| Cinereus shrew [1] | |
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Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Eulipotyphla |
| Family: | Soricidae |
| Genus: | Sorex |
| Species: | S. cinereus |
| Binomial name | |
| Sorex cinereus Kerr, 1792 | |
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| Cinereus shrew range | |
The cinereus shrew or masked shrew (Sorex cinereus) is a small shrew found in Alaska, Canada, and the northern United States. [2] This is the most widely distributed shrew in North America, where it is also known as the common shrew.
It is grey-brown in colour with a light grey underside and a pointed snout. It has a long tail that is brown on top and pale underneath with a dark tip. Its body is about 9 cm (3.5 in) in length including a 4 cm (1.6 in) long tail. It weighs about 5 g (0.18 oz). It has darker colouring than other shrews. Masked shrews can live up to two years, but, on average, only survive eighteen months.
In a long-term study done in Alaska, Yom-Tov and colleagues (2005) found that the masked shrew's body size contradicts Bergmann's Rule. [3] The study, done on 650 specimens and spanning from 1950 to 2003, examined body size in relation to ambient temperature. Measurements of body weight and the length of the tail, ear, hind foot, and body were taken. Results yielded that the masked shrew's body size decreased with high latitudes and with lower mean January temperatures, a trend that opposed Bergmann's Rule. It was suggested that this may be a coping mechanism to limit total energy requirements due to decreased food availability in winter months. Additionally, it was shown that body and tail length increased with rising temperatures during the second half of the twentieth century. This may be due to higher temperatures increasing the availability of the shrew's main diet.
The masked shrew is the most widely distributed shrew. [4] Its range covers most of northern North America extending south as far down to Maryland, along the Rocky Mountains in the west, and to the Appalachians in the east. This species was introduced into Newfoundland in the late 1950s. It can be found in many types of habitat like arid grasslands, moist areas, woodland, and tundra. The masked shrew mostly lives in humid areas and with high levels of vegetation to hide in. Moisture determines the abundance of this shrew.
Predators include larger shrews, hawks, owls, shrikes, snakes, herons, foxes, leopard frogs, bluebirds, brown trouts, and weasels. Masked shrews are susceptible to many types of parasites, like fleas and tapeworms. [5] Cowan and colleagues (2007) found that the high volume of food masked shrews consume causes them to be more susceptible to parasitism. Since males have larger ranges, they have a higher exposure to parasites. [5]
Masked shrews are opportunistic generalists. They eat insects, worms, snails, small rodents, salamanders, and seeds. Due to its high metabolism, the masked shrew can eat three times its weight a day. [6] The shrew has to eat almost constantly, because they can only survive a few hours without food. [6] Their metabolism drops when they are at rest.
McCay and colleagues (1997) found a higher abundance of masked shrews in non-irrigated forests due to a higher availability of larval insects, which is the preferred food source of the masked shrew. Masked shrews chose Lepidoptera larva over other food sources. [7]
This animal is active day and night year-round. Masked shrews can be nocturnal or diurnal depending on the weather. Doucet and colleagues (1974) showed that rain increases the nocturnal activity of the masked shrew, while cloud cover increases day and night activity. [8] It digs tunnels but also uses tunnels created by other small mammals. It uses dry grass to make nests in these tunnels. It can make high frequency pulses and has lateral scent glands. The home range of the masked shrew depends on availability of food, but it is on average 0.55 hectare. It has a low tolerance for other shrews in its home range. Merritt and colleagues (1995) found that its mass declined by half from summer to winter and non-shivering heat production, energy conservation, and reduced body mass. [4]
Masked shrews living at high latitudes are born in late spring and summer, reach adult size by the time they leave their nests, and complete their life cycle within a year. [3] They are born during spring or summer, remain immature in winter, and breed the following spring. [4] Masked shrews breed from May to September. Females have one litter of 6 to 7 young during the breeding season. The young are born hairless and clawless and have translucent abdominal walls. [6] Body mass increases and peaks at twenty days, then decreases when the young leave the nest after about 27 days. Masked shrews have a high chance of mortality during their first two months of life and most die during the first year. Masked shrews become sexually mature at two months, but wait until their first spring to breed.
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.
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 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 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 vagrant shrew, 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.
The prairie shrew is a small shrew found in the Canadian prairies and midwestern United States. At one time, this species was considered to be a subspecies of the similar cinereus shrew, S. cinereus.
The barren ground shrew is a small shrew found in northern Canada west of Hudson Bay and in Alaska. At one time, this species was considered to be a subspecies of the similar cinereus shrew. It is similar in appearance and thought to be closely related to the Saint Lawrence Island shrew and Pribilof Island shrew.
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.
The Asian house shrew is a shrew species native to South and Southeast Asia that has been listed as Least Concern on the IUCN Red List since 2008 because of its large population and wide distribution. It has been introduced in several West Asian and East African countries. It is considered an invasive species and implicated in the demise of several island lizard species.
The Eurasian least shrew, also called the lesser pygmy shrew, is the second-smallest mammal by mass after the Etruscan shrew.
Laxmann's shrew, or the masked shrew, is a species of shrew. Its range extends from northern Scandinavia and the Baltic to the Sea of Japan, including Hokkaidō, Sakhalin, and the Korean Peninsula. It favours mountain forests but is sometimes found in tundra and moorland, and also in lowland areas as well. It avoids cultivated land.
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.
Preble's shrew is a small shrew distributed across the Great Basin of the United States and southern British Columbia in Canada.
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.
| Authority control: National |
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