African giant shrew (Crocidura olivieri)
|Size||Head-body length: 12 cm (2)|
Tail length: 8 cm (2)
|Weight||31 - 37 g (2)|
Classified as Least Concern (LC) on the IUCN Red List (1).
The aptly named African giant shrew is one of the largest shrews in the world (3). Like most shrews, it has a mouse- or rat-shaped body with a pointed snout, small, beady eyes and sharp, even-sized teeth (unlike rodents, which possess characteristic large incisors) (4). Most individuals are covered in short, brown fur, although colour can vary considerably, from black to grey or fawn (2). The fur on the back is a darker shade, while the underside is usually lighter (2). Until recently, the black forms were thought to be a different species, and even a different genus; however, recent DNA testing has shown both the black, brown and other forms to be of the same species (3). The African giant shrew has a long tail, sometimes measuring as much as 50 percent of the body length (4), which is mostly hairless, with just a few long hairs along its length (2). Male and female African giant shrews are identical in appearance (4).
In sub-Saharan Africa, the African giant shrew is a very common mammal, with a range stretching from the east to west coasts of the continent (1). The shrew’s range reaches as far south as Botswana and as far north as Mali, although there is also a separate, unconnected population further north, along the Nile Valley in Egypt (1).
The African giant shrew is adapted to a wide variety of habitats, such as savanna, steppe, woodland and marsh (3). In southern parts of its range, and in the separate population along the Nile Valley, the African giant shrew is generally found in moist habitats, such as streams, and human-created environments, such as canal embankments, fields and gardens (1).This species has been recorded at altitudes of up to 2,680 metres (in Mgahinga National Park in Uganda) (1).
A rarely studied species, relatively little is known about the habits of the African giant shrew. It is predominantly a carnivore, feeding on insects and other invertebrates such as slugs and snails. Like all shrews, it has a voracious appetite and fast metabolism, meaning it needs to eat a large amount every day. It alternates periods of activity and rest throughout the day and night (2), but is most active at dusk and dawn (4).
The African giant shrew is believed to be territorial and largely solitary (2), although mating pairs form during the summer months, from August to April (4). A litter of between one and seven naked and helpless young are born after a gestation period of 28 to 36 days (4). Like many other shrews, this species performs what is known as ‘caravanning’; if the nest becomes unsafe or is disturbed, the mother will move the young to a different location by means of a walking ‘caravan’, with the mother at the front and the young following, each gripping onto the fur of the one in front with its teeth (4). There is no reliable data on life expectancy, but an individual from this genus lived for four years in captivity (5).
As with many animals, habitat loss and habitat fragmentation are considered to be the main threats to the African giant shrew, although the precise effects on shrew populations long-term remains unclear (6). Loss of prey, as a result of habitat loss, is also an issue. Like similar species of shrew, the African giant shrew is thought to be affected by pesticides in agricultural areas, either through direct contact or by consuming contaminated food (7).
As the African giant shrew is not currently considered to be at risk of extinction (1), there are no known conservation measures currently in place for this species. However, the African giant shrewhas been recorded in many protected areas, including the national parks of Bwindi-Impenetrable, Rwenzori, and Mgahinga in Uganda and the Kibira National Park in Burundi (1).
Checked (24/08/10) by Dr Francis Gilbert, Associate Professor, University of Nottingham.
- Carnivore: an organism that feeds on flesh.
- Genus: a category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.
- Gestation: the state of being pregnant; the period from conception to birth.
- Invertebrates: animals with no backbone, such as insects, worms, and spiders.
- Metabolism: the total of all the chemical reactions that take place in an organism, in order to produce energy and the basic materials needed for important life processes. The speed at which an organism carries out these processes is called its metabolic rate.
- Steppe: natural grassland with low rainfall. In Africa this lies in the transition zone between savanna and severe desert.
- Territorial: an animal that occupies and defends an area.
IUCN Red List (April, 2010)
- Stuart, C. and Stuart, T. (2001) Field Guide to Mammals of Southern Africa. Struik Publishers, Cape Town.
- Dubeya, S., Antonina, M., Denys, C. and Vogela, P. (2007) Use of phylogeny to resolve the taxonomy of the widespread and highly polymorphic African giant shrews (Crocidura olivieri group, Crocidurinae, Mammalia). Zoology, 110: 48-57.
- Mills, G. and Hes, L. (1997) The Complete Book of Southern African Mammals. Struik Publishers, Cape Town.
- Nowak, R.M. (1999) Walker's Mammals of the World. The Johns Hopkins University Press, Baltimore, Maryland.
- Mortelliti, A. and Boitani, L. (2009) Distribution and coexistence of shrews in patchy landscapes: A field test of multiple hypotheses. Acta Oecologica, 35: 797–804.
- Macdonald, D. (2001) The New Encyclopedia of Mammals. Oxford University Press, Oxford.