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.
- Biogeographic Regions
- palearctic
- Other Geographic Terms
- island endemic
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.
- Habitat Regions
- temperate
- terrestrial
- Terrestrial Biomes
- savanna or grassland
- forest
- Other Habitat Features
- agricultural
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.
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.
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.
- Other Physical Features
- endothermic
- homoiothermic
- bilateral symmetry
Reproduction
No information is available on mating systems for this species or other members of
the genus.
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.
- Key Reproductive Features
- iteroparous
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- fertilization
- viviparous
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
-
protecting
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-weaning/fledging
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-independence
-
protecting
- female
-
protecting
Lifespan/Longevity
The maximum lifespan in the wild is about three years. The maximum lifespan in captivity
is four years.
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.
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.
Females of the genus are typically territorial during breeding season, and will share
their nests with only one male.
Crocidura russula
has been known to ente torpor each day when held in captivity. It is not known whether
C. leucodon
does this also.
- Key Behaviors
- terricolous
- fossorial
- motile
- sedentary
- solitary
- territorial
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.
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.
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.
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.
- Primary Diet
-
carnivore
- eats terrestrial vertebrates
- insectivore
- 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.
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.
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.
Other Comments
The genus
Crocidura
has the most species of any mammalian genus with 158.
Additional Links
Contributors
Nancy Shefferly (editor), Animal Diversity Web.
Joshua Raese (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor, instructor), University of Wisconsin-Stevens Point.
- Palearctic
-
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- island endemic
-
animals that live only on an island or set of islands.
- 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.
- 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.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- agricultural
-
living in landscapes dominated by human agriculture.
- 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.
- 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.
- 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).
- seasonal breeding
-
breeding is confined to a particular season
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- fertilization
-
union of egg and spermatozoan
- viviparous
-
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
- 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.
- fossorial
-
Referring to a burrowing life-style or behavior, specialized for digging or burrowing.
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- solitary
-
lives alone
- 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
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- carnivore
-
an animal that mainly eats meat
- insectivore
-
An animal that eats mainly insects or spiders.
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.