Overview

Crocidura cyanea – (Duvernoy, 1838)

ANIMALIA – CHORDATA – MAMMALIA – EULIPOTYPHLA – SORICIDAE – Crocidura – cyanea 

Common Names: Reddish-grey Musk Shrew (English), Rooigrysskeerbek (Afrikaans)

Synonyms: No Synonyms 

Taxonomic Note:
There are nine subspecies recognised (Heim de Balsac & Meester 1977), of which two occur within the assessment region: C. c. cyanea from northern Namibia to the Western Cape and Free State Provinces as well as Lesotho, and C. c. infumata from parts of the Western and Eastern Cape Provinces northwards to the KwaZulu-Natal, North West, Gauteng, Limpopo, Mpumalanga Provinces, as well as Zimbabwe, northern Botswana and Mozambique. Further research is needed to resolve the taxonomy of this species complex. 

Red List Status: LC – Least Concern, (IUCN version 3.1) 

Assessment Information

Assessors: Russo, I.M.¹, da Silva, J. M.²

Reviewer: Erusan, R.³

Institutions:¹Cardiff University,²South African National Biodiversity Institute, ³South African National Parks 

Previous Assessors: Taylor, P., Baxter, R. & Monadjem, A.,  

Previous Reviewers: Child, M.F. & Harvey, J. 

Previous Contributors: Avery, M., MacFadyen, D., Avenant, N., Wilson, B. & Palmer, G. 

Assessment Rationale 

This species is widely distributed within the assessment region and occurs in many protected areas and can survive in multiple habitat types including agricultural landscapes and gardens. Although commonly encountered, the species occurs at low densities. As there are no major threats identified, there is no reason to suspect a net population decline, but local declines are likely in areas that are overgrazed or where pesticides are used. The species is considered as Least Concern. Further surveys and research should focus on vetting existing museum records as many have been misidentified as C. silacea and vice versa, leading to inaccuracies in the distribution of these species. Key interventions include protected area expansion of moist grassland habitats, as well as incentivising landowners to sustain natural vegetation around wetlands and to keep livestock or wildlife at ecological carrying capacity to avoid overgrazing.

Regional population effects: This species is too small to disperse over long distances, so no significant rescue effects are possible even though habitats are presumably connected across regions. 

Reasons for Change 

Reason(s) for Change in Red List Category from the Previous Assessment: No change 

Red List Index 

Red List Index: No change 

Recommended citation: Russo IM da Silva JM. 2025. A conservation assessment of Crocidura cyanea. In Patel T, Smith C, Roxburgh L, da Silva JM & Raimondo D, editors. The Red List of Mammals of South Africa, Eswatini and Lesotho. South African National Biodiversity Institute and Endangered Wildlife Trust, South Africa.

Regional Distribution and occurrence

Geographic Range 

This species has a wide distribution within the assessment region and southern Africa, occurring in Namibia (but not on the coast), north-eastern Botswana, Zimbabwe and parts of Mozambique (Skinner and Chimimba 2005). Within the assessment region, it is widespread throughout all provinces. Although previously  not recorded from the middle and northern regions of the Northern Cape Province (Friedmann and Daly 2004), new data from Barn Owl (Tyto alba) pellets extends the distribution of the species to areas such as Benfontein Game Farm, Doornkloof Nature Reserve, Driekoppen and Wildflower Reserve (Avery and Avery 2011) and Golden Gate highlands National Park in the Free State. In Eswatini, they are common in the Highveld, Middleveld and Lubombo regions (Monadjem 1998), and occur in Lesotho around the Mahlanapeng and Sehonghong regions (Lynch 1994).

Existing museum records for all Crocidura species including this species and C. silacea need to be exhaustively vetted as C. cyanea and C. silacea are difficult to distinguish (Taylor and Contrafatto 1996). Misidentifications may have led to errors inspecies distribution maps. Similarly, the most recent confirmed museum record from the North West Province was collected from Vaalkop in 1989 but many existing specimens may belong to this species (Power 2014). 

Elevation / Depth / Depth Zones 

Elevation Lower Limit (in metres above sea level): 0 

Elevation Upper Limit (in metres above sea level): 2000 

Depth Lower Limit (in metres below sea level): (Not specified) 

Depth Upper Limit (in metres below sea level): (Not specified) 

Depth Zone: (Not specified) 

Map

Figure 1. Distribution records for Reddish-grey Musk Shrew (Crocidura cyanea) within the assessment region (South Africa, Eswatini and Lesotho). Note that distribution data is obtained from multiple sources and records have not all been individually verified.

Biogeographic Realms 

Biogeographic Realm: Afrotropical 

Occurrence 

Countries of Occurrence 

Large Marine Ecosystems (LME) Occurrence 

Large Marine Ecosystems: (Not specified) 

FAO Area Occurrence 

FAO Marine Areas: (Not specified) 

Climate change

This species may be part of a suite of species that will display a general decline with grassland and fynbos contraction due to climate change (Taylor et al. 2016). Similarly, the western population may suffer significant range contractions and shift to the east as conditions become increasingly arid (Erasmus et al. 2002). 

Population Information

This species is widespread but exists at low density although it can be locally abundant. The species is often trap shy (Jooste and Palmer 1982). It is uncommon but regularly recorded in fynbos. In Rolfontein Nature Reserve, Northern Cape Province, this species was the only shrew species sampled but occurred at low density: 27 individuals compared to 648 Rhabdomys pumilio (Jooste and Palmer 1982). It is one of the more commonly encountered shrews in Eswatini and parts of the north-eastern Kwazulu-Natal Province (Monadjem 1998, J. Harvey unpubl. data). It can be very common in gardens and houses due to compost heaps. 

Population Information 

Current population trend: Stable   

Number of mature individuals in population: Unknown  

Number of mature individuals in largest subpopulation: Unknown  

Number of subpopulations: Unknown  

Severely fragmented: No. Can occur in multiple habitats, including gardens and transformed landscapes. 

Extreme fluctuations in the number of subpopulations: (Not specified) 

Continuing decline in number of subpopulations: (Not specified) 

All individuals in one subpopulation: (Not specified)) 

Quantitative Analysis 

Probability of extinction in the wild within 3 generations or 10 years, whichever is longer, maximum 100 years: (Not specified) 

Probability of extinction in the wild within 5 generations or 20 years, whichever is longer, maximum 100 years: (Not specified) 

Probability of extinction in the wild within 100 years: (Not specified) 

Population Genetics

While the species has been investigated in a phylogenetic context (Matamba et al. 2020), no population genetic studies has been conducted on this species. However, given that it is considered to be widespread throughout all provinces (see Geographic Distribution section) it is possible the species exists as a single metapopulation within the region with one migrant per generation allowing for sufficient gene flow. This should be confirmed using a finescale population genetic approach.  Given the absence of population size data, it is not possible to estimate effective population size. 

Habitats and ecology

It often occurs in relatively dry terrain compared to other shrews, and has been collected from  rocky habitats, dense scrub and grass, montane forest moist habitats, hedges around farmlands, degraded areas and gardens (Meester 1963, Rautenbach 1982, Taylor 1998). In the KwaZulu-Natal Province, it has been found in moist grassy habitats bordering reedbeds, drier bushveld, open grassland, coastal forest (J Harvey pers. obs. 2015) and gardens (Taylor 1998). In the western parts of the country, it has been collected from scrub on Kalahari sand and reedbeds around waterholes (Skinner and Chimimba 2005), and it occurs on karroid scrub and fynbos in rocky areas. In Rolfontein Nature Reserve, Northern Cape Province, it occurred in seven of the eleven vegetation communities, but was most abundant in the Mountain Bristle Grass (Setaria lindenbergiana; Jooste and Palmer 1982). This species has a wide habitat tolerance although it prefers areas with deep leaf litter, moist soil and ground level vegetation (Dickman 1995). Similarly, in Swaziland, it has a wide habitat tolerance but is mainly associated with grasslands overlaying rocky terrain (Monadjem 1997). Interestingly, in Namibia, a population has been found inhabiting a cave, where they feed on cave invertebrates and possibly dead bats (Marais and Irish 1990). They are sporadically active throughout the day and night and are insectivorous with a high proportion of Isoptera in their diet (Dickman 1995).

This species is almost undiscernible from its sibling species C. silacea, differing only in cranial and dental characters (Meester et al. 1986, Taylor et al. 1994, Taylor and Contrafatto 1996).

Ecosystem and cultural services: An important prey species for owls (e.g., Perrin 1982). 

IUCN Habitats Classification Scheme 

Life History 

Generation Length: (Not specified) 

Age at Maturity: Female or unspecified: (Not specified) 

Age at Maturity: Male: (Not specified) 

Size at Maturity (in cms): Female: (Not specified) 

Size at Maturity (in cms): Male: (Not specified) 

Longevity: (Not specified) 

Average Reproductive Age: (Not specified) 

Maximum Size (in cms): (Not specified) 

Size at Birth (in cms): (Not specified) 

Gestation Time: (Not specified) 

Reproductive Periodicity: (Not specified) 

Average Annual Fecundity or Litter Size: (Not specified) 

Natural Mortality: (Not specified) 

Breeding Strategy 

Does the species lay eggs? No

Does the species give birth to live young? No

Does the species exhibit parthenogenesis? No

Does the species have a free-living larval stage? No

Does the species require water for breeding? No

Movement Patterns 

Movement Patterns: (Not specified) 

Congregatory: (Not specified) 

Systems 

System: Terrestrial 

General Use and Trade Information

There is no known subsistence or commercial use of this species. 

Local Livelihood: (Not specified) 

National Commercial Value: (Not specified) 

International Commercial Value: (Not specified) 

End Use: (Not specified) 

Is there harvest from captive/cultivated sources of this species? (Not specified) 

Harvest Trend Comments: (Not specified) 

Threats

No severe threats are currently known to affect this species but the main threat to shrews in general is the loss or degradation of moist, productive areas, such as wetlands and rank grasslands within suitable habitat. The two main drivers behind this are abstraction of surface water and draining of wetlands through industrial and residential expansion, and overgrazing of moist grasslands, which leads to the loss of ground cover and decreases small mammal diversity and abundance (Bowland and Perrin 1989, 1993). Overgrazing is particularly threatening for this species as it relies on medium to tall grass cover. Suppression of natural ecosystem processes, such as severe fire, can also lead to habitat degradation through bush encroachment or loss of plant diversity through alien invasives, and is suspected to be increasing with human settlement expansion. As this species does occur in agricultural landscapes, the use of pesticides is a threat as it is vulnerable to biomagnification due to its predominantly insectivorous diet. There are also clear overlaps and synergistic effects between these threats. A continuing population decline based on loss of natural habitat is inferred. 

Conservation

This species is found in several protected areas across its range. It has been widely recorded in protected areas in the KwaZulu-Natal Province (Taylor 1998) and Ferreira and Avenant (2003) recorded it in Tussen-die-Riviere Nature Reserve and Golden Gate Highlands National Park in Free State Province. Although no direct conservation interventions are necessary, protecting and restoring suitable habitat such as moist grassland and fynbos patches will benefit this species. Biodiversity stewardship schemes should be promoted to conserve such patches. Protecting these habitats may create dispersal corridors between patches that will restore habitat connectivity. Landowners and managers should be educated, encouraged and incentivised to conserve the habitats on which shrews and other small mammals depend. Retaining ground cover is the most important management tool to increase small mammal diversity and abundance. This can be achieved through reduced grazing pressure (Bowland and Perrin 1989), or by maintaining buffer strips of natural vegetation around wetlands (Driver et al. 2012). Small mammal diversity and abundance is also higher in more complex or heterogeneous landscapes where periodic burning is an important tool to achieve this (Bowland and Perrin 1993). Removing alien vegetation from watersheds, watercourses and wetlands is also an important intervention to improve flow and water quality, and thus habitat quality for shrews. Education and awareness campaigns should be employed to teach landowners and local communities about the importance of conserving wetlands and moist grasslands. Farmers should be encouraged to reduce their use of pesticides and use biological control instead.

Recommendations for land managers and practitioners: 

• Landowners and communities should be incentivised to stock livestock or wildlife at ecological carrying capacity to avoid overgrazing and to maintain a buffer of natural vegetation around wetlands.  

• Enforce regulations on developments that could potentially impact on the habitat integrity of grasslands and wetlands. 

Research priorities: 

• Additional field surveys are needed to clarify and confirm the taxonomy and the distribution of this species. 

• The effects of climate change on the distribution and abundance of the species should be modelled. 

• Museum records must be vetted to refine the distribution map. 

Encouraged citizen actions: 

• Citizens are requested to submit any shrews killed by cats or drowned in pools to a museum or a provincial conservation authority for identification to enhance our knowledge of shrew distributions (carcasses can be placed in a ziplock bag and frozen with the locality recorded).  

• Practice indigenous gardening to sustain small mammals. 

Bibliography

Avery, D.M. and Avery, G. 2011. Micromammals in the Northern Cape Province of South Africa, past and present. African Natural History 7: 9-39. 

Bowland, A.E. and Perrin, M.R. 1989. The effect of overgrazing on the small mammals in Umfolozi Game Reserve. Zeitschrift für Säugetierkunde 54: 251–260. 

Bowland, J.M. and Perrin, M.E. 1993. Wetlands as reservoirs of small-mammal populations in the Natal Drakensberg. South African Journal of Wildlife Research 23: 39–43. 

Dickman CR. 1995. Diets and habitat preferences of three species of crocidurine shrews in arid southern Africa. Journal of Zoology 237: 499-514. 

Driver, A., Sink, K.J., Nel, J.N., Holness, S., Van Niekerk, L., Daniels, F., Jonas, Z., Majiedt, P.A., Harris, L. and Maze, K. 2012. National Biodiversity Assessment 2011: An assessment of South Africa’s biodiversity and ecosystems. Synthesis Report. South African National Biodiversity Institute and Department of Environmental Affairs, Pretoria, South Africa. 

Erasmus, B.F.N., van Jaarsveld, A.S., Chown, S.L., Kshatriya, M. and Wessels, K.J. 2002. Vulnerability of South African animal taxa to climate change. Global Change Biology 8: 679-693. 

Ferreira, S.M. and Avenant, N.L. 2003. Modelling the effects of trap-spacing on small mammal community descriptors in grasslands at Tussen-die-Riviere Nature Reserve, Free State Province, South Africa. Navorsinge van die Nasionale Museum, Bloemfontein 19: 21-30. 

Friedmann, Y. and Daly, B. 2004. Red Data Book of the Mammals of South Africa: A Conservation Assessment. Conservation Breeding Specialist Group (SSC/IUCN) and Endangered Wildlife Trust, Parkview, South Africa. 

Heim de Balsac, H. and Meester, J. 1977. Order Insectivora. In: J. Meester and H.W. Setzer (eds), The Mammals of Africa: An Identification Manual, pp. 1-29. Smithsonian Institution Press, Washington, D. C., USA. 

Jooste JF, Palmer NG. 1982. The distribution and habitat preference of some small mammals in the Rolfontein Nature Reserve. South African Journal of Wildlife Research 12: 26-35. 

Lynch, C.D. 1994. The mammals of Lesotho. Navorsinge van die Nasionale Museum Bloemfontein 10(4): 177-241. 

Marais, E. and Irish, J. 1990. A cavernicolous population of Crocidura cyanea (Duvernoy) (Insectivora: Soricidae). Cimbebasia 12: 169-170. 

Meester, J. 1963. A systematic revision of the shrew genus Crocidura in Southern Africa. Transvaal Museum Memoir 13: 1-127. 

Meester, J.A.J., Rautenbach, I.L., Dippenaar, N.J. and Baker, C.M. 1986. Classification of Southern African Mammals. Monograph number 5. Transvaal Museum , Pretoria, South Africa. 

Monadjem A. 1997. Habitat preferences and biomasses of small mammals in Swaziland. African Journal of Ecology 35: 64-72. 

Monadjem A. 1998. The mammals of Swaziland. Conservation Trust of Swaziland and Big Games Parks, Mbabane, Swaziland. 

Perrin MR. 1982. Prey Specificity of the Barn Owl, Tyto alba, in the Great Fish River Valley of the Eastern Cape Province. South African Journal of Wildlife Research 12: 14-25. 

Power, R.J. 2014. The distribution and status of mammals in the North West Province. Department of Economic Development, Environment, Conservation & Tourism, North West Provincial Government, Mahikeng. 

Rautenbach, I. L. 1982. Mammals of the Transvaal. Ecoplan monograph, N.S. Supplemento 1: 111-211. 

Skinner, J.D. and Chimimba, C.T. (eds). 2005. The Mammals of the Southern African Subregion. Cambridge University Press, United Kingdom, Cambridge. 

Taylor PJ, Contrafatto G. 1996. Mandible shape and size in three species of small musk shrews (Crocidura Wagler, 1832) from southern Africa. Mammalia 60: 753-766. 

Taylor, P. 1998. The Smaller Mammals of KwaZulu-Natal. University of Natal Press, Pietermaritzburg, South Africa. 

Taylor, P.J., Nengovhela, A., Linden, J. and Baxter, R.M. 2016. Past, present, and future distribution of Afromontane rodents (Muridae: Otomys) reflect climate-change predicted biome changes. Mammalia 80: 359–375. 

Taylor, P.J., Richardson, E.J., Meester, J. and Wingate, L. 1994. New distribution records for six small mammal species in Natal, with notes on their taxonomy and ecology. Durban Museum Novitates 19: 59-66.