The greater white-toothed shrew (''Crocidura russula'') is a small

insectivorous A robber fly eating a hoverfly An insectivore is a carnivorous animal or plant that eats insects. An alternative term is entomophage, which can also refer to the human practice of eating insects. The first vertebrate insectivores were ...

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

found in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

and

North Africa North Africa, or Northern Africa is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region, and it is sometimes defined as stretching from the Atlantic shores of Mauritania in ...

. It is the most common of the white-toothed shrews. This species is found along the

Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the e ...

, Netherlands, Belgium, Ireland, Germany and Portugal; in addition, the Osorio shrew of the

Canary Canary originally referred to the island of Gran Canaria on the west coast of Africa, and the group of surrounding islands (the Canary Islands). It may also refer to: Animals Birds * Canaries, birds in the genera ''Serinus'' and ''Crithagra'' i ...

island of

Gran Canaria Gran Canaria (, ; ), also Grand Canary Island, is the third-largest and second-most-populous island of the Canary Islands, an archipelago off the Atlantic coast of Northwest Africa which is part of Spain. the island had a population of that co ...

, 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 Ibiza (natively and officially in ca, Eivissa, ) is a Spanish island in the Mediterranean Sea off the eastern coast of the Iberian Peninsula. It is from the city of Valencia. It is the third largest of the Balearic Islands, in Spain. Its l ...

. In April 2008, the greater white-toothed shrew was discovered in Ireland as well. Its preferred habitats are

grassland A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...

and

woodland A woodland () is, in the broad sense, land covered with trees, or in a narrow sense, synonymous with wood (or in the U.S., the ''plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunlight and limited shade (see ...

. It is slightly larger than the

lesser white-toothed shrew The lesser white-toothed shrew (''Crocidura suaveolens'') is a tiny shrew with a widespread distribution in Africa, Asia and Europe. Its preferred habitat is scrub and gardens and it feeds on insects, arachnids, worms, gastropods, newts and sm ...

but otherwise very similar and can often be distinguished only by close inspection of its

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

which are unpigmented.

Physical description

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. This particular species has a greyish or reddish brown upper coat with a yellowish grey coat in the underside. The greater white-toothed shrews are part of the medium-sized shrews and weigh around 11 to 14 grams. 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.

Habitat

''C. russula'' are found in temperate regions with plentiful insects. They are generally found in habitats such as

grasslands A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natural ...

, woodlands, hedgegrows and prime

agricultural Agriculture or farming is the practice of cultivating Plant, plants and livestock. Agriculture was the key development in the rise of Sedentism, sedentary human civilization, whereby farming of Domestication, domesticated species created food ...

areas. To prepare for colder seasons, these shrews can be found living near farms and gardens. 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.

Diet

The greater white toothed shrew is a

carnivore A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...

, feeding mainly on

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s and occasionally small

rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...

lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...

s and small

amphibian Amphibians are tetrapod, four-limbed and ectothermic vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terres ...

Predation

The greater white-toothed shrew is preyed upon by several animals;

owl Owls are birds from the order Strigiformes (), which includes over 200 species of mostly solitary and nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp talons, and feathers a ...

s (such as ''Tyto alba''),

snake Snakes are elongated, Limbless vertebrate, limbless, carnivore, carnivorous reptiles of the suborder Serpentes . Like all other Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales. Ma ...

s, and small

carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...

mammals such as

weasel Weasels are mammals of the genus ''Mustela'' of the family Mustelidae. The genus ''Mustela'' includes the least weasels, polecats, stoats, ferrets and European mink. Members of this genus are small, active predators, with long and slender bo ...

s and genets are the main

predators Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...

of ''C. russula''. In order to avoid predation, the greater white-toothed shrews can be found under cover of vegetation or leaf litter when active.

Cryptic coloration Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...

is also used as an effective method to avoid predation.

Behavior

The greater white-toothed shrews are classified as semi-social mammals. During winter, ''C. russula'' are found sharing nests and enter torpor. Mated pairs are found guarding their territories together. ''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. 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 Vibrissae (; singular: vibrissa; ), more generally called Whiskers, are a type of stiff, functional hair used by mammals to sense their environment. These hairs are finely specialised for this purpose, whereas other types of hair are coarser ...

allow the shrews to find their way around their environment. 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.

Reproduction

The greater white-toothed shrew typically experiences one breeding season in its entire lifetime, whereby

fertilization Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Proce ...

occurs right after

parturition Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause the muscular walls of the uterus to contract, expelling the f ...

. ''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.

Life span

''C. russula'' has a lifespan of about 18 months in the wild, but can survive for 30 months in captivity under laboratory conditions.

Role in the ecosystem

''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 Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...

and has since spread rapidly through the southern counties. While the introduction of the species will possibly sustain threatened birds of prey, such as the

barn owl The barn owl (''Tyto alba'') is the most widely distributed species of owl in the world and one of the most widespread of all species of birds, being found almost everywhere except for the polar and desert regions, Asia north of the Himalaya ...

, the nonnative mammal could threaten some of the smaller native species, such as the

Eurasian pygmy shrew The Eurasian pygmy shrew (''Sorex minutus''), often known simply as the pygmy shrew, is a widespread shrew of the northern Palearctic. Description It measures about in length, not including the tail, and has an average weight of .The hair on t ...

References

{{Taxonbar, from=Q572732 Crocidura Mammals of Europe Mammals of North Africa Mammals described in 1780