Tarsier

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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, T. tumpura, T. wallacei
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); T. tumpara: Siau Island tarsier.

Conservation status:  multiple

Life span: >16 years
Total population: Unknown
Regions: Brunei, Indonesia, Malaysia, Philippines
Gestation: 157 to 193 days (5.2 to 6.3 months)
Height: 9.7 cm to 13.2 cm (M & F)
Weight: 57.5 to 153 g (M & F)

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 had been known from only three museum specimens until the recent rediscovery of a wild population (Musser & Dagosto 1987; Shekelle 2003; Gursky-Doyen & Grow 2009; in review). Further, there is some debate as to the proper Latin name of the spectral tarsier (see Gursky 2007a). Much of the literature on spectral tarsiers refers to the species as T. spectrum, and many researchers continue to do so (e.g. Gursky 2007a), but here T. tarsier is used as per Groves (2005). The tarsier population on Siau Island, Indonesia, which has been recognized as specifically distinct, has been recently named T. tumpara (Mittermeier et al. 2007; Shekelle et al. 2008). In 2010, Merker et al. described a new species of tarsier located in central Sulawesi, T. wallacei (Merker et al. 2010).

MORPHOLOGY

Tarsier clinging tree
Tarsius

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 48.1-50.1 g (1.7-1.8 oz) (M) and 52.0-57.5 g (1.8-2.0 oz) (F) (T. pumilus) (Rickart et al. 1993; data compiled by Shekelle 2003; Maryanto & Yani 2004; Merker & Groves 2006; Yustian 2007; Grow and Gursky in press).

Tarsier clinging branch
Tarsius

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

CURRENT RANGE MAPS (IUCN REDLIST):
Tarsius bancanus | Tarsius dentatus | Tarsius lariang | Tarsius pelengensis | Tarsius pumilus | Tarsius sangirensis | Tarsius syrichta | Tarsius tarsier

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 montane mossy 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). T. tumpara is found only on Siau Island, part of the Sangihe Island chain (Shekelle et al. 2008). 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).

Population totals in the wild are unknown, however population density surveys have revealed tarsiers live in medium to low densities. The Siau Island tarsier 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; Shekelle et al. 2008). On mainland Sulawesi, a population density survey of spectral tarsiers sampled 156 individuals per square kilometer (Gursky 1998). T. dianae population density can reach 268 individuals per square kilometer in less disturbed habitat, but drops to 45 in habitats heavily disturbed by human activity (Merker et al. 2005). In the Philippines, T. syrichta lives at 57 individuals per square kilometer in fragmented forest (Neri-Arboleda et al. 2002). Based on low trapping success rates, T. pumilus is thought to live at an extremely low density (Gursky-Doyen & Grown 2009).

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

Tarsier clinging branch
Tarsius

Tarsiers eat only prey and are the only entirely carnivorous 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: December 1, 2010

Written by Kurt Gron. Reviewed by Nanda Grow.

Cite this page as:
Gron KJ. 2010 December 1. Primate Factsheets: Tarsier (Tarsius) Taxonomy, Morphology, & Ecology . <http://pin.primate.wisc.edu/factsheets/entry/tarsier/taxon>. Accessed 2020 July 9.

SOCIAL ORGANIZATION AND BEHAVIOR

Tarsiers exhibit variation in social system between species. The best descriptor of T. tarsier social system may be monogamous with facultative polygyny, where one male’s range overlaps with that of another female, and sometimes with multiple females whose ranges overlap (Gursky 1995; 2007a). Genetic evidence suggests that T. lariang may also have a monogamous mating system (Driller et al. 2009). Tarsiers outside of Sulawesi do not appear to have a monogamous social organization. A dispersed (noyau) mating system, where a male’s range overlaps multiple female ranges, characterizes sociality among T. bancanus and T. syrichta (Crompton & Andau 1987; Dagosto et al. 2001; Neri-Arboleda et al. 2002).

In general, the western tarsiers (T. bancanus) are the least gregarious, followed by the intermediate Philippine tarsier (T. syrichta), and finally with the eastern species (all other species) showing the highest levels of sociality (Shekelle 2003). Sociality within a tarsier species varies with resource availability and predation. Spectral tarsiers decrease distances between group members during times of higher food resource availability and increased predation pressure (Gursky 2002b). T. dentatus also increases distances between individuals in more disturbed habitats with fewer resources (Merker et al. 2005). T. spectrum is considerably gregarious both in and out of the sleeping site, although outside the sleeping site group members usually are not in actual physical contact with one another (Gursky 2000c). At sleeping sites, typical T. tarsier social behaviors include playing, allogrooming, snuggling, vocalizing, and scent-marking, while social behaviors with group members away from the sleeping site include playing, allogrooming, snuggling, vocalizing, scent-marking, food-sharing, and copulating (Gursky 2000c).

Two Tarsiers
Tarsius

Group size and composition varies both within and between tarsier species. In spectral tarsiers (T. tarsier), there is significant variation in group size (the number of individuals who share a sleeping site) and composition (Gursky 1995). The average group size of T. tarsier is 3.1 individuals and is comprised of at least a mated pair of adults but also sometimes with an additional adult female, and often offspring (MacKinnon & MacKinnon 1980; Gursky 1995; 2000b). Spectral tarsier groups do not contain more than one adult male (Gursky 2006). Similarly, Dian’s tarsier groups usually consist of one adult male, one or more adult females, and their offspring sharing a sleeping tree (Merker 2006). This species decreases group size in disturbed habitats with fewer resources (Merker et al. 2005). In contrast, T. bancanus do not sleep with other tarsiers and are usually found solitary (Crompton & Andau 1987). T. syrichta are almost always alone as well.

Tarsiers engage in territorial behaviors including defense through patrolling and social encounters, as well as territorial advertisement through scent-marking and vocalizations. Territorial defense is seen in the spectral tarsier (T. tarsier) and likely functions most importantly in mate defense but also may have other functions as well (Gursky 2003b; 2007a). Territorial disputes in this species usually occur near the edges of a group’s territory, and consist of group members aggregating, calling toward, chasing and lunging at the intruder (MacKinnon & MacKinnon 1980; Gursky 2003b; 2007a). T. bancanus males also patrol their territories (Crompton and Andau 1986). In Sulawesi, vocalizations may function as territorial advertisement, where both males and females of T. tarsier, T. dentatus, and T. lariang perform morning duet vocalizations (Gursky 2007a; Merker et al. 2005; Merker & Groves 2006). Both T. tarsier and T. syrichta mark territory by depositing scent-marks within and along home range boundaries (Gursky 1997; Neri-Arboleda et al. 2002). T. dentatus establishes sleeping sites near the periphery of home ranges, which may aid in the renewal of scentmarks along territorial boundaries (Merker 2006).

Both sexes of spectral tarsier (T. tarsier) disperse from their natal sleeping sites. Males disperse on average 733 meters (2404.9 ft), much farther than the female average of 360 meters (1181.1 ft) (Gursky 2007a).

REPRODUCTION

The female sexual cycles of T. bancanus in captivity last on average 24 days (Wright et al. 1986b). The sexual cycles of T. syrichta average 24.6 days (Catchpole & Fulton 1943). During estrus, the genitals of female T. bancanus swell and become reddish, a state that usually lasts for 6-9 days per cycle (Wright et al. 1986a; 1986b). In captivity, female T. bancanus solicit courtship by performing genital displays. Males then vocalize a “chirruping” call and sniff the genitals of the female. Both sexes may urinate. Courtship may last from 60 to 90 minutes but copulation itself lasts only around a minute and a half (Wright et al. 1986a). Copulation occurs on a vertical perch, with the male mounting the female in a dorsalventral position from behind and below. Post-copulation, the male will groom his genitals and the female will rub herself on various objects nearby (Wright et al. 1986a).

Wild spectral tarsiers (T. tarsier), unlike other tarsiers, reproduce seasonally, with two observed mating seasons between April-June, and again between October-November and corresponding birth peaks between April-May and November-December (MacKinnon & MacKinnon 1980; Gursky 2007a). The average inter-birth interval in wild T. tarsier is 13.5 months (Gursky 2007a).

Estimated average gestation length in wild T. tarsier is 193 days (6.3 months) (Gursky 2007a). Gestation in captive T. bancanus is around 178 days (5.9 months), while recorded values for T. tarsier and T. syrichta are 157 days (5.2 months) and 180 days respectively (5.9 months) (Izard et al. 1985; Roberts 1994).

T. bancanus females are capable of conceiving offspring at around two years of age and T. tarsier are sexually mature at around 518 days (17.0 months) (Roberts 1994).

PARENTAL CARE

Tarsier clinging branch
Tarsius

Relative to their parents, infant tarsiers are very large at birth (20-33% of adult weight) and are born with open eyes and fur (Roberts 1994; Gursky 2000a). Tarsier infants are born as singletons (Roberts & Kohn 1993; Gursky 2007a). In captivity, T. bancanus birth weights average 23.0 g (0.8 oz) and T. syrichta birth weights average 23.2 g (0.8 oz) (Haring & Wright 1989; Roberts & Kohn 1993).

Wild infant spectral tarsiers T. tarsier are carried in the mouth of the mother in the manner of a cat and almost never by clinging to the fur, a pattern which is also seen in T. syrichta (Haring & Wright 1989; Gursky 1994; 2007a). In some captive observations of T. bancanus, mothers carried their offspring orally, in other studies this was not the case with mothers never carrying their offspring orally (Niemitz 1984b; Roberts 1994). In the wild infant T. tarsier are carried about 20% the time overall, but carriage declines as the infant ages (Gursky 2007a).

The captive T. bancanus infant first moves away from its mother at 10-15 days old. Skilled locomotion commences in captive T. bancanus around 22-28 days old and mothers stop trying to carry their infant between 41 and 43 days old (Roberts 1994). T. tarsier and T. bancanus infants are able to move quadrupedally before they are able to leap (Gursky 1997). In wild T. tarsier, the first leaps are seen at 32 days old (Gursky 1997). Attempts to catch live prey in captive T. bancanus start at an average of 37 days old (Roberts 1994). However, in the wild, a T. tarsier infant was seen hunting at 26 days old (MacKinnon & MacKinnon 1980). Wild T. tarsier hunting success is first met at 45 days old (Gursky 1997). Captive play in T. bancanus begins at an average of 22.5 days old. Between 38 and 49 days old, the mother and infant start to sleep apart, and completely cease to do so by 75 days old. Wild T. tarsier nursing conflict peaks in the 8-9th weeks of life and infants are weaned at an average of 80 days of age (Gursky 2007a). Weaning occurs at 80 days in T. bancanus and 82 days old in T syrichta (Roberts 1994).

Perhaps the most interesting aspect of spectral tarsier (T. tarsier) infant rearing is the large amount of time the infant spends alone (Gursky 1994). While she forages, a wild mother will “park” her offspring and leave it by itself, occasionally visiting the infant (MacKinnon & MacKinnon 1980; Roberts 1985). However, the T. tarsier mother usually stays relatively close to the “parked” infant and will “park” it at an average of 11 different times over the course of the night (Gursky 2002a). Until 70 days of age, T. tarsier infants are “parked” more than half of the time, usually almost 6 m (19.7 ft) above the ground and not in particularly concealed locations (Gursky 1997).

Allocare is seen in wild spectral tarsiers (T. tarsier), and may be provided to the infant by subadults of both sexes and adult males with the most non-maternal allocare provided by subadult females (Gursky 2000a). Types of allocare that are seen include infant transport, food sharing, play, grooming, baby-sitting, physical contact, and increased vigilance and alarm calling (Gursky 2000a). While other group members sometimes carry the infant, the vast majority of transport is provided by the mother (Gursky 2000a).

Infanticide has occurred in captive T. bancanus (Roberts 1994).

COMMUNICATION

re noticeable differences in vocalizations between, and in some cases within tarsier species, and playback experiments with wild tarsiers have shown that such differences are recognized by the tarsiers themselves. The implications of this are that groups that have different vocalizations or duet structure may in fact be different cryptic species and that there may be more species than are currently recognized (Shekelle et al. 1997; Nietsch & Kopp 1998).

Several species of Sulawesian tarsier, including T. dentatus, T. tarsier, and T. lariang, duet at the end of their activity cycle, before sunrise near the sleeping site (Niemitz et al. 1991; Tremble et al. 1993; Shekelle 2003; Merker & Groves 2006). Vocal duets in T. tarsier occur regularly between mated pairs when they return to the sleeping tree, occurring roughly at the same time nearly every morning (Gursky 1997, 2000c; MacKinnon and MacKinnon 1980; Nietsch 1999, 2003). In this species, most duets are started by females and last several minutes (Gursky 2000c; Nietsch 2003). There may be multiple functions of vocal duets, including territorial displays and mate guarding (Gursky 1997; 2000c; MacKinnon and MacKinnon 1980; Nietsch 2003; Gursky 2007). T. pumilus do not perform duets when returning to their sleeping site, and may vocalize rarely (Grow & Gursky-Doyen in review). T. bancanus and T. syrichta do not perform duets (Nietsch 2003). In fact, wild T. bancanus are not very vocal at all at some study sites, while at others they are significantly so (Niemitz 1984f; Crompton & Andau 1987). T. bancanus has been reported to produce “calling concerts” in which several tarsiers call together, but such events are not analogous to the duets heard in other tarsiers (Crompton & Andau 1987).

There are a number of types of vocalizations produced by tarsiers that are not part of duets. For example, T. tarsier has 15 different types of calls, including distress calls, alarm whistles, alarm calls, mid-intensity alarm calls, female screams, contact trills, contact whistles, food calls, play whistles, infant squeaks and other types of whistles (Nietsch 2003). T. bancanus use four general types of vocalization (Niemitz 1984f).

Several postures in T. tarsier serve a communicatory function. Fear is communicated by folded ears while a crouched posture, an open mouth, and/or a lunge forward communicate a defensive threat. A bipedal stance with an open mouth is an aggressive threat (MacKinnon & MacKinnon 1980).

Tarsiers possess a gland in their lips as well as an abdominal gland, which, together with the anogenital region, function in olfactory communication when rubbed on substrates including other tarsiers (Niemitz 1979; MacKinnon & MacKinnon 1980; Wright et al. 1986; Crompton & Andau 1987; Shekelle 2003). All tarsiers of various ages and sexes urine mark as well (Niemitz 1979;MacKinnon & MacKinnon 1980). In fact, even if not seen or heard, tarsiers can be recognized as present in a given habitat purely by their scent marking alone (Niemitz 1979). T. bancanus of both sexes scent-mark and vocalize most often during female estrus and proestrus (Wright et al. 1986).

Content last modified: December 1, 2010

Written by Kurt Gron. Reviewed by Nanda Grow.

Cite this page as:
Gron KJ. 2010 December 1. Primate Factsheets: Tarsier (Tarsius) Behavior . <http://pin.primate.wisc.edu/factsheets/entry/tarsier/behav>. Accessed 2020 July 9.

SPECIAL NOTES

 

INTERNATIONAL STATUS

CONSERVATION STATUS

CITES: Appendix II (What is CITES?)
IUCN Red List: T. pelengensis, T. sangirensis: EN; T. bancanus, T. dentatus, T. tarsier: VU; T. syrichta: NT; T. lariang, T. pumilus: DD (What is Red List?)
Key: EN = Endangered, EN = Endangered, VU = Vulnerable, VU = Vulnerable, VU = Vulnerable, NT = Near threatened, DD = Data deficient, DD = Data deficient
(Click on species name to see IUCN Red List entry, including detailed status assessment information.)

Tarsier face
Tarsius

T. tumpara of Siau Island, Indonesia is considered one of the World’s 25 Most Endangered Primates and has been assessed as Critically Endangered (CR A1acd) under the IUCN Red List criteria (Mittermeier et al. 2007). Captive management of tarsiers is difficult and up until now has not met with great success, partially owing to the nutritional difficulties involved with a primate that eats only live food further complicated by its reproductive life-history. As a result, over half of the tarsiers caught in the wild die within two years in captivity and captive infant mortality is high (Fitch-Snyder 2003). Further, at no point have any of the Sulawesian tarsiers been held in captivity (Gursky 2007a).

CONSERVATION THREATS

Threat: Human-Induced Habitat Loss and Degradation

Habitat destruction, change, and fragmentation pose significant threats to tarsiers with T. bancanus, T. tarsier, and T. syrichta all having lost more than half of their original habitat (Wright et al. 1987; MacKinnon 1997; Gursky 1998; Yustian 2007). For example, on Sulawesi, rates of habitat destruction remain high, even within protected areas (Gursky 1998). Further, tarsiers are usually not found in areas with high human populations and those which are under intensive agricultural use (Leksono et al. 1997). T. b. saltator habitats are destroyed for palm and pepper plantations and due to tin mining (Yustian 2007). Logging reduces tarsier density by destroying preferred supports and sleeping sites and by producing loud noises which disturbs the animals (Merker & Mühlenberg 2000). Further, areas that have been logged are then susceptible to other activities such as the establishment of plantations, the raising of livestock, and settlement (Merker et al. 2005). Strangler figs are often removed from human-utilized forests because they threaten commercially valuable trees. Because spectral tarsiers (T. tarsier) prefer strangler figs as sleeping sites, such destruction may threaten the species (Gursky 1998). Some tarsiers, such as T. b. saltator are able to live in small patches of secondary harvested forest (Yustian 2007). While tarsiers can inhabit degraded areas, secondary habitats and areas under cultivation, if all suitable sleeping sites are destroyed or cleared, then they become locally extinct (Leksono et al. 1997). Further, tarsiers are not found in all secondary habitats (Dagosto & Gebo 1996/1997). In general, densities of T. dentatus become progressively lower with progressively higher levels of disturbance (Merker et al. 2005). Although T. b. saltator can live in secondary habitats with dense undergrowth, they are not found in those that are carefully cleared and managed by humans (Yustian 2007). Compounding all of these problems in some habitats is a lack of enforcement of existing rules designed to protect tarsier habitats (Gursky 2007a).

Threat: Harvesting (hunting/gathering)

Hunting can also be a significant threat to tarsiers. For example, the Siau Island Tarsier (unnamed Tarsius sp.) is hunted as a snack, sometimes eaten 5-10 at a time (Mittermeier et al. 2007). Further, opportunistic hunting of tarsiers occurs on Sulawesi, often utilizing dogs and blowguns (Gursky 2007a).

Threat: Persecution

Tarsiers are sometimes erroneously persecuted by farmers who believe that the tarsiers are eating their crops while in actuality they only eat animal prey, including pests that pose real threats to crops (Leksono et al. 1997; Merker et al. 2005). In fact, tarsiers could potentially act as a natural pesticide (Leksono et al. 1997).

Threat: Pollution

In some areas, the use of agricultural poisons have caused local extinction of tarsiers while in other areas of poison use, if still present, tarsiers show signs of sickness, including sores and low body weight which may be associated with such poisons (Leksono et al. 1997).

Threat: Natural Disasters

Forest fires, partially the result of human action and climate fluctuations, threaten tarsiers and have the potential to decimate entire tarsier populations (Wright 2003).

Threat: Human Disturbance

Human political unrest, especially civil wars in the Philippines and Indonesia have threatened tarsier species, especially those that reside entirely within a single country (all but T. bancanus). This is because protected habitats are often exploited during periods of lawlessness associated with political unrest (Wright 2003).

LINKS TO MORE ABOUT CONSERVATION

CONSERVATION INFORMATION

CONSERVATION NEWS

ORGANIZATIONS INVOLVED IN Tarsius CONSERVATION

Content last modified: December 1, 2010

Written by Kurt Gron. Reviewed by Nanda Grow.

Cite this page as:
Gron KJ. 2010 December 1. Primate Factsheets: Tarsier (Tarsius) Conservation . <http://pin.primate.wisc.edu/factsheets/entry/tarsier/cons>. Accessed 2020 July 9.

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Content last modified: December 1, 2010

IMAGES

Tarsius bancanus
Photo: David Haring

Tarsius dentatus
Photo: Stefan Merker

Tarsius lariang
Photo: Stefan Merker

Tarsius syrichta
Photo: David Haring
Tarsius syrichta
Photo: David Haring
Tarsius syrichta
Photo: David Haring
Tarsius syrichta
Photo: Garrison & Schmidt

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