Crocidura russula
white-toothed shrew

Greater white-toothed shrews are found from southwestern Europe to northern Africa. This range includes some Mediterranean and Atlantic islands. Greater white-toothed shrews are widespread throughout their range. ("Arkive", 2003; Balloux, et al., 1998)

Greater white-toothed shrews favor temperate regions with many insects. They can be found in a wide variety of habitats, including grasslands, woodlands, hedgerows, and agricultural areas. Living near farms and gardens helps them prepare for colder seasons (Duarte et al., 2003). Greater white-toothed shrews prefer dry soils. On islands they are found in grassy areas and near rocks on shorelines. They tend to nest under stones, logs, or in abandoned burrows. Greater white-toothed shrews are typically found at elevations below 1000 m (“Arkive”, 2003). ("Arkive", 2003; Duarte, et al., 2003)

Greater white-toothed shrews are medium-sized shrews weighing from 11 to 14 grams (Balloux, Goudet and Perrin, 1998; Duarte et al., 2003). Head and body length is 6 to 9 cm and tail length is generally 3 to 4.6 cm. The dorsal fur is reddish brown or grayish while the belly is yellowish grey. This species is said to be very similar to lesser white-toothed shrews (Crocidura suaveolens), but is generally larger. ("Arkive", 2003; Balloux, et al., 1998; Duarte, et al., 2003)

Greater white-toothed shrews are monogamous and exhibit female-biased dispersal. This mating system is rare for mammals. These monogamous shrews defend a common breeding territory (Balloux, Goudet and Perrin, 1998). Greater white-toothed shrews have a single breeding season and fertilization occurs directly after parturition (Duarte et al., 2003). Females from the first litter disperse prior to mating to avoid inbreeding. The litters born later do not reach maturity until the following year so by that time their fathers are usually dead. These females still, however, run the risk of mating with other relatives such as a brother or cousin, making potential inbreeding a problem (Balloux, Goudet and Perrin, 1998). (Balloux, et al., 1998; Duarte, et al., 2003)

Greater white-toothed shrews breed from March to September during which time they produce up to four litters. These four litters can contain anywhere from 2 to 10 young. This species reaches sexual maturity fairly quickly and they have short lifespans. As mentioned previously, natal dispersal is generally only seen in weanlings from the first litter of the season. All later litters usually do not reproduce until the following year so they remain near or in the parental territory. Even though females disperse, about half of them remain locally and most of the males stay close as well increasing the risk of inbreeding (Duarte et al., 2003). (Duarte, et al., 2003)

Both female and male greater white-toothed shrews care for their young. They both defend their territory and also forage for food (Bouteiller-Reuter and Perrin, 2005). Young are weaned after 13 to 20 days, at which point they are independent. Sexual maturity occurs soon after that. ("Arkive", 2003; Bouteiller-Reuter and Perrin, 2005)

Greater white-toothed shrews are relatively short lived. Lifespan is only about 18 months in the wild. Under laboratory conditions, however, lifespan can increase to about 30 months (Magnanou et al., 2009). (Magnanou, et al., 2009)

Greater white-toothed shrews are semi-social. They live in close proximity to one another. In the winter they share nests when they rest and enter torpor. Mated pairs also defend their territories together (Balloux, Goudet and Perrin, 1998). Sometimes females even allow males to stay in the nest with the young to protect them (“Arkive”, 2003). Greater white-toothed shrews are monogamous and exhibit female-biased dispersal, which is uncommon in mammals. One of the reasons for female dispersal is to avoid inbreeding. This dispersal may also be caused by local infiltration and migration to empty breeding sites (Duarte et al., 2003). ("Arkive", 2003; Balloux, et al., 1998; Duarte, et al., 2003)

Although home range sizes are not reported, greater white-toothed shrews likely have rather small home ranges because of their small size.

Greater white-toothed shrews, as well as other shrews, can be fairly vocal animals. It is thought that they may communicate with a primitive form of echolocation. They produce a twittering call, which is a high pitched laryngeal call, and also use echoes to interpret their environment. These techniques, along with the use of their vibrissae, are used to find their way around (Siemers et al., 2009). Modes of communication have not been reported, but vocalizations and tactile and chemical cues are likely to be used. (Siemers, et al., 2009)

Greater white-toothed shrews are insectivorous mammals (Duarte et al., 2003). They feed on invertebrates and may occasionally eat the young of small mammals or small lizards (“Arkive”, 2003). This species prefers areas that are temperate and rich with insects (Balloux, Goudet and Perrin, 1998). ("Arkive", 2003; Balloux, et al., 1998; Duarte, et al., 2003)

The main predators of greater white-toothed shrews are likely to be owls, snakes, and small, carnivorous mammals such as weasels. No specific observations of predators are reported in the literature, however (Balloux, Goudet and Perrin, 1998). These shrews, like other shrews, remain mainly under cover of vegetation or leaf litter when active and are cryptically colored to avoid predation. (Balloux, et al., 1998)

Greater white-toothed shrews are preyed on by many animals. An abundance of these shrews may lead to a decline in some small species such as their insect prey and small mammals, such as pygmy shrews (Suncus), that they prey on (Wiley-Blackwell, 2008). (Wiley-Blackwell, 2008)

There are no known positive effects of C. russula on humans.

There are no known adverse effects of C. russula on humans.

Greater white-toothed shrews are not threatened and has no special conservation status. They are listed as a species of least concern in the IUCN Red List of Threatened Species. They are susceptible to habitat loss, loss of prey availability, and harmful pesticides but populations are widespread and they are considered common (“Arkive”, 2003). ("Arkive", 2003; "The ICUN Red List of Threatened Species", 2009)

Of any mammal genus, Crocidura contains the largest number of species with 175. ("The ICUN Red List of Threatened Species", 2009; "Wikipedia", 2009)