The pygmy tarsier (''Tarsius pumilus''), also known as the mountain tarsier or the lesser spectral tarsier, is a

nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

primate found in central

Sulawesi Sulawesi (), also known as Celebes (), is an island in Indonesia. One of the four Greater Sunda Islands, and the world's eleventh-largest island, it is situated east of Borneo, west of the Maluku Islands, and south of Mindanao and the Sulu Ar ...

, Indonesia, in an area with lower vegetative species diversity than the lowland tropical forests. The pygmy tarsier was believed to have become extinct in the early 20th century. Then, in 2000, Indonesian scientists accidentally killed one while trapping rats. The first pygmy tarsiers seen alive since the 1920s were found by a research team led by Dr. Sharon Gursky and Ph.D. student Nanda Grow from Texas A&M University on

Mount Rore Katimbo Mount is often used as part of the name of specific mountains, e.g. Mount Everest. Mount or Mounts may also refer to: Places * Mount, Cornwall, a village in Warleggan parish, England * Mount, Perranzabuloe, a hamlet in Perranzabuloe parish ...

in Lore Lindu National Park in August 2008. The two males and single female (a fourth escaped) were captured using nets, and were radio collared to track their movements. As the first live pygmy tarsiers seen in 80-plus years, these captures dispelled the belief among some primatologists that the species was extinct.

Description

The pygmy tarsier has a head-body length of , and weighs less than , which makes it smaller and lighter than other

tarsier Tarsiers ( ) are haplorhine primates of the family Tarsiidae, which is itself the lone extant family within the infraorder Tarsiiformes. Although the group was once more widespread, all of its species living today are found in Maritime Southeast ...

species. Likewise, its ears are also smaller than those of the rest of genus '' Tarsius''. Its fur is tan or buff with predominant grey or brownish red coloring. Its tail is heavily haired and ranges from , and functions in balance when leaping. The pygmy tarsier has nails on all five digits of each hand and on two digits of each foot. The claw-like nails aid in its grasping strength and are also used as an aid in its need for vertical support for feeding and movement. Pygmy tarsiers exhibit low sexual dimorphism, so both sexes are similar in size and appearance. The most noticeable feature of the pygmy tarsier are its large eyes, which are about in diameter. Unlike other nocturnal species, tarsiers lack a tapetum lucidum due to the diurnal evolutionary history of primates. To make up for this, tarsiers have evolved their large eyes to maximize available light. Tarsiers eyes cannot move in their sockets, but their necks have the ability to turn their heads almost 360 degrees.

Habitat

The pygmy tarsier is endemic to the mossy cloud forests of central Sulawesi, Indonesia and found at altitudes of . The canopy of the mountain forests are low in height and undergrowth is much denser than the lowland forests. The plant diversity is low and covered in thick mosses, resulting in decreased habitat productivity. Pygmy Tarsiers handle this challenging habitat by living at the edge of forests where prey is more abundant.

Diet

Pygmy tarsiers are

insectivorous A robber fly eating a hoverfly An insectivore is a carnivorous animal or plant that eats insects. An alternative term is entomophage, which can also refer to the human practice of eating insects. The first vertebrate insectivores were ...

, feeding primarily on arthropods. Due to their arboreal lifestyle, their diet consists of airborne insects found in the forest canopy such as moths, grasshoppers, and katydids.

Behavior and ecology

The pygmy tarsier is found in stable bonded pairs, remaining together for up to 15 months. This stable pair bond is usually monogamous. The species has two breeding seasons, one at the beginning of the rainy season and the other at the end, separated by about 6 months.

Gestation Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregna ...

lasts 178 days on average, and births occur in May and from November to December. Infants are quite precocial, and develop quickly, similar to other juveniles in the genus. The offspring begin capturing their own prey around 42 days of age, and travel in groups after only 23 days. Young females remain with parents until adulthood, while young males leave the natal group as juveniles. The pygmy tarsier is

crepuscular In zoology, a crepuscular animal is one that is active primarily during the twilight period, being matutinal, vespertine, or both. This is distinguished from diurnal and nocturnal behavior, where an animal is active during the hours of daylig ...

, and is mainly arboreal. It spends most of the daylight hours sleeping on vertical branches in the canopy. ''T. pumilus'' is not a nest builder. Unlike other tarsier species, it does not use scent glands to mark territorial boundaries. Also tactile communication and interaction is important with the pygmy tarsier, as in other tarsier species. Some species of tarsier have recently been found to communicate at ultrasonic frequencies of around 70 kHz on the islands of Bohol and Leyte. The ultrasonic range of their communication is well beyond what may be detected by the human ear and is a distinct advantage to keeping their communication species-specific.

References

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