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Crocidura leucodonbicolored shrew

By Joshua Raese

Geographic Range

Crocidura leucodon, one of the white-toothed shrews, is distributed from central Europe eastward to the Caspian Sea. The species is absent from southern France, the Iberian Peninsula, and the islands of the Mediterranean Sea except for Lesbos. (Corbet and Ovenden, 1980; Mitchell-Jones, et al., 1999)

Habitat

Bicolored white-toothed shrews are associated with dry, upland habitats such as grasslands, woodlands, and roadside brush. On the northern fringe of the species' range, individuals often lives in gardens, outhouses, and farm buildings. These animals tunnel through leaf litter as well as under brush and rock piles. These shrews are usually found below 1000 m in elevation except in the Alps, where they may be found as high as 1600 m. (Corbet and Ovenden, 1980; Grzimek, 1990; Nowak, 1999)

  • Range elevation
    0 to 1600 m
    0.00 to 5249.34 ft
  • Average elevation
    below 1000 m
    ft

Physical Description

Crocidura leucodon is dark gray-brown or chestnut-brown on its back, and white or gray on its underside. A sharply defined line separates the two colors on the sides, contributing to the common name "bicolored white toothed shrew.". The body is 68 to 87 mm in length, and the tail is 29 to 46 mm. Bicolored shrews have a mass ranging between 6 and 13 g. The tail is covered with long, protruding hairs at right angles. (Corbet and Ovenden, 1980; Grzimek, 1990; Nowak, 1999)

Bicolored shrews have interesting dentition. Their teeth are white, because they lack pigment. In addition, these shrews have three unicuspid teeth in the upper jaw. The dental formula is 3/1 1/0 1/2 3/3 = 28 teeth. (Corbet and Ovenden, 1980; Grzimek, 1990; Nowak, 1999)

The skull of C. leucodon is differentiated from that of greater white-toothed shrews by a rostrum that is shorter and deeper, and unicuspid teeth that are more crowded. (Corbet and Ovenden, 1980; Grzimek, 1990; Nowak, 1999)

  • Range mass
    6 to 13 g
    0.21 to 0.46 oz
  • Range length
    97 to 133 mm
    3.82 to 5.24 in
  • Average basal metabolic rate
    0.166 W
    AnAge

Reproduction

No information is available on mating systems for this species or other members of the genus. (Nowak, 1999)

The breeding season for C. leucodon runs from March to September with 2 to 4 litters being produced during that time. The gestation period is 28 to 31 days with 3 to 10 young born per litter. The young weigh between 0.8 and 0.9 g and are hairless for the first week after birth. They are fully haired by 16 days of age, and open their eyes at 13 days. The young are weaned at 18 to 22 days, and reach sexual maturity at 8 to 10 months of age. (Grzimek, 1990; Nowak, 1999)

  • Breeding interval
    These shrews are capable of producing a litter each month and a half during the breeding season.
  • Breeding season
    March to September
  • Range number of offspring
    3 to 10
  • Average number of offspring
    5
    AnAge
  • Range gestation period
    28 to 31 days
  • Range weaning age
    18 to 22 days
  • Range age at sexual or reproductive maturity (female)
    8 to 10 months
  • Range age at sexual or reproductive maturity (male)
    8 to 10 months

There is a paucity of information on the parental care of this species. The mother undoubtedly cares for the altricial young in a nest, providing them with milk, protection, and grooming. Male parental care has not been reported for this genus.

Crocidura leucodon, and other central-European members of the genus, exhibit one of the more interesting parent/offspring behaviors of shrews: caravanning. When a nest is disturbed, or when the young are ready to move around but are not yet independent, the mother will lead her litter around, with each shrew holding on to the hind end of the shrew in front of it, in a giant chain, or caravan.

  • Parental Investment
  • no parental involvement
  • altricial
  • pre-fertilization
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • protecting
      • female

Lifespan/Longevity

The maximum lifespan in the wild is about three years. The maximum lifespan in captivity is four years. (Grzimek, 1990; Nowak, 1999)

Behavior

The behavior of this species is apparently not well studied. However, there is information on other shrews in the genus Crocidura, and C. leucodon is probably similar.

Members of this genus are reported to be voracious and aggressive. They will eat just about anything they can sink their teeth into, and especially animals. When threatened, these shrews commonly crouch on the ground, raise their heads, bare their teeth, and squeak. (Nowak, 1999)

Although many species are thought to be solitary, some species of the genus Crocidura show social tolerance, and even will group together during winter, with as many as 8 individuals sharing a nest. This probably has thermoregulatory advantages to these small animals when the weather is cold. (Nowak, 1999)

Females of the genus are typically territorial during breeding season, and will share their nests with only one male. (Nowak, 1999)

Crocidura russula has been known to ente torpor each day when held in captivity. It is not known whether C. leucodon does this also. (Nowak, 1999)

Home Range

The home range size for C. leucodon has not been reported. However, another member of the genus, C. suaveolens is reported to have ahome range size of 56 to 395 sqare meters. (Nowak, 1999)

Communication and Perception

The only reported call is a single sharp, metallic squeak emitted when the shrew is disturbed. However, it is likely that there may be other vocalizations which serve as communication in this species. (Nowak, 1999)

All members of the genus Crocidura have well developed scent glands. Those of males are especially prominent. It is likely that these glands serve some communicative purpose related to reproduction. (Nowak, 1999)

As in other mammals, tactile communication is important in this species. Caravanning in the young is a means by which the mother commmunicates to the litter where they should move. There are undoubtedly other forms of tactile information that are passed between mothers and their offspring, between mates, and between rivals.

Shrews are not known for having excellent vision, so it is unlikely that visual communication is very important in this species.

Food Habits

Bicolored white-toothed shrews feed mainly on small mammals, frogs, toads, lizards, and invertebrates. Captive specimens have displayed the behavior of eating everything but the skin, tail, and parts of limbs of their prey. The brain is always consumed first. (Nowak, 1999)

  • Animal Foods
  • mammals
  • amphibians
  • reptiles
  • insects

Predation

The main predators of C. leucodon are thought to be owls, snakes, and carnivorous mammals. However, details on which species actually take these shrews are not available. (Grzimek, 1990)

Ecosystem Roles

These shrews are utilized by a variety of animals for food, so probably have some affect on their populations. Also, these shrews are known to eat insects and invertebrates, having some negative impact on their populations. (Grzimek, 1990)

Economic Importance for Humans: Positive

It is unlikely that these small insectivores have any positive economic impact on humans.

Economic Importance for Humans: Negative

No information on any negative economic impact of this species on humans.

Conservation Status

Crocidura leucodon has no special conservation status. Although this is a common species, its populations may be slightly decreasing in the northern and western portions of its range due to intensive agriculture in those regions. (Mitchell-Jones, et al., 1999)

Other Comments

The genus Crocidura has the most species of any mammalian genus with 158. (Nowak, 1999)

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Joshua Raese (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor, instructor), University of Wisconsin-Stevens Point.

Glossary

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

fossorial

Referring to a burrowing life-style or behavior, specialized for digging or burrowing.

insectivore

An animal that eats mainly insects or spiders.

island endemic

animals that live only on an island or set of islands.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

Corbet, G., D. Ovenden. 1980. The Mammals of Britain and Europe. Glascow: Wm Collins Sons.

Grzimek, B. 1990. Pp. 488-489 in Grzimek's Encyclopedia of Mammals, Vol. 1. New York, New York, U.S.A: McGraw-Hill.

Mitchell-Jones, A., G. Amori, W. Bogdanowicz, B. Krystufek, P. Reijnders. 1999. Pp. 64-65 in The Atlas of European Mammals. London, U.K: Academic Press.

Nowak, R. 1999. Pp. 221 in Walker's Mammals of the World, Vol. 1. Baltimore and London: The Johns Hopkins University Press.

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