Soricidae: Shrew Family
Shrews are active creatures with high metabolisms. Their hearts may beat more than 1,200 times every minute and, relative to their body size, they have enormous appetites. Even in cold northern regions, they do not hibernate in winter; it would be impossible for them to build up sufficient fat reserves.
Some species of shrew are reported to eat their own feces and perhaps those of other creatures. By doing so, they boost their intake of vitamins В and К and some other nutrients.
This habit may be related to the shrews’ hyperactive life and enhanced metabolism. Shrews rely heavily on their senses of smell and hearing when hunting — their eyes are tiny and probably of little use.
This solitary species, also called the dusky shrew, occurs from northern Alaska southward to New Mexico, and from the west coast to Manitoba in the east. It occurs in a variety of habitats, including tundra in the far north, prairies in drier parts of the range and also mountain forests. All these habitats have some ground vegetation in which the shrews can hide from predators. Montane shrews feed on insect larvae, spiders, earthworms and occasionally small salamanders. They also eat non-animal foods such as seeds and mushrooms.
Size: 6 - 8 cm (2.5 - 3 in); 5.9 - 7.2 g (0.2 - 0.25 oz).
This is one of the most unusual members of the shrew family. The armored shrew has a spine which is fortified and strengthened. Despite this unique skeletal structure, the armored shrew moves much like other shrews, although its predatory behavior is characterized by rather ponderous and apparently well thought-out movements.
There are reports that an armored shrew is able to support the weight of a grown man without being crushed.
Armored shrews appear to eat plant food as well as invertebrates. They are believed to breed throughout the year.
Range: Africa: Uganda, near Kampala.
Size: Body: 4 3/4 - 6 in (12 - 15 cm); Tail: 2 3/4 - 3 3/4 in (7 - 9.5 cm).
Giant Mole Shrew
Giant mole shrews live in most land habitats within their range, but they are hard to spot. They use their strong forepaws and flexible snouts to dig deep burrows in soft earth and, when on the surface, they scurry out of sight beneath mats of leaves or snow. However, they do climb into trees in search of food on occasion.
Giant mole shrews have stout bodies with long, pointed snouts covered in sensitive whiskers. Their eyes are very small because they spend most of the time underground, and their ears are hidden under thick coats of grey hairs.
These small mammals feed at all times of the day and night. They rest in nests of grass and leaves made inside their tunnels or in nooks and crannies on the surface. Giant mole shrews will eat plant food, but they also hunt for small prey, such as snails, mice and insects. Their saliva contains a venom that paralyzes prey animals. In the mating season, which takes place between spring and autumn, they expand their territories so that they overlap with those of the opposite sex.
Distribution: Central Canada to south-eastern United States.
Habitat: All land habitats.
Food: Insects, small vertebrates, seeds and shoots.
Size: 12 - 14 cm (5 - 5.5 in); 15 - 30 g (0.5 - 1 oz).
Maturity: 6 weeks.
Breeding: Litters of 5 - 7 young born throughout the summer.
Life span: 2 years.
Southern Short-tailed Shrew
This species ranges from southern Illinois to Florida. It prefers to live in damp habitats with well-drained soil for burrowing. It is especially common in woodlands, where the roots of trees create good conditions for digging tunnels.
The southern short-tailed shrew is the smallest in its genus, with members of the species having as few as 36 chromosomes, while their larger relatives, the giant mole shrews, have between 48 and 50.
This is the smallest of the short-tailed shrews. Its fur is almost a completely uniform grey, which becomes slightly paler in summer. As with most shrews, this species has a long flexible nose for probing through loose soil.
Southern short-tailed shrews are nocturnal. Even when active, they are often hidden away in tunnels and runways among leaf litter and grass. They are most likely to be seen just after rainfall. The rain water trickles though the soil, flooding lower levels, and this forces insects and worms that are living underground up to the surface, where the shrews are ready and waiting. The shrews also supplement their diet with berries.
Young shrews are born blind and helpless, and are cared for in a nest of grass and other dry vegetation under a log, stump or underground.
Distribution: South-eastern North America.
Habitat: Moist woodlands.
Food: Insects and worms.
Size: 7.5 - 10.5 cm (2.9 - 4.1 in); 15 - 30 g (0.5 - 1 oz).
Maturity: 12 weeks.
Breeding: Several litters produced in summer.
Life span: 1 year.
Elliot's Short-tailed Shrew
Elliot's short-tailed shrew lives in the Midwest region of the United States. It inhabits forests and grasslands, and has adapted to life in the huge wheat and corn fields that cover its range. It requires soft soil for burrowing through and is common close to the banks of rivers, where the damp earth is looser than in drier areas. However, the shrew never takes to the water. It is a skilled climber and forages for insects and plant food all year round. It does not hibernate and generally survives for no more than a year. It relies on stores of food laid down in autumn to get it through the winter.
Size: 9.2 - 12 cm (3.6 - 4.75 in); 15 g (0.5 oz).
This shrew is found on the Gaspe Peninsula of eastern Quebec, and in two small ranges in New Brunswick and on Cape Breton Island. Gaspe shrews live in mountain conifer forests, where they forage among the leaf litter or mosses that grow on the forest floor. They are grey all over, with a very narrow snout. Their diet comprises mainly grubs, maggots and spiders, but they also eat worms, snails, slugs and plant matter.
Size: 9.5 - 12.5 cm (3.75 - 5 in); 2.2 - 4.3g (0.1 oz).
Giant Mexican Shrew
Although members of this species are consistently large, they are not by any means the largest of the shrews. They get their "giant" moniker from the fact that they are the last surviving member of the Megasorex genus, which once contained truly giant shrews. Giant Mexican shrews live in tropical forests and grasslands in western Mexico. They find worms, grubs and other invertebrate prey by rooting through loose soil and leaf litter with their pointed snout.
Size: 8 - 9 cm (3.25 - 3.5 in); 10 - 12 g (0.3 - 0.4 oz).
This is North America's most widespread shrew, ranging across Canada and Alaska and much of the northern United States. Masked shrews occupy a range of habitats, wherever there is adequate ground cover. They are most commonly found in wet areas, such as near to streams or in marshes. Among American mammals, only the pygmy shrew is smaller than this species.
Size: 7 cm (2.75 in); 2.5 - 4 g (0.1 oz).
Inhabiting alpine grasslands up to an altitude of 3,400m (11,333 ft) above sea level, alpine shrews are often found in rocky habitats. They are especially common on stony banks and beds of fast-flowing mountain streams, seeking out invertebrate prey. Unlike most shrew species, alpine shrews are adept climbers.
Size: 6 - 7.5 cm (2.5 - 3 in); 5.5 - 11.5 g (0.01 - 0.025 lb).
Pygmy White-toothed Shrew
One of the world's smallest mammals, pygmy white-toothed shrews are found across southern Europe. These shrews have scent glands on their sides, which secrete a pungent odour. The glands are especially well developed in the males during the breeding season, when they are trying to intimidate their rivals and impress females.
Size: 3.5 - 5.2 cm (1.5 - 2in); 1.5 - 2.5 g (0.003 - 0.005 lb).
Asian Musk Shrew
This species lives in large numbers in and around human settlements, and is very common in houses throughout its range. It originated in India, but has been spread by people, right the way down the coast of East Africa and all the way east across Asia to Indonesia and a number of oceanic islands, including Mauritius and Guam, where it threatens small native reptiles.
Size: 7.5 - 12 cm (3 - 4.8 in); 10 - 32 g (0.02 - 0.07 lb).
This strange shrew lives in large parts of China and South-east Asia and, although it is in the shrew family, it looks and behaves much more like a mole. It lives in mountain forests up to 3,100 m (10,000 ft) above sea level, and spends its time underground, burrowing among the roots of plants, searching for insects and earthworms that form its diet.
Size: 8.5 - 11 cm (3.4 - 4.5 in); 14 - 25 g (0.03 - 0.05 lb).
The long-tailed shrew is found as far north as Nova Scotia in eastern Canada. From there it ranges south to Tennessee and North Carolina in the southern United States. This shrew can survive in a range of forest types, although most of the forests within its range are cool and damp. The long-tailed shrew is especially abundant in mountain forests, on ranges such as the Appalachians and Adirondacks. It makes its dens in cool rock crevices and under boulders and scree.
This shrews are often mistaken for smoky shrews, but long-tailed shrews tend to be more slender and have a longer tail.
Long-tailed shrews forage for food both day and night. They do not hibernate. Like most shrews, they lead a solitary life and chase away any shrew that comes near. A long-tailed shrew must eat twice its body weight in food every day to stay alive. The diet consists of insects, spiders, centipedes and other invertebrates, as well as plant foods such as seeds.
Distribution: Eastern North America.
Habitat: Damp forest.
Food: Invertebrates and plants.
Size: 4.6 - 10 cm (1.75 - 4 in); 4 - 6 g (0.1 - 0.2 oz).
Maturity: 4 months.
Breeding: Several litters of about 5 young produced between April and August.
Life span: 2 years.