Tarsius bancanus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Primates Tarsiidae

Scientific Name: Tarsius bancanus Horsfield, 1821
Infra-specific Taxa Assessed:
Common Name(s):
English Horsfield’s Tarsier, Horsfield's Tarsier, Western Tarsier
French Tarsier De Bornéo
Tarsius natunensis Chasen, 1940
Taxonomic Notes: The taxonomy of this species is disputed, with some subspecies considered dubious (Brandon-Jones et al. 2004). Indeed, little work has been done on T. bancanus in the past 20 years and a taxonomic revision based upon intensive and systematic field surveys is overdue. Until more definitive evidence is available, and given that these allopatric populations have already been named as separate taxa, it is more conservative to treat them as distinct than not.

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2cd ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor(s): Shekelle, M. & Yustian, I.
Reviewer(s): Mittermeier, R.A., Rylands, A.B. (Primate Red List Authority) & Hoffmann, M. (Global Mammal Assessment Team)
Over the last 20 years (approximately three generations), at least 30% of the habitat has been lost, qualifying this species as Vulnerable where population reduction is inferred based on habitat loss. In addition, levels of exploitation can be regionally high for the pet trade, yet impacts at the population level are unknown. Further research is needed (taxonomic, threat and ecological) in order to further assess this species.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is found in Brunei, Indonesia (Bangka, Belitung, Karimata, southeastern Sumatra, Serasen in the South Natuna Islands, and Kalimantan Borneo), and Malaysia (Sabah and Sarawak) (Groves 2005). The distribution in Sumatra is unknown but is thought to be delimited by the Musi River.

Tarsius bancanus saltator
Confined to the island of Belitung (Billiton), Indonesia.

Tarsius bancanus natunensis
Confined to Serasan (Sirhassen) in the South Natuna Islands, and possibly nearby Subi Island, Indonesia.

Tarsius bancanus borneanus
Occurs in Brunei, Indonesia (Kalimantan Borneo and Karimata Islands) and Malaysia (Sabah and Sarawak Borneo) and on the island of Karimata (Indonesia).

Tarsius bancanus bancanus
Occurs in southeastern Sumatra and the island of Bangka, Indonesia.
Countries occurrence:
Brunei Darussalam; Indonesia; Malaysia
Additional data:
Upper elevation limit (metres):1200
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Density has been variously calculated at 80 animals/km2 in Sarawak (Niemitz 1979, 1984), 15-20 individuals/km2 in Sabah (Crompton and Andau 1986, 1987), and 19-20 individuals/km2 in Belitung (I. Yustian pers. comm.). Based on satellite studies of the extent of available habitat on Belitung Island, Yustian (2006) estimated a total population for T. b. saltator of 29,440 (Yustian unpubl. data).
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:This species can live in both primary and secondary forest, as well as along the coasts or on the edge of plantations (Niemitz 1979). This is often described as a lowland species, most common below 100 m elevation; however, there is at least one record from 1,200 m from the Bukit Baka-Bukit Raya National Park in western Kalimantan (Gorog and Sinaga in press).

The species is 100% carnivorous, eating mainly insects (including beetles, grasshoppers, cockroaches, butterflies, moths, praying mantis, ants, phasmids, and cicadas), but also small vertebrates (including bats, snakes, and birds) (Niemitz 1979). These animals are nocturnal and exhibit adaptations for vertical clinging and leaping modes of locomotion and prey capture (Roberts 1994). They spend a majority of their time below 2 meters off the ground and only 5% above 3 meters (Niemitz 1979, 1984; Crompton and Andau 1986, 1987).

Threats [top]

Major Threat(s): The principle threat is habitat loss due to forest conversion, especially due to expanding oil palm plantations, fires and logging. The species is collected for the illegal pet trade, particularly, it is thought, in the vicinity of Lampung and Way Kambas National Park. It is wrongly considered a pest to agricultural crops, and can suffer, directly and indirectly, from contamination from agricultural pesticides.

Conservation Actions [top]

Conservation Actions: The species is protected by law in Indonesia and in Malaysia, and is listed in CITES Appendix II.

T. b. bancanus occurs in a few protected areas, such as Bukit Barisan Selatan National Park, Kerinci Seblat National Park, Way Kambas National Park (Indonesia) (M. Richardson pers. comm.); T. b. borneanus occurs in several protected areas, including Tasek Merimbun Sanctuary (Brunei); Bukit Baka Bukit Raya National Park, Kayan Mentarang National Park (Indonesia); Bako National Park, Gunung Malu National Park, Kinabalu National Park, Sapagaya Forest Reserve, Semengo Forest Reserve, Sepilok Forest Reserve (Malaysia) (M. Richardson pers. comm.); while
T. b. saltator and T. b. natunensis do not occur in any protected areas.

Citation: Shekelle, M. & Yustian, I. 2008. Tarsius bancanus. The IUCN Red List of Threatened Species 2008: e.T21488A9286601. . Downloaded on 25 May 2018.
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