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).
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
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.
Known Predators:
Anti-predator Adaptations: cryptic
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.
Range mass: 11 to 14 g.
Range length: 6 to 9 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike
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).
Typical lifespan
Status: wild: 18 (high) months.
Average lifespan
Status: wild: 1 months.
Typical lifespan
Status: captivity: 30 (high) months.
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).
Range elevation: 1600 (high) m.
Average elevation: 1000 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: savanna or grassland ; forest ; scrub forest
Other Habitat Features: agricultural
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.
Biogeographic Regions: palearctic (Native )
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).
Animal Foods: mammals; reptiles; insects
Primary Diet: carnivore (Insectivore )
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).
There are no known positive effects of C. russula on humans.
Positive Impacts: research and education
There are no known adverse effects of C. russula on humans.
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.
Communication Channels: tactile ; acoustic ; chemical
Perception Channels: visual ; tactile ; acoustic ; ultrasound ; chemical
Of any mammal genus, Crocidura contains the largest number of species with 175.
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).
Mating System: monogamous
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).
Breeding interval: Greater white-toothed shrews have a single breeding season in which they can have up to 4 litters.
Breeding season: Greater white-toothed shrews breed from March to September.
Range number of offspring: 2 to 10.
Range weaning age: 13 to 20 days.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
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.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female)
The greater white-toothed shrew (Crocidura russula) is a small insectivorous mammal[3] found in Europe and North Africa. It is the most common of the white-toothed shrews. This species is found along the Mediterranean, Netherlands, Belgium, Ireland, Germany and Portugal;[4] in addition, the Osorio shrew of the Canary island of Gran Canaria, originally described as a separate species (Crocidura osorio), was later discovered to be a population of introduced greater white-toothed shrew.[5] Furthermore, a subspecies of the greater white-toothed shrew, Crocidura russula ibicensis, is found on the Mediterranean island of Ibiza.[6] In April 2008, the greater white-toothed shrew was discovered in Ireland as well. Its preferred habitats are grassland and woodland. It is slightly larger than the lesser white-toothed shrew but otherwise very similar and can often be distinguished only by close inspection of its teeth which are unpigmented.[7]
The greater white-toothed shrew is distinguished by a careful examination of its unpigmented teeth. Like other white-toothed shrews, C. russula lacks the deposition of iron in their enamel at the tips of their teeth.[8] This particular species has a greyish or reddish brown upper coat with a yellowish grey coat in the underside.[9] The greater white-toothed shrews are part of the medium-sized shrews and weigh around 11 to 14 grams.[3] The head and body length of C. russula is about 6 to 9 cm and the tail length averages to about 3 to 4.3 cm.[3]
C. russula are found in temperate regions with plentiful insects. They are generally found in habitats such as grasslands, woodlands, hedgegrows and prime agricultural areas. To prepare for colder seasons, these shrews can be found living near farms and gardens.[3] The greater white-toothed shrews tend to build their nest under stones, logs and in abandoned burrows. Typically these shrews are found in elevations below 1000 meters.[3]
The greater white toothed shrew is a carnivore, feeding mainly on invertebrates and occasionally small rodents, lizards and small amphibians.[3]
The greater white-toothed shrew is preyed upon by several animals; owls (such as Tyto alba), snakes, and small carnivorous mammals such as weasels and genets are the main predators of C. russula.[6] In order to avoid predation, the greater white-toothed shrews can be found under cover of vegetation or leaf litter when active. Cryptic coloration is also used as an effective method to avoid predation.[10]
The greater white-toothed shrews are classified as semi-social mammals. During winter, C. russula are found sharing nests and enter torpor.[11] Mated pairs are found guarding their territories together.[10] C. russula are highly monogamous and exhibit a female-biased dispersal, which is highly uncommon in mammals. This dispersal pattern can also occur due to infiltration and migration to empty breeding sites. Nonetheless, this dispersal pattern is a preventative measure for inbreeding.[3] The greater white-toothed shrew can be very vocal. C. russula possess a primitive form of echolocation where they produce a high pitched twittering call to interpret their environment. The use of this laryngeal call and vibrissae allow the shrews to find their way around their environment.[12] There have not been any concrete reports on the modes of communication used by this species, however, vocalization and tactile and chemical cues are likely to be used.[12]
The greater white-toothed shrew typically experiences one breeding season in its entire lifetime, whereby fertilization occurs right after parturition.[3] C. russula breed mainly from March to September, producing about four litters which can contain anywhere from 2 to 10 young. The sexual maturity in this species is fairly quick. The litters remain in their parental territory till the next breeding season.[3]
C. russula has a lifespan of about 18 months in the wild, but can survive for 30 months in captivity under laboratory conditions.[13]
C. russula serves as a prey species to many animals, however, an abundance in this species may lead to a decline in other small mammals such as pygmy shrews. In April 2008, the greater white-toothed shrew was discovered in Ireland and has since spread rapidly through the southern counties.[14][15] While the introduction of the species will possibly sustain threatened birds of prey, such as the barn owl, the nonnative mammal could threaten some of the smaller native species, such as the Eurasian pygmy shrew.[14]
The greater white-toothed shrew (Crocidura russula) is a small insectivorous mammal found in Europe and North Africa. It is the most common of the white-toothed shrews. This species is found along the Mediterranean, Netherlands, Belgium, Ireland, Germany and Portugal; in addition, the Osorio shrew of the Canary island of Gran Canaria, originally described as a separate species (Crocidura osorio), was later discovered to be a population of introduced greater white-toothed shrew. Furthermore, a subspecies of the greater white-toothed shrew, Crocidura russula ibicensis, is found on the Mediterranean island of Ibiza. In April 2008, the greater white-toothed shrew was discovered in Ireland as well. Its preferred habitats are grassland and woodland. It is slightly larger than the lesser white-toothed shrew but otherwise very similar and can often be distinguished only by close inspection of its teeth which are unpigmented.
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