sexes alike

• Terrestrial

The habitat of T. tarsier is primary and secondary rain forest, although this species usually prefers to live in secondary growth forest. This is probably because of the presence of many saplings, creepers, and bamboos in secondary forest. Tarsius tarsier is usually found in dense patches of bushes, tall grasses, bamboos and small trees. (Macdonald, 1987)

Habitat Regions: tropical ; terrestrial

Terrestrial Biomes: forest ; rainforest ; scrub forest

Tarsius tarsier is both insectivorous and carnivorous, although there is much variation in diet between individuals. Its diet can consist of ants, beetles, cockroaches, scorpions, lizards, bats, snakes, birds, small mammals and others. It drinks several times each night by lapping up water with its tongue. Tarsius tarsier often uses its long fingers as a cage to trap its insect prey. It catches its other prey by leaping at it, pinning it to the ground, and then killing it with a few bites. It then takes its prey up to a perch and eats it head first. Tarsius tarsier eats almost all parts of its prey, even feathers, beaks, and feet. (Macdonald, 1987; Kavanagh, 1983)

Animal Foods: birds; mammals; reptiles; insects; terrestrial non-insect arthropods

Primary Diet: carnivore (Insectivore )

These animals are likely important in controlling and structuring the populations of their prey. To the extent that they are preyed upon by other animals, they may have some impact upon predator populations as well.

Because of its nocturnal and crepuscular habits, as well as its arboreal nature, owls are the most likley predators upon tarsiers.

Known Predators:

• owls

Communication in this species involves many elements. Tactile communication between mothers and their young, as well as between mates, is certainly of importance. In addition, these animals use complex vocalizations to space themselves and maintain contact while foraging. Scent marking, with urine as well as glandular secretions, occurs. Although visual communication has not been documented, it is likely that these animals use various body postures and other visual signals in communication.

Communication Channels: tactile ; acoustic ; chemical

Other Communication Modes: choruses ; scent marks

Perception Channels: visual ; acoustic

Although data are not available on the lifespan of this species, another member of the genus, T. syrichta, is reported to have lived 13.5 years in captivity. Tarsius tarsier is likely to have a similar maximum lifespan.

Each tarsier pair is essentially monogamous.

Mating System: monogamous

Breeding of Tarsius tarsier occurs throughout the year. Thus births occur throughout the year. The gestation period is approximately 6 months. Females give birth to only one offspring at a time.

(Hill, 1955; Schultz, 1969; Macdonald, 1987)

Although further details about reproduction are not available for this species, other tarsier species are better studied. The estrus cycle of Tarsius syrichta lasts from 18 to 27 days. Tarsius syrichta undergoes a 1 to 3 day estrus period. Young are fairly well-developed at brith, weighing approximately 20 to 31 g. Young are able to leap by about 1 month of age. The period of nursing is short, lasting about 45 days. At this age, the young are able to capture prey and may be weaned at any time thereafter. It is likely that T. tarsier resembles other members of the genus with regard to these characteristics.

Breeding interval: The breeding interval for these animals has not been reported, but based on length of gestation and nursing, these tarsiers may be able to reproduce every 9 or 10 months.

Breeding season: Breeding occurs throughout the year.

Average number of offspring: 1.

Average gestation period: 6 months.

Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization ; viviparous

The young are born in a fairly advanced condition (precocial). The newborn is already well furred, has open eyes and it is able to scramble around the branches, athough it usually travels by clinging to the fur on the abdomen of its mother with both hands and feet. Sometimes the mother carries the newborn in her teeth so as to leave her hands and feet free for leaping and clinging to trees. The young tarsier cannot leap until it is a month old. Instead, it moves around on the ground by shorts hops. At the age of 3 weeks, the baby begins to accept living food.

Parental Investment: precocial ; pre-fertilization (Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female); extended period of juvenile learning

Tarsius tarsier is very 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. In both Indonesia and Malaysia, there are laws designed to protect the tarsiers. (Macdonald, 1987)

CITES: appendix ii

IUCN Red List of Threatened Species: vulnerable

As mentioned above, these animals carry parasites which can affect humans who try to keep them as pets. However, in their natural environment, they do not pose a significant threat to humans.

Negative Impacts: injures humans (causes disease in humans )

One of the ways in which T. tarsier is important to biologists is that it has a crucial systematic position between other prosimians and monkeys, which makes tarsiers relevant to many of the problems of primate evolution. Because of their small size, gentle temperament, and ability to be tamed, many people attempt to make pets out of these animals. Problems arise because T. tarsier is a somewhat delicate creature, and requires live food. Usually, when kept as pets, these creatures die in a matter of days. There have actually been cases when a captured tarsier has become so traumatized that it killed itself by banging its head against the bars of its cage. Another reason keeping T. tarsier as a pet is not a good idea is that all tarsiers which have been examined have been found to have some forms of intestinal worms, such as hookworms and tapeworms, to which humans are susceptible.

(Macdonald, 1987)

Positive Impacts: pet trade ; research and education