| Vagrant shrew [1] | |
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Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Eulipotyphla |
| Family: | Soricidae |
| Genus: | Sorex |
| Species: | S. vagrans |
| Binomial name | |
| Sorex vagrans Baird, 1857 | |
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| Vagrant shrew range | |
The vagrant shrew (Sorex vagrans), also known as the wandering shrew, is a medium-sized North American shrew. At one time, the montane shrew and the Orizaba long-tailed shrew were considered to belong to the same species.
This animal inhabits open and wooded areas in western Canada and the United States west of the Continental Divide. [3] In Canada, it is found in southern British Columbia, including Vancouver Island, and as far east as extreme south-western Alberta. In the United States, it is found throughout most of Washington, Oregon, and Idaho, as far south as central California, in northern and central Nevada, northern Utah, and western Montana and Wyoming. [4]
Their preferred habitat appears to be wet grassland and meadows, ranging from alpine tundra to swampland, and they are often found close to rivers or other sources of water. They are also found in open coniferous forest, but only rarely in dense woodlands. Because they often use fallen logs as cover, they prefer areas with moderate amounts of woody debris, [4] and they may also prefer areas with more acidic soils than other local shrew species. [5] One subspecies is found only in salt marshes. [6]
There are three recognised subspecies: [4]
Pleistocene fossils attributed to the species have been reported from Arkansas, New Mexico, and Texas. However, such fossils can be difficult to distinguish at the species level, and may represent close relatives such as montane or Pacific shrews. [7]
Vagrant shrews are generally red brown in color with white or grey underparts, although coastal populations can be much darker, being almost black on the upper parts of the body. They have a long tail which is sometimes paler in color underneath, especially in juveniles. Although similar in appearance to other shrews found in the same area, it can be distinguished from the montane shrew by its smaller size and shorter tail, and by having a smaller number of friction pads on the hind feet. It can most readily be distinguished from Trowbridge's shrew by examining fine details of the shape of the skull, although the latter species also tends to have a more distinctly pale underside to the tail in adults. [4]
During winter, its fur is dark brown. [3] The fall molt occurs between September and October, beginning firstly on the rump and progressing forwards, and then, separately, on the snout, and moving backwards. The timing of the spring molt is much more variable, even in the same population, so that individuals with summer and winter coats can be found together for several months during the spring, and even into the early summer. [4]
Its body is about 10 centimetres (3.9 in) in total length, including a 4 centimetres (1.6 in) long tail. The adult body weight ranges from 4 to 8 grams (0.14 to 0.28 oz), with males being slightly larger than females. [3] [4] The basal metabolic rate of vagrant shrews is 5.4 ml O2/g/h, [8] with no evidence of torpor in winter. [4]
They are referred to sometimes as wandering shrews. [9]
Vagrant shrews feed mainly on earthworms, spiders, insects, and other small invertebrates, but also eat some plant material. Because of their high metabolic rate, they have been reported to consume over 160% of their own body weight in food each day. Their primary predators include owls, and even bobcats. [4]
They are active throughout the day, typically for just five to ten minutes at a time before resting. They do, however, spend longer periods of time foraging at night than they do during the hours of daylight. They are generally solitary outside the spring breeding season, defending home ranges of around 1,000 m2 (11,000 sq ft), by squeaking and making short charges at intruders, although actual fighting is rare. During the spring, home ranges are much larger, especially for the males. [5]
Throughout most of the year, vagrant shrews construct shallow cup-shaped nests, up to 8 cm (3.1 in) across, from vegetation and animal hair. In winter, they cover the nests with a domed roof to provide shelter. Females also construct similar domed nests during the breeding season, in which to rear their young. These are, however, larger than the winter nests, and may reach as much as 24 cm (9.4 in) across and up to 6 cm (2.4 in) in height. [4] Vagrant shrews sometimes use echolocation to orient themselves in unfamiliar locations, although they are probably not able to use it to locate prey. [10]
It often uses runways created by voles.[ citation needed ]
Vagrant shrews primarily breed between April and June, although births may occur as early as February, or as late as September. Gestation lasts twenty days, and results in the birth of a litter of two to eight young. [6] A female may give birth to up to three litters each year. [4] The young are born hairless and blind, weighing less than 0.5 g (0.018 oz) each. They grow rapidly throughout the first few weeks of life, beginning to develop fur by two weeks, opening their eyes by three weeks, and being weaned between sixteen and twenty five days after birth. [6]
The average life expectancy of a vagrant shrew has been estimated at a little over six months. However, they can live much longer; although few survive for more than seventeen months, a few survive their second winter and reach two years of age. [4]
Shrews are small mole-like mammals classified in the order Eulipotyphla. True shrews are not to be confused with treeshrews, otter shrews, elephant shrews, West Indies shrews, or marsupial shrews, which belong to different families or orders.
The red-toothed shrews of the subfamily Soricinae are one of three living subfamilies of shrews, along with Crocidurinae and Myosoricinae. In addition, the family contains the extinct subfamilies Limnoecinae, Crocidosoricinae, Allosoricinae and Heterosoricinae. These species are typically found in North America, northern South America, Europe and northern Asia. The enamel of the tips of their teeth is reddish due to iron pigment. The iron deposits serve to harden the enamel and are concentrated in those parts of the teeth most subject to wear. Members of the genera Chimarrogale, Nectogale, Neomys (Nectogalini) and some members of Sorex (Soricini) are known as water shrews, due to having a semi-aquatic lifestyle.
The northern short-tailed shrew 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 like broadleaved and pine forests among shrubs and hedges as well as grassy river banks. 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".
The cinereus shrew or masked shrew is a small shrew found in Alaska, Canada, and the northern United States. This is the most widely distributed shrew in North America, where it is also known as the common shrew.
The American pygmy shrew is a small shrew found in Northern Alaska, Canada, and the northern United States, south through the Appalachian Mountains. It was first discovered in 1831 by naturalist William Cane in Georgian Bay, Parry Sound.
The Arctic shrew, also known as the blackback shrew or saddlebacked shrew, is a medium-sized shrew found in Canada and the northern United States. Separate species status has been proposed for the maritime shrew which is found in New Brunswick and Nova Scotia and had been considered to be a subspecies of the Arctic shrew. The tundra shrew was formerly considered to be a subspecies of the Arctic shrew.
The marsh shrew, also known as the Pacific water shrew, Bendire's water shrew, Bendire's shrew and Jesus shrew is the largest North American member of the genus Sorex. Primarily covered in dark-brown fur, it is found near aquatic habitats along the Pacific coast from southern British Columbia to northern California. With air trapped in its fur for buoyancy, marsh shrews can run for three to five seconds on top of the water. It measures about 16 cm (6.3 in) in length, including a 7-centimetre (2.8 in)-long tail, and weighs an average of 14.5–16 g (0.51–0.56 oz). The marsh shrew's diet consists mainly of invertebrates, which it hunts on land and in the water. They are rare; their populations are thought to be in decline, and they are considered endangered in parts of their range.
The smoky shrew is a medium-sized North American shrew found in eastern Canada and the northeastern United States and extends further south along the Appalachian Mountains.
The southern short-tailed shrew is a gray, short-tailed shrew that inhabits the eastern United States.
The genus Sorex includes many of the common shrews of Eurasia and North America, and contains at least 142 known species and subspecies. Members of this genus, known as long-tailed shrews, are the only members of the tribe Soricini of the subfamily Soricinae. They have 32 teeth.
The Eurasian pygmy shrew, often known simply as the pygmy shrew, is a widespread shrew of the northern Palearctic.
The common shrew, also known as the Eurasian shrew, is the most common shrew, and one of the most common mammals, throughout Northern Europe, including Great Britain, but excluding Ireland. It is 55 to 82 millimetres long and weighs 5 to 12 grams, and has velvety dark brown fur with a pale underside. It is one of the rare venomous mammals. Juvenile shrews have lighter fur until their first moult. The common shrew has small eyes, a pointed, mobile snout and red-tipped teeth. It has a life span of approximately 14 months.
Elliot's short-tailed shrew is a small, slate grey, short-tailed species of shrew. Its common name comes from Daniel Giraud Elliot, who first described the species in 1899.
Sorex ornatus sinuosus, the Suisun shrew or Suisun ornate shrew, is a subspecies of the ornate shrew that occurs in the tidal marshes of the northern shores of San Pablo and Suisun bays. Brown and Rudd redefined the western boundary of the range from a prior designation of the Petaluma River. The Suisun shrew has been designated as a Species of Concern by the U.S. government and a Mammalian Species of Special Concern by the state of California.
The montane shrew is a species of mammal in the family Soricidae commonly known as the dusky shrew. Monticolus is derived from the Latin root word mons meaning mountain. It is found in Alaska, western Canada, the western United States in Washington, Idaho, Montana, Utah, Colorado, New Mexico, Arizona, Oregon, Nevada, and California, as well as in Mexico.
The dwarf shrew is a species of mammal in the family Soricidae endemic to Arizona, Colorado, Montana, Nebraska, New Mexico, South Dakota, Utah, and Wyoming in the United States. The type locality is Estes Park, Colorado, USA.
The ornate shrew is a species of mammal in the family Soricidae (shrews). It is endemic to western North America, ranging from Northern California in the United States to Baja California in Mexico. Eight subspecies are known, including the extinct tule shrew, known only from four specimens collected in 1905, and the Suisun ornate shrew, a species of conservation concern in California. Through skull morphology research and genetic testing on Ornate shrew populations, it has been shown that there are three main genetic subdivisions: The Southern, Central and Northern. These three genetic subdivisions of Ornate shrew arose from populations of Ornate shrews getting geographically isolated from other populations.
The Inyo shrew is a species of shrew found in the western United States. It is light gray and white in color, with a narrow skull and small body size, very similar in appearance to the related dwarf shrew, but paler and not as large. It can be found in many different habitats, from rocky, mountainous regions to wetlands and riparian areas. Not much is known about its behavioral and reproductive habits. While barely studied, their population is believed to be stable and not under any threat.
Trowbridge's shrew is a species of mammal in the family Soricidae. It is found in southern British Columbia in Canada and in Washington, Oregon, and California in the United States.
The long-tailed shrew or rock shrew is a small shrew found in Atlantic Canada and the Northeastern United States.
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