Northern short-tailed shrew
| Northern short-tailed shrew | |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Eulipotyphla |
| Family: | Soricidae |
| Genus: | Blarina |
| Species: | B. brevicauda |
| Binomial name | |
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Blarina brevicauda (Say, 1823) |
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The northern short-tailed shrew (Blarina brevicauda) is the largest shrew in the genus Blarina, and occurs in the northeastern region of North America. It is a semifossorial, highly active, and voracious insectivore and is present in a variety of habitats. It is notable in that it is one of the few venomous mammals. The specific epithet, brevicauda, is a combination of the Latin brevis and cauda, meaning "short tail".
B. brevicauda is a red-toothed shrew, one of three or four species (depending on the authority) in the genus Blarina. It was formerly considered to be a sister subspecies of the southern short-tailed shrew (B. carolinensis). The species has been divided into 11 subspecies based on morphological characteristics, which are grouped into two semispecies: B. b. brevicauda and B. b. talpoides; these groupings were mirrored by a molecular systematics study of the sequence. The two groups of subspecies are thought to have been kept isolated from each other by glaciers.
This shrew has a total length of 108 to 140 mm (4.3 to 5.5 in), of which 18 to 32 mm (0.71 to 1.26 in) is tail; and weighs 15 to 30 g (0.53 to 1.06 oz). The species exhibits slight sexual dimorphism in size, with the male being slightly larger than the female. The dorsal fur is thick and velvety, and can be black, brownish black, or silvery gray, with the ventral fur being a bit lighter and grayer. The shrew molts from a summer coat which is shorter and paler than the winter pelage in October and November, and back again sometime in February through July. The tail is quite short, amounting to less than 25% of the total length. The dental formula is I 3-3/1-1, C 1-1/1-1, P 3-3/1-1, M 3-3/3-3 = 16/16 = 32. Three well-developed scent glands are present, one on each side of the animal and one placed ventrally; the scent may be used for marking territories, though the shrew's sense of smell is thought to be poor.
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Wikipedia