Greater white-toothed shrew  (Crocidura russula)

Protected under Schedule 6 of the Wildlife and Countryside Act, 1981 (3).

This shrew is one of the 'white-toothed shrews'; it lacks deposition of iron in the enamel of the tips of the teeth as seen in the red-toothed shrews (4). The upper surface of the body is greyish or reddish brown in colour; the underside becomes more of a yellowish grey, and there is no clear demarcation between the two (5). The tail is covered in long whisker-like (2) white hairs (5). Although generally larger in size, this species is very similar in appearance to the lesser white-toothed shrew (Crocidura suaveolens) (2), so much so that the only truly reliable method to distinguish between the two species is by detailed examination of the teeth (5).

This species is one of the commonest shrews in Eurasia (2). It has a broad distribution throughout western and southern Europe (6), including many Mediterranean islands (2), and also occurs in North Africa, (5). In the British Isles, the greater white-toothed shrew occurs on the Channel Islands of Alderney, Guernsey and Herm, where it is thought to have been introduced (4).

Inhabits grassland, hedgerows and woodland, favouring dry ground. In the Channel Islands, it may also be found amongst rocks on the seashore and on grass-covered sand dunes (4). Although it typically occurs at altitudes below 1000m, it has been found at 1600m in the Alps (5). It often occurs close to man, living around outbuildings (5).

This shrew alternates bouts of activity with rest (2) throughout both the day and night (5), but activity peaks at dusk and dawn (5). It feeds on a variety of invertebrates (2), and occasionally takes lizards and small rodents despite its small size (4). They nest under logs and stones or in burrows (2). This species has a greater reproductive output than any of the British red-toothed shrews, producing 4-5 litters a year, each comprising of 2-10 young (6). The young exhibit 'caravanning' behaviour (2); if the nest is disturbed, the female leads the young to a new nest site and the young follow her in a line, each one grasping the tail of the shrew in front by the tail (4). This species is much less aggressive than the red-toothed shrews. Females may even allow her mate to remain in the nest with the offspring, and will leave him with the young as she goes to forage. The male often crouches over the young to shelter them during the female's absence (4).

This species is not threatened at present, although like most shrews it is vulnerable to pesticide use, habitat loss and declines in prey availability (6).

All shrews are protected under the Wildlife and Countryside Act, 1981 (3).

For more on this species see: Shrews of the British Isles (1988), by Sara Churchfield (Shire Publishing Ltd).

1. National Biodiversity Network Species Dictionary (May 2002) http://www.nhm.ac.uk/nbn/
2. Burton, J. A. (1991) Field guide to the mammals of Britain and Europe. Kingfisher Books, London.
3. Morris, P. (1993) A red data book for British mammals. Mammal Society, Bristol.
4. Churchfield, S (1988) Shrews of the British Isles. Shire Natural History, Shire Publications, Aylesbury.
5. IUCN Insectivore, Tree Shrew and Elephant Shrew Specialist Group (ITSES) (August 2002): http://members.vienna.at/shrew/itsesAP95-russula.html#russula
6. Macdonnald, D. W. & Tattersall, F. T. (2001) Britain's mammals- the challenge for conservation. The Wildlife Conservation research Unit, Oxford University. www.wildcru.org