Micaelamys granti 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Rodentia Muridae

Scientific Name: Micaelamys granti (Wroughton, 1908)
Common Name(s):
English Grant's Rock Rat, Grant's Rock Mouse
Aethomys granti (Wroughton, 1908)
Taxonomic Source(s): Monadjem, A., Taylor, P.J., Denys, C. and Cotterill, F.P.D. 2015. Rodents of Sub-Saharan Africa - a biogeographic and taxonomic synthesis. De Gruyter, Berlin/Munich/Boston.
Taxonomic Notes:

Although formerly included in the genus Aethomys, chromosomal, morphological and molecular evidence support the recognition of Micaelamys as a distinct genus (Baker et al. 1988, Russo 2003, Chimimba 2005, Lecompte et al. 2008). Micaelamys granti can be can be distinguished from M. namaquensis on morphological and chromosomal grounds (Visser and Robinson 1986, 1987; Chimimba et al. 1999). In M. namaquensis the tail is relatively longer, the ventral pelage is often pure white, and there are only three pairs of nipples; whereas, in M. granti, the ventral pelage is never pure white (usually grey or greyish), and there are five pairs of nipples (Monadjem et al. 2015).

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2017
Date Assessed: 2017-01-18
Assessor(s): Child, M.F., Avery, M., Palmer, G. & Birss, C.
Reviewer(s): Amori, G.
Contributor(s): Avenant, N., Baxter, R., MacFadyen, D., Monadjem, A., Taylor, P. & Wilson, B.

This species is endemic to the Karoo regions of South Africa and remains Least Concern due to its wide distribution and because it exists in rocky habitat in a generally arid area that is unlikely to be transformed. Thus, there are no major threats that are suspected to be causing population decline. However, it is unknown whether this species can exist in agricultural landscapes and thus local declines are likely as climate change makes rocky habitats more suitable for agricultural expansion (for example, rooibos plantations in the Cedarberg). Field surveys are also required to collate localities where the species is currently present and thus enable the estimation of area of occupancy (AOO). If such data indicate a restricted AOO, this species could qualify for a threatened category given an inferred continuing decline in habitat. This species should be reassessed as new data become available.

Previously published Red List assessments:

Geographic Range [top]

Range Description:

This species is endemic to the Karoo regions of south-central South Africa, south of the Gariep River, where it occupies rocky outcrops in arid or semi-arid landscapes (Monadjem et al. 2015). They are sometimes sympatric with M. namaquensis (for example, Kok et al. 2012). They are confined to the southern and south-eastern areas of the Northern Cape Province, the northern and north-eastern areas of the Western Cape Province and the north-western regions of the Eastern Cape Province (Skinner and Chimimba 2005). Based primarily on museum records, it has an estimated extent of occurrence of 236,027 km². There are very few recent (post-2000) records available. For example, no new records were discovered for this species from Barn Owl (Tyto alba) analysis in either the Western or Northern Cape provinces (Avery et al. 2005, Avery and Avery 2011), although they are perhaps not preyed upon extensively by Barn Owls. Recently, however, Kok et al. (2012) confirmed its presence in the Sneeuberg Mountain Complex (all sites above 1,700 m asl) of the Eastern Cape Province (sampling conducted between 2009 and 2010), where they occurred at low densities in the Sneeuberg Nature Reserve and Asante Sana Nature Reserve but not the Mountain Zebra National Park. It is uncertain whether the overall lack of recent records is due to lack of current field surveys (low search effort) or a genuine loss in area of occupancy from anthropogenic transformation of habitat. Further vetting of museum specimens is also required.

Countries occurrence:
South Africa
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]


The abundance and population size is not known. However, they are certainly rarer and far less abundant than M. namaquensis. For example, they comprised only 8.9% of total Micaelamys captures (N = 90 specimens) at three sites in the Sneeuberg Mountains, Eastern Cape Province (Kok et al. 2012). Its habitat currently does not appear to be extensively fragmented by human activities and thus the population is unlikely to be declining rapidly, but further field studies to assess occupancy and monitor the impacts of agricultural expansion into its habitats are needed to evaluate population trends. The lack of significant differences in cranial size across its geographical range suggests at least some connectivity between no subpopulations and does not support any subspecies delineation (Chimimba et al. 1998).

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

Habitat and Ecology [top]

Habitat and Ecology:

This species occurs in shrubland and rocky areas on mountain slopes. It is not known if it can persist in disturbed or modified habitats, such as agricultural landscapes. It is likely its biology and ecology is similar to M. namaquensis.

Potential flagship species of the Karoo for biodiversity stewardship agreements.

Generation Length (years):1-2

Use and Trade [top]

Use and Trade:

This species is not traded or utilised in any form.

Threats [top]

Major Threat(s):

There are no known major threats as its habitat is largely intact and inaccessible. However, although, no threats were listed for this species in the previous assessment (Friedmann and Daly 2004), habitat loss from new forms of agricultural expansion may represent an emerging threat to this species. For example, the clearing of vegetation patches in rocky areas in the Cederberg region for rooibos tea plantations may lead to localised declines.

Habitat is stable with localised declines. The majority of the habitat will likely remain unchanged as it lives in rocky areas inaccessible to transformation. However, climate change is projected to make higher-altitude habitats more suitable for agriculture. For example, the suitability of upslope habitats for viticulture is projected to increase the footprint of winelands by 14% by 2050 (Hannah et al. 2013). Such trends in transformation of mid and upper slopes should be monitored.

Conservation Actions [top]

Conservation Actions:

We assume this species occurs in several protected areas within its range; for example, along the Cape Fold Mountain belt. However, their current presence has recently only been confirmed for Sneeuberg Nature Reserve and Asante Sana Nature Reserve in the Eastern Cape Province (Kok et al. 2012).

No specific conservation interventions are necessary but it will benefit from protected area expansion to connect habitat and thus increase resilience to climate change and the effects of agricultural expansion onto higher elevations. Biodiversity stewardship schemes should also be pursued to achieve this, particularly if the landowner possesses pristine rocky outcrops and shrublands.

Recommendations for land managers and practitioners:
Conserve / restore buffer strips of natural vegetation around rocky outcrops

Research priorities:

  1.   Field surveys are needed to collate current distribution data and thus estimate area of occupancy
  2.   There is no information on their habits, food or reproduction. Thus, basic ecological and biological information is required.

Encouraged citizen actions:
Landowners and city planners can conserve natural vegetation around rocky outcrops.

Citation: Child, M.F., Avery, M., Palmer, G. & Birss, C. 2017. Micaelamys granti. The IUCN Red List of Threatened Species 2017: e.T570A110017075. . Downloaded on 20 September 2017.
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