Cryptotis parva
least shrew

Cryptotis parva occurs throughout the eastern half of the U.S. south of the Great Lakes, in eastern and parts of central Mexico, in all of Guatemala, in the southern half of Belize, throughout El Salvador, in most of Honduras and in the northwest corner of Nicaragua.

In the northern part of its range, C. parva prefers grassy, weedy or brushy fields. In Central America it is more commonly found in damp or mesic areas, often bordering streams or lakes. Soil type does not appear to be a major factor affecting the presence of C. parva.

The fur of C. parva is short, dense and velvety. In winter the upper fur is brown to black and the underside is white. In summer the fur is paler. The zygomatic arches are incomplete. Like many other shrews, the teeth have brown pigment on the cusps. The teeth between the central incisors and the premolars have been termed unicuspids but the homologies of the anterior teeth are not well understood. A dental formula including the unicuspids is i 1/1 u 4/1 p 1/1 m 3/3. The deciduous teeth are lost prior to birth. Selected measurements are: total length, 67 to 103 mm; tail, 12 to 22 mm; hind foot, 9 to 13 mm; weight, 4 to 6.5 g. (Kurta, 1995)

One captive C. parva lived for 21 months. In the wild, they do not live nearly as long. (Kurta, 1995)

Unlike most shrews, C. parva seems to be somewhat social. Nests of as many as 31 individuals have been reported. Nests are small (less than 200 mm in diameter) and are typically lined with loosely piled leaves. Nests are connected to the surface by runways or burrows. Least shrews use burrows constructed by other animals or natural cracks in the ground or in buildings. They also dig their own burrows and pairs of animals have been observed digging burrows cooperatively. Burrows constructed by C. parva are approximately 25 mm in diameter. Although indivduals are active all day, activity peaks at night. Fighting has not been observed during encounters between least shrews, even when sharing the same piece of food.

Cryptotis parva emits a variety of high-pitched sounds, many of which seem to be involved in social behavior. Like all shrews, C. parva has sensitive vibrissae and keen senses of smell and hearing. (Kurta, 1995)

Least shrews eat a wide variety of invertebrates, including insects and bugs, earthworms, and snails and slugs. Plant material makes up a tiny portion of the diet. These animals seem to have a habit of opening the abdomens of grasshoppers and crickets and eating the internal organs.

Predators of least shrews include owls, red foxes, skunks, house cats, and snakes. (Kurta, 1995)

Where common, members of this species probably help control populations of harmful insects.

In the United States, least shrews are in no danger of extirpation (populations in Michigan, at the northern limit of the range of this species, are considered to be threatened). Populations in Central America may be threatened by habitat destruction, but insufficient information is available.

This species is known from Pleistocene deposits in the southeatern U.S., well within its current range. Cryptotis parva is the only species of this genus found north of Mexico.