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Shrews: Soricidae

American Least Shrew (cryptotis Parva): Species Accounts

Physical characteristics: Just 2.2 to 3.1 inches (5.5 to 7.8 cm) in head to body length, this small shrew has a brownish gray back and whitish belly, a long snout, red-tinged teeth, and a tail that is no more than a third of the length of its head and body. It weighs from 0.1 to 0.3 ounces (4 to 8 grams). Its eyes are small and its ears are unnoticeable.

Geographic range: United States, extreme southeastern Canada, Mexico, and much of Central American to Panama.

Habitat: American least shrews are common in open, grassy fields, sometimes near a stream, but may also live in damp forests. This species spends much of its time in shallow tunnels it either makes itself or borrows from other animals.

Most shrews prefer to live alone, but two dozen or more adult American least shrews may share a burrow, where they click at one another to communicate. (Illustration by Emily Damstra. Reproduced by permission.)

Diet: Active day and night, year-round, they spend most of their time running about in search of food, which can include caterpillars, worms and other invertebrates (animals without backbones), small frogs and lizards, or bits of already-dead animals they find.

Behavior and reproduction: Least shrews are skittish animals that are mainly active at night, although they will also warily venture about during the day. Their brownish gray coloration, small size, and tendency to hide among grasses or underground helps them avoid their numerous predators, animals that hunt them for food, which include owls, skunks, snakes, and a variety of other animals. They make a variety of sounds, some of which may be used to help them find their next meal. Just as bats make high-pitched noises and listen as the noises bounce off objects and back to them, American least shrews may make clicking noises, and then listen for the bounced clicks to detect objects, like prey, in their surroundings. This ability to "see" objects with reflected sound waves is called echolocation (eck-oh-loh-KAY-shun).

Unlike most other shrews that like to live alone, several to sometimes even more than two dozen adult American least shrews may share a burrow, where they click at one another to communicate. They mate all year long in warmer areas of their range, but limit mating to spring, summer, and fall in cooler areas. The female has her young after a pregnancy of about three weeks in grassy and/or leafy nests built in the burrow. The litter size is usually three to seven, but may be as small as one or as large as nine. The babies stay with the mother for almost three weeks.

American least shrews and people: This shrew usually remains out of sight, but it can assist gardeners and farmers by eating crop-destroying insects.

Conservation status: Neither the IUCN nor the U.S. Fish and Wildlife Service lists them as endangered, but some states consider them to be threatened. Connecticut, for example, lists American least shrews as endangered because their habitat is rapidly disappearing. ∎

Additional topics

Animal Life ResourceMammalsShrews: Soricidae - Physical Characteristics, Behavior And Reproduction, Shrews And People, Conservation Status, American Least Shrew (cryptotis Parva): Species Accounts - GEOGRAPHIC RANGE, HABITAT, DIET