cinereus; aka common shrew
The second smallest shrew in
the world, behind the pygmy shrew, adult masked
shrews average just under 4 inches in total
length, including a tail of up to almost 2
inches, and weigh less than an ounce. The
slender, cylindrical body has short, velvety,
directionless fur that is brown above and
grayish-white below; the fur tends to be darker
overall in winter. The long, tapered head ends in
a flexible, tubular snout, with the narrow
nostrils located on the outer edges of the tip.
The small external ears are barely visible or are
completely hidden by the fur. The eyes are tiny,
the tail scantily haired, and the limbs short.
The most widely distributed shrew in North
America, the masked shrew is found throughout the
northern United States, most of Canada, and
Alaska. It occupies a diversity of habitats, with
the most common being open and closed forests,
meadows, river banks, lake shores, and willow
thickets. Habitat suitability depends on the
availability of water, and the highest population
densities can be found in moist environments.
Masked shrews also do well in disturbed habitats
such as those disturbed by fire or logging.
Habits and Behaviors
Although not strictly
nocturnal, the masked shrew is most active after
dark. Clouds and rain increase nocturnal
movement. It tends to stay under
cover and is therefore rarely seen. Active year
round, it will even tunnel through snow to
explore the surface.
Masked shrews consume a
variety of invertebrates including insect larvae,
ants, beetles, crickets, grasshoppers, spiders,
harvestmen, centipedes, slugs, snails, as well as
some seeds and fungi.
Breeding season extends from April to
November. Two to ten young are born after a
gestation of 19-22 days. Fine hairs develop at
about 10 days, the eyes open at 17-18 days,
weaning begins about day 20, and the young leave
the nest around day 30. A female may have up to 3
litters in one year. The average life span of a
masked shrew is less than 14 months.
genus & species Sorex cinereus
Animal Diversity Web http://animaldiversity.org/accounts/Martes_zibellina/
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