Exilisciurus exilis 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Rodentia Sciuridae

Scientific Name: Exilisciurus exilis (Müller, 1838)
Common Name(s):
English Least Pygmy Squirrel

Assessment Information [top]

Red List Category & Criteria: Data Deficient ver 3.1
Year Published: 2016
Date Assessed: 2016-08-23
Assessor(s): Koprowski, J. & Meijaard, E.
Reviewer(s): Amori, G.
Contributor(s): Duckworth, J.W. & Gumal, M.
Facilitator/Compiler(s): Gerrie, R.

Listed as Data Deficient in view of continuing uncertainties as to its extent of occurrence, status and ecological requirements. It was until recently thought to be endemic to Borneo and restricted to lowland forest. However, a recent unpublished discovery revealed that the species also occurs on Sumatra, where the original type specimen was in fact collected. Whether or not the Sumatran taxon is a close-related but taxonomically distinct species remains to be investigated. On Borneo, the species’ lowland habitat is suffering heavy degradation and the effect on the species is not clear. Further studies are needed to assess its adaptability to oil palm plantations.

Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is endemic to Borneo, although recent surveys suggest that the species range may extend beyond the island of Borneo to Sumatra (E. Meijaard pers. comm). It occurs also on Banggi island (Thorington and Hoffmann 2005).
Countries occurrence:
Brunei Darussalam; Indonesia (Kalimantan); Malaysia (Sabah, Sarawak)
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]


The abundance and population size of this species are not well known. It is perhaps Borneo’s most common squirrel at elevations below 1,000 m asl (Anwarali-Khan et al. 2008, Phillipps and Phillipps 2016).

Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:This diurnal species inhabits predominantly lowlands and lower hills, but has been found up to 1,700 m asl (Thorington et al. 2012). It forages along tree trunks for insects and bark (Thorington et al. 2012).

Threats [top]

Major Threat(s): This species is threatened by the massive habitat conversion of lowland and lower hill forest in Borneo. It is unclear whether the species can use replacement plantations (W. Duckworth et al. pers. comm).

Conservation Actions [top]

Conservation Actions: It occurs in various protected areas but many of these may support only small populations as they may be above this species' main altitudinal range (W. Duckworth et al. pers. comm).

Errata [top]

Errata reason: This errata assessment has been created because the map was accidentally left out of the version published previously.

Citation: Koprowski, J. & Meijaard, E. 2016. Exilisciurus exilis (errata version published in 2017). The IUCN Red List of Threatened Species 2016: e.T8437A115087769. . Downloaded on 21 September 2018.
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