Tarsius pumilus
pygmy tarsier

Tarsius pumilus is endemic to central Sulawesi, Indonesia, in the altitudinal range of 1,800 to 2,200 m (montane rain forest habitats). (Musser & Dagosto, 1987) (Musser, Dagosto, and March 12, 1987)

Tarsius pumilus is found in tropical mossy upper montane rain forests at elevations between 1,800 and 2,200 meters in the central Sulawesi mountains. The mountains are covered in a thick, gray mist when it is not raining. The cool mountain air mixes with humidities between 85 and 100%, to create a clammy, cold, and wet environment. The forest is usually open and parklike, blanketed in mosses with tangles of rotting tree falls and dense undergrowth beneath. In upper montane forests, the canopy is only 10 to 20 meters high, leaves are small, tree trunks are not buttressed, large woody vines are absent, and species diversity of trees and shrubs is lower than in lowland tropical rainforest. (Musser & Dagosto, 1987) (Musser, Dagosto, and March 12, 1987)

Of the four species of tarsiers, T. pumilus is one of the most morphologically distinct. Males and females are not sexually dimorphic. Tarsius pumilus is strongly distinguished by its small body size. Head and body length is 85 to 160 mm, only 75% that of the other three species of tarsiers. These animals weigh only 80 to 165 g.

Ears in this species are smaller than those of Tarsius tarsier. The pelage, similar to that of T. tarsier, is buff, predominantly gray or brownish-red. These two species also have in common a white, or pale brown, postauricular spot. Pelage of T. pumilus is longer, denser, and silkier than that of T. tarsier. Hair is sparse on certain parts of the body. The underbelly of T. pumilus is buff, grayish, or slate colored.

Tail length is 135 to 275 mm. The tail is heavily haired and dark brown or black. Approximately one third of the ventral surface of the tail is scaly, which is attributed to its function in body posture.

The most prominent structural features of tarsiers are their large, forward pointing eyes, usually 16 mm in diameter. Tarsius pumilus, like T. tarsier, has short fore limbs and small hands, suggesting that these animals use their hands more for locomotion than for immobilizing prey, as do other tarsier species.

Tarsius pumilus has nails on all five digits of the hand, including the hallux, and on the two lateral digits of the foot. These nails are laterally compressed and are sharply pointed at the tips, resembling claws. The specialized claw-like nails on T. pumilus have been attributed to their need for grasping strength in using large vertical supports for feeding and locomotion. The hands and feet of T. pumilus have digital pads that are reduced in size as compared to the digital pads on other species of tarsiers. This feature too, is thought to give T. pumilus a better grasp on the mossy substrate to which it clings during feeding and locomotion. Unlike other tarsiers, the tips of the nails extend beyond the edge of the digital pads. (Musser & Dagosto, 1987; Nowak, 1999) (Musser, Dagosto, and March 12, 1987; Nowak, 1999)

A captive Tarsius syrichta lived for 13.5 years. It is likely that the lifespan of T. pumilus is similar. (Nowak, 1999)

Tarsiers are nocturnal or crepuscular and mainly arboreal. In the dense vegetation of its habitat, T. pumilus spends most of the day sleeping on vertical branches or possibly in hollow trees. When clinging to a vertical branch, the tail of T. pumilus is often braced against the vertical support and functions in supporting the body. When sleeping, the head of T. pumilus tends to drop downward between the shoulders. If disturbed while resting, these animals may move up and down the vertical support with the face presented towards the enemy, mouth open, and teeth bared. When waking, the ears of T. pumilus are furled or crinkled continuously.

These animals do not build nests. They have a wide field of vision and can rotate the head nearly 360 degrees. They can effortlessly leap several meters from tree to tree. Their leaps tend to be froglike. On a flat surface, their leaps can be from 1,200 to 1,700 mm long, and up to 600 mm high. The tail is arched over the back as an individual leaps. When walking on all fours, however, the tail hangs down.

Tarsius tarsier, and possibly T. pumilus, is territorial. These tarsiers actively chase others out of their home ranges and mark their core areas by rubbing the branches with urine and epigastric glands.

There is no evidence that anyone has ever recorded the vocalizations of the small bodied, montane T. pumilus. As a result, it is unknown whether the vocalizations of T. pumilus are similar to the loud shrieks during territorial battles and loud duets between the males and females found in T. tarsier, but it is likely that there is some similarity (Musser & Dagosto, 1987; Nowak 1999) (Musser, Dagosto, and March 12, 1987; Nowak, 1999)

Tarsiers use chemical signals to mark their territories. In addition, although the calls of T. pumilus have not been recorded, other members of the genus do make vocalizations, which have some territorial significance. It is likely that T. pumilus is similar in this respect.

In all primate species tactile communication is important between mothers and their offspring, as well as between mates.

The extent to which tarsiers use visual signals, such as postures and displays, is not known.

Tarsiers are primarily insectivorous. Tarsius pumilus eats primarily arthropods with heavily keratinized exoskeletons. Prey are caught by a sudden leap and chewed with a side to side motion of the jaw. Tarsius pumilus drinks water by lapping. (Musser & Dagosto, 1987; Nowak, 1999) (Musser, Dagosto, and March 12, 1987; Nowak, 1999)

Details on predation of these animals are lacking. However, it is likely that small carnivorous mammals may take them as prey. In addition, they may fall prey to raptors and snakes.

As insectivores, these animals may help to structure the insect community and play an important role in local food webs.

No potential adverse affects have been recognized.

No potential benefits have been recognized.

IUCN: indeterminate

In general, tarsiers are threatened by destruction of forests and being captured by people. (Nowak, 1999)

Tarsius pumilus was first named and described in 1921, but later considered a subspecies of T. tarsier. Only in the past fifteen years has T. pumilus regained its specific status. (Musser & Dagosto, 1987) (Musser, Dagosto, and March 12, 1987)