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Crocidura russulawhite-toothed shrew

By Amanda Knoll

Geographic Range

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)

Habitat

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)

  • Range elevation
    1600 (high) m
    5249.34 (high) ft
  • Average elevation
    1000 m
    3280.84 ft

Physical Description

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)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    11 to 14 g
    0.39 to 0.49 oz
  • Range length
    6 to 9 cm
    2.36 to 3.54 in

Reproduction

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)

  • 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

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)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • male
      • female

Lifespan/Longevity

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)

  • Typical lifespan
    Status: wild
    18 (high) months
  • Average lifespan
    Status: wild
    1 months
  • Typical lifespan
    Status: captivity
    30 (high) months

Behavior

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)

Home Range

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

Communication and Perception

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)

Food Habits

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)

  • Animal Foods
  • mammals
  • reptiles
  • insects

Predation

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)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

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)

Economic Importance for Humans: Positive

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

  • Positive Impacts
  • research and education

Economic Importance for Humans: Negative

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

Conservation Status

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)

Other Comments

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

Contributors

Amanda Knoll (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor, instructor), University of Wisconsin-Stevens Point, Tanya Dewey (editor), Animal Diversity Web.

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

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

diurnal
  1. active during the day, 2. lasting for one day.
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.

forest

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

insectivore

An animal that eats mainly insects or spiders.

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).

monogamous

Having one mate at a time.

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.

nocturnal

active during the night

scrub forest

scrub forests develop in areas that experience dry seasons.

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

social

associates with others of its species; forms social groups.

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.

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.

ultrasound

uses sound above the range of human hearing for either navigation or communication or both

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

2003. "Arkive" (On-line). Accessed August 07, 2009 at http://www.arkive.org/greater-white-toothed-shrew/crocidura-russula/info.html.

2009. "The ICUN Red List of Threatened Species" (On-line). Accessed August 09, 2009 at http://www.iucnredlist.org/details/29652/0/full.

2009. "Wikipedia" (On-line). Greater White-Toothed Shrew. Accessed August 08, 2009 at http://en.wikipedia.org/wiki/Greater_White-toothed_Shrew.

Balloux, F., J. Goudet, N. Perrin. 1998. Breeding system and genetic variance in the monogamous, semi-social shrew, Crocidura russula . Evolution, 52(4): 1230-1235.

Bouteiller-Reuter, C., N. Perrin. 2005. Sex-specific selective pressures on body mass in the greater white-toothed shrew, Crocidura russula . Journal of Evolutionary Biology, 18(2): 290-300.

Duarte, L., C. Bouteiller, P. Fontanillas, E. Petit, N. Perrin. 2003. Inbreeding in the greater white-toothed shrew, Crocidura russula . Evolution, 57(3): 638-645.

Magnanou, E., J. Attia, R. Fons, G. Boeuf, J. Falcon. 2009. The timing of the shrew: Continuous melatonin treatment maintains youthful rhythmic activity in aging Crocidura russula . PLoS ONE, 4(6): e5904. Accessed August 08, 2009 at http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2690841.

Siemers, B., G. Schauermann, H. Turni, S. von Merten. 2009. "Biology Letters" (On-line). Why do shrews twitter? Communication or simple echo-based orientation. Accessed August 07, 2009 at http://rsbl.royalsocietypublishing.org/content/early/2009/06/12/rsbl.2009.0378.abstract..

Wiley-Blackwell, 2008. "ScienceDaily" (On-line). For Good Or Ill, Ireland Gains Another Mammal Species. Accessed August 09, 2009 at http://www.sciencedaily.com/releases/2008/04/080428071113.htm.

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