Jump to content

Shrew

From Wikipedia, the free encyclopedia

This is an old revision of this page, as edited by Zondi (talk | contribs) at 05:17, 21 August 2007 (Correcting spelling: thier->their). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Shrews[1]
Temporal range: Middle Eocene to Recent
Southern Short-tailed Shrew
Scientific classification
Kingdom:
Phylum:
Class:
Order:
Family:
Soricidae

Subfamilies

Crocidurinae
Myosoricinae
Soricinae

Shrews are small, superficially mouse-like mammals of the family Soricidae. Although their external appearance is generally that of a long-nosed mouse, the shrews are not rodents and not closely related: the shrew family is part of the order Soricomorpha. Shrews have feet with five clawed toes, unlike rodents, which have four. Shrews are also not to be confused with treeshrews, which belong to their own unrelated order, the Scandentia.

There are 376 species of shrew in 26 genera, which are grouped into three living subfamilies: Crocidurinae (white-toothed shrews), Myosoricinae (African white-toothed shrews) and Soricinae (red-toothed shrews). In addition, the family contains the extinct subfamilies Limnoecinae, Crocidosoricinae, Allosoricinae and Heterosoricinae (although Heterosoricinae is also commonly considered a separate family). Shrews are distributed almost worldwide: of the major temperate land masses, only New Guinea, Australia, and New Zealand do not have native shrews at all; South America has shrews only in the far-northern tropical part, like in Colombia. In terms of species diversity, the shrew family is the fourth most successful mammal family of all, being rivalled only by the muroid families Muridae and Cricetidae and the bat family Vespertilionidae.

In general, shrews are terrestrial creatures that forage for seeds, insects, nuts, worms and a variety of other foods in leaf litter and dense vegetation, but some specialise in climbing trees, living underground, in the subniveal layer or even hunting in water. All shrews are small, most no more than mouse size. The largest species is the House Shrew (Suncus murinus) of tropical Asia which is about 15 cm long and weighs around 100 grams; several are very small, notably the Etruscan Shrew (Suncus etruscus) which at about 3.5 cm and 2 grams is one of the smallest living mammals. Shrews have a gestation period of 17–32 days and live for between 12 and 30 months.[2] [citation needed]

Shrews are unusual among mammals in a number of respects. Unlike most mammals, some species of shrew are venomous. Also, along with the bats and toothed whales, some species of shrew use echolocation.

Shrews have a high metabolic rate and so must eat 80-90 per cent of their own body weight in food daily. Shrews are not able to hibernate.

Unlike most other mammals, shrews are born with permanent teeth and do not have a zygomatic bone.

Shrews hold nearly 10% of their mass in their brain, a relatively high brain to body mass ratio.[3]

Shrews, such as Rosemary, can also be very kind and sweet animals if given a chance to show their true colors.

Metaphorical usage

In the English language, the word shrew is also used to describe a woman with a violent, scolding, or nagging temperament, as in Shakespeare's play The Taming of the Shrew.

Classification

According to Hutterer (2005), there are 26 genera of shrews divided into three subfamilies.

References

  1. ^ Hutterer, R. (2005). Wilson, D.E.; Reeder, D.M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. pp. 223–300. ISBN 978-0-8018-8221-0. OCLC 62265494.
  2. ^ Macdonald (Ed), Professor David W. (2006). The Encyclopedia of Mammals. Oxford University Press. ISBN 0-19-920608-2. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help)
  3. ^ Brains of White Matter