Tarsier
Tarsius

TAXONOMY

Suborder: Haplorrhini
Infraorder: Tarsiiformes
Family: Tarsiidae
Genus: Tarsius
Species: T. bancanus, T. dentatus, T. lariang, T. pelengensis, T. pumilus, T. sangirensis, T. syrichta, T. tarsier
Subspecies: T. b. bancanus, T. b. borneanus, T. b. saltator

Other names: T. bancanus: Horsfield's tarsier, western tarsier; tarsier de Bornéo (French); västligt spökdjur (Swedish); T. b. borneanus: Bornean tarsier; T. b. saltator: Belitung Island tarsier; T. dentatus: T. dianae, Dian's tarsier, Diana tarsier; T. lariang: Lariang tarsier; T. pelengensis: Peleng tarsier, Peleng Island tarsier; T. pumilus: Lesser spectral tarsier, pygmy tarsier, mountain tarsier; tarsero piemeno (Spanish); dvärgspökdjur (Swedish); T. sangirensis: Sagihe Island tarsier, Sangihe tarsier; T. syrichta: Philippine tarsier, Phillipine tarsier; tarsier des Philippines (French); filippinskt spökdjur (Swedish); T. tarsier: T. spectrum, Eastern tarsier, spectral tarsier, Sulawesi tarsier; tarsier des Célèbes (French); östligt spökdjur (Swedish).

The taxonomy of the tarsiers is debated and some authors include more forms that are not included here (see Brandon-Jones et al. 2004). Groves (2005) recognizes 7 species of tarsier, with only T. bancanus separated at the subspecific level. Here, the taxonomy of Groves is followed, and includes the recently described T. lariang as a full species as per Merker & Groves (2006). Very little is known about some of the tarsier species, especially T. pumilus, which has been identified from only three specimens (Shekelle 2003). Further, there is some debate as to the proper Latin name of the spectral tarsier (see Gursky 2007a). Some researchers still use T. spectrum for the species, but here T. tarsier is used as per Groves (2005). The tarsier population on Siau Island, Indonesia is recognized as specifically distinct but is as of yet unnamed (Mittermeier et al. 2007).

MORPHOLOGY

Tarsius syrichta
Photo: David Haring

In general, tarsiers are among the smallest of the prosimians, and are relatively hard to distinguish from one another purely on differences in pelage (Musser & Dagosto 1987; Ankel-Simons 2007). At the basic level, most of the pelage is grey with some, or some combination of, red, brown, yellow, orange, or buff (Niemitz 1979; 1984). The ends of the hairs can be dark red, brownish, or black with a grey base (Niemitz 1979; 1984). Further, there is often significant inter- and intra-specific overlap as well as variation in pelage by population and geographic location such that coloration is not a reliable indicator to distinguish all species from one another (Niemitz 1979; 1984). However, there are some distinct differences between the species in coloration. T. tarsier for example, has white spots behind its ears and a scaly underside of the tail, traits which the other species do not possess (Musser & Dagosto 1987; Groves 1998). Further, T. bancanus and T. syrichta have more yellow and a more pale coloration than T. tarsier (Musser & Dagosto 1987).

Among the species, the amount of tail hair is variable, decreasing from the hairiest tails found on the Sulawesi tarsiers (T. tarsier, T. pumilus, and T. dianae) to the intermediate T. bancanus, to the least hairy tail possessed by T. syrichta which is usually considered naked (Musser & Dagosto 1987; Gursky 2007a). Other means by which the species are, in varying degrees, determined from one another include eye size, dentition, and limb proportions (Gursky 2007a). T. pumilus is easily distinguished by its diminutive body size relative to the other species of tarsier whose body sizes often overlap with one another (Musser & Dagosto 1987; Maryanto & Yani 2004).

Head and body lengths of adults average 12.9-13.2 cm (5.1-5.2 in) (T. bancanus), 11.4-12.5 cm (4.5-4.9 in) (T. bancanus saltator), 11.8 cm (4.6 in) (T. dentatus), 9.7 cm (3.8 in) (T. pumilus), 12.4-12.8 cm (4.9-5.0 in) (T. tarsier) and 11.7-12.7 cm (4.6-5.0 in) (T. syrichta) (Niemitz 1984e; Musser & Dagosto 1987; Niemitz et al. 1991; Yustian 2007). However, in one wild study, average head and body lengths for spectral tarsiers (T. tarsier) were significantly higher at 24.3 cm (9.6 in) (male) and 23.0 cm (9.1 in) (female) (Gursky 2007a). The tail is roughly twice the head and body length (Shekelle 2003). Several species of tarsiers are sexually dimorphic, with males larger in body size than females (Neri-Arboleda et al. 2002; Gursky 2007a). Recorded adult body weight ranges including non-pregnant females are 104-135 g (3.7-4.8 oz) (M) and 95-110 g (3.4-3.9 oz) (F) (T. dentatus), 150 g (5.3 oz) (M) and 143 g (5.0 oz) (F) (T. sangirensis), 119-153 g (4.2-5.4 oz) (M) and 110-132 g (3.9-4.7 oz) (F) (T. syrichta), 67-112 g (2.4-4.0 oz) (M) and 72-109 g (2.5-3.8 oz) (F) (T. lariang), 110-138.5 g (3.9-4.9 oz) (M) and 100-119 g (3.9-4.2 oz) (F) (T. bancanus borneanus), 121.4-123.0 g (4.28-4.33 oz) (M) and 101.2-108.5 g (3.6-3.8 oz) (F) (T. bancanus saltator), 104-132 g (3.7-4.7 oz) (M) and 94-119 g (3.3-4.2 oz) (F) (T. tarsier), and 57.5 g (2.0 g) (F) (T. pumilus) (Rickart et al. 1993; data compiled by Shekelle 2003; Maryanto & Yani 2004; Merker & Groves 2006; Yustian 2007).

Tarsius lariang
Photo: Stefan Merker

Unique spinal morphology makes tarsiers capable of turning their heads nearly 180° in each direction, allowing them the ability to rotate their heads almost 360° (Ankel-Simons & Simons 2003; Ankel-Simons 2007). All tarsiers have claws on the second and third digits, two grooming claws on their feet, and pads on each of their fingers (Ankel-Simons 2007). Several bones of the heel (tarsals) are longer than those of any of the primates, and the genus name Tarsius partially describes this trait (Ankel-Simons 2007). Further, the amount of fur on the heel can be used to distinguish some tarsiers from one another. For example, while the heels of most tarsiers are fully furred, T. syrichta heels have very little, sparse, fine hair only, giving the appearance of being hairless in contrast to the rest of the body (Musser & Dagosto 1987: Ankel-Simons 2007). The nose is dry (Ankel-Simons 2007).

Tarsiers move through their environment predominantly, but not exclusively, through leaping (MacKinnon & MacKinnon 1980; Niemitz 1985; Crompton & Andau 1986; Dagosto et al. 2001; Gursky 2007a). The tarsier body is well adapted for leaping. In addition to the unique heel morphology, the legs and their muscles comprise around a quarter of the weight of the entire body (Niemitz 1985). Due to their morphology, tarsiers are capable of leaping quite far, with T. bancanus able to leap over 5 m (16.4 feet) (Niemitz 1983). Other forms of locomotion include bipedal and quadrupedal climbing, quadrupedal walking, clambering and hopping (MacKinnon & MacKinnon 1980; Niemitz 1984c; Crompton & Andau 1986; Dagosto et al. 2001). The proportions of different locomotor activity differ with species however, and in some cases sets species apart from one another (Dagosto et al. 2001). Furthermore, locomotion in the wild is extremely quiet (MacKinnon & MacKinnon 1980).

The oldest living captive tarsier was over 16 years old when it died (Weigl 2005).

RANGE

Tarsiers are restricted to the Southeast Asian island nations of Brunei, Indonesia, Malaysia, and the Philippines (Shekelle et al. 1997; Brandon-Jones et al. 2004). On morphological grounds, the tarsiers are often divided into two geographic groups; a Philippine-Western group and an Eastern group (Brandon-Jones et al. 2004). T. syrichta is restricted to the Philippines; found on the southern islands of Bohol, Dinagat, Leyte, Mindanao, Samar, and Siargao (Gursky 1999). The range of T. bancanus stretches between and includes southern Sumatra and Borneo, including the islands of Bangka, Belitung and Karimata (midway between Sumatra and Borneo), as well as Serasan (just off the northwest coast of Borneo) (Gursky 1999). Subspecifically, T. b. bancanus is found on Sumatra, from the Musi River to the Sunda Strait. T. b. borneanus is found throughout the island of Borneo. T. b. saltator is found on Belitung Island (Brandon-Jones 2004). East of Borneo, several species of tarsier call the island of Sulawesi home, including T. dentatus, T. lariang, T. pumilus, and T. tarsier (Gursky 1999; Merker & Groves 2006). T. pumilus is restricted to the central Sulawesian mountainous mossy and cloud forests (Simons 1987; Shekelle et al. 1997; Maryanto & Yani 2004). The distribution of T. lariang, while only tentatively established, is suspected to encompass west-central Sulawesi (Merker & Groves 2006). T. dentatus is found in central Sulawesi (Niemitz et al. 1991; Shekelle et al. 1997; Gursky 1999). T. sangirensis is restricted to the Greater Sangihe Island, north of Sulawesi (Shekelle et al. 1997; Groves 1998). The spectral tarsier (T. tarsier) is reported from Sulawesi and some surrounding islands (Niemitz 1984e; Musser & Dagosto 1987). However, as more tarsier diversity is recognized on Sulawesi, the range of T. tarsier continues to shrink, and the species may only be found in northern Sulawesi (Gursky 1998). T. pelengensis is found on Peleng Island off of the east coast of Sulawesi (Shekelle et al. 1997).

T. bancanus range (in green)
T. syrichta range (in red)
Sulawesi/eastern tarsiers range (in yellow)

Population totals in the wild are unknown, however the as-yet undescribed Tarsius species inhabiting Siau Island, Indonesia is listed as one of the World's 25 Most Endangered Primates, and at most, likely numbers only one thousand or a few thousand individuals (Mittermeier et al. 2007).

HABITAT

Tarsiers are found in a broad variety of habitats, including primary and secondary habitats, as well as certain habitats under human cultivation or use (MacKinnon & MacKinnon 1980; Crompton & Andau 1986; Yustian et al. 2008). Habitats in which tarsiers have been found include primary, secondary, mossy, microphyll, montane, bush, gallery, deciduous rain, and mangrove forests; thorn scrub, shrubland, swamps, riverine, palm, and bamboo habitats, seashore scrub, and even urban gardens, villages and grassland (MacKinnon & MacKinnon 1980; Crompton & Andau 1986; Leksono et al. 1997; Neri-Arboleda et al. 2002; Riley 2002; Maryanto & Yani 2004; Gursky 2007a). However, grassland is usually used only to travel between other suitable habitats (Neri-Arboleda et al. 2002). Secondary habitats in which tarsiers can be found include those which have been selectively and intensively logged; those containing coffee, nutmeg, coconut or coca plantations; areas being cut for bamboo and rattan extraction, and forests in which intensive or small-scale agricultural activities are taking place (Riley 2002; Merker 2006; Yustian et al. 2008). If found in secondary, degraded, or habitats under human use, tarsiers require at least the presence of some suitable dense shrubs, forest remnants or bamboo stands to provide the proper sleeping sites (Leksono et al. 1997; Merker & Yustian 2008). In addition, population densities are lower in more disturbed habitats (Merker 2003). Tarsiers can range from sea level to as high as 1500 m (4921.3 ft), with the exception of T. pumilus, which can be found as high as 2200 m (7217.8 ft) (MacKinnon & MacKinnon 1980; Shekelle 2003; Maryanto & Yani 2004).

At one long term study site near the Lore-Lindu National Park on Sulawesi, an average of 270 cm (106.3 in) of rain falls annually. The temperature varies little over the course of the year, but temperatures average highs of 32.9°C (91.2°F) during the day and lows of 19.5°C (67.1°F) at night (Merker 2003 cited in Merker 2006). In northern Borneo at the Sepilok Forest Reserve, there are two seasonal monsoons (December-January and July) during which much of the annual 314.7 cm (123.9 in) of rain falls. At this site the temperature averages 26.7°C (80°F) (Crompton & Andau 1987).

ECOLOGY

Tarsius bancanus
Photo: David Haring

Tarsiers eat only prey and are the only entirely rapacious primates, consuming no plant matter whatsoever (Fogden 1974; Niemitz 1984d; Jablonski & Crompton 1994; Gursky 2007b). However, there are differences among the tarsiers in the types of animal matter that are consumed as well as seasonal changes in consumption. For example, T. bancanus eat arthropods mostly, including beetles, cockroaches, grasshoppers, butterflies, phasmids and cicadas. This species will also eat small birds, and other prey such as bats, frogs, freshwater crabs and snakes (Niemitz 1973; 1979; Jablonski & Crompton 1994). Contrary to this, T. tarsier has not been seen to eat birds, snakes, or other prey, but is the most insectivorous of the primates, eating exclusively arthropods, including spiders, beetles, termites, cicadas, ants, moths, caterpillars, katydids, crickets, grasshoppers, cockroaches and walkingsticks (MacKinnon & MacKinnon 1980; Gursky 2000b; 2007). T. syrichta consumes similar foods, including orthopterans, lepidopterans, beetles, ants, and termites (Dagosto et al. 2003). Further, there are seasonal shifts in the types of prey consumed as well as in the locations of the procurement of prey between the dry and wet seasons in T. tarsier (Gursky 2000b). The diets of T. syrichta and T. pumilus are unknown (Gursky 2007b).

T. tarsier procures its prey directly from the air (34.8%), the ground (7.8%), from leaves (46.3%) and from branches (11.1%) (Gursky 2000b). In captivity, T. bancanus used three main methods of capturing prey with an overall 88% success rate; reaching out and grabbing prey without moving, leaping onto prey, or leaping several times towards and then onto potential prey (Roberts & Kohn 1993).

Estimated home range averages are 0.006-0.065 km² (0.002-0.03 mi²) (T. syrichta), 0.023-0.031 km² (0.009-0.01 mi²) (T. tarsier), 0.005-0.018 km² (0.002-0.005 mi²) (T. dentatus), 0.045-0.1125 km² (0.02-.04 mi²) (T. bancanus), 0.023-0.103 km² (0.009-0.04 mi²) (T. bancanus saltator) (Crompton & Andau 1986; 1987 Tremble et al. 1993; Dagosto et al. 2001; Neri-Arboleda et al. 2002; Dagosto et al. 2003; Merker 2006; Gursky 2007a; Yustian 2007). Mean nightly path distances for T. tarsier average 476.0 m (1561.7 ft) for females and 782.9 m (2568.6 ft) for males (Gursky 2007a). T. bancanus travels an average of 1800 m (5905.5 ft) nightly and T. bancanus saltator travels between 768 and 1061 m (2519.7 and 3481.0 ft) per night on average (Crompton & Andau 1986; Neri-Arboleda et al. 2002; Yustian 2007). T. syrichta travels an average of 1119 m (3671.3 ft) (F) and 1636 m (5367.5 ft) (M) per night (Neri-Arboleda et al. 2002). Home ranges increase in size with degree of human disturbance and degradation (Merker 2006). In T. syrichta and T. bancanus, home ranges overlap with individuals of the opposite sex, but only to a small degree with individuals of the same sex (Fogden 1974; Neri-Arboleda et al. 2002).

Tarsiers are nocturnal. T. bancanus usually awakes before sunset and does not retire for the night until after sunrise (Niemitz 1984a). There are peaks in leaping and movement in T. bancanus early and late in the night, a pattern also followed by T. dentatus (Crompton & Andau 1987; Merker 2006). As the hour of night progresses, the height of activities decreases (Crompton & Andau 1987). Spectral tarsiers (T. tarsier) spend their time foraging (55%), followed by traveling (23%), resting (16%) and in social activities (6%) (Gursky 2005a; 2007a). Spectral tarsiers (T. tarsier) alter their activity patterns between the wet and dry seasons. In the dry season, when resources are less available, travel distance and home range are expanded, resulting in increased numbers of intergroup encounters. In addition, time spent in social activities is shortened in the dry season, and a dietary shift is seen to smaller insect prey, as well as ground-dwelling varieties (Gursky 2000b). Further, spectral tarsiers (T. tarsier) are more active during full moons (Gursky 2003a).

Tarsiers are most often found less than one or two meters (3.3 or 6.6 feet) above the ground (Crompton & Andau 1986; Tremble et al. 1993; Dagosto & Gebo 1996/1997).

Potential predators of tarsiers include civets, arboreal snakes, monitor lizards, and raptors including owls (Gursky 1997; Jachowski & Pizzaras 2005; Gursky 2002c). Feral cats are also predators of tarsiers (MacKinnon & MacKinnon 1980; Jachowski & Pizzaras 2005). Among wild spectral tarsiers (T. tarsier), if a snake threat is identified, all members of a group will travel towards the predator and will mob it, lunging, vocalizing, and even biting the threat (Gursky 2002b; 2002c). Interestingly, while spectral tarsier groups do not contain more than one adult male, during the mobbing of a predator, often more than one adult male is present, indicating the presence of males from more than one group (Gursky 2002c; 2005b;2006).

Sleeping sites of T. syrichta are typically dense tangles of vegetation near large trees and close to the ground and each tarsier normally uses several (3-4), each located near the edges of its range (Dagosto et al. 2003). In a semi-wild environment, sleeping sites in the species are usually around 2 m (6.6 ft) off the ground (Jachowski & Pizzaras 2005). Contrastingly, both T. dentatus and T. tarsier usually use only one sleeping site and rarely two or three, but they are also located near the edges of the home range (Merker 2006; Gursky 2007). T. dentatus prefers dense vegetation or tree cavities for sleeping (Tremble et al. 1993). T. bancanus sleeps in vegetation tangles between 3.5 to 5 m (11.5 to 16.4 ft) off the ground (Crompton & Andau 1986). T. sangirensis sleeps on exposed bamboo, the tops of palm leaves, or at the tops of trees, unlike all other species of tarsier (Shekelle et al. 1997). While not active during the day, if disturbed or threatened, tarsiers will leave their sleeping sites (Yustian 2007).

Content last modified: July 22, 2008

Written by Kurt Gron.

Cite this page as:
Gron KJ. 2008 July 22. Primate Factsheets: Tarsier (Tarsius) Taxonomy, Morphology, & Ecology . <http://pin.primate.wisc.edu/factsheets/entry/tarsier>. Accessed 2010 February 9.