Monday, October 4, 2010

Water Shrew


DESCRIPTION: The Water Shrew is the largest long-tailed shrew in New England. It measures 144-158 mm (5.7~.2 in) in length, with its long tail accounting for more than half of its total length; and weighs from 10 16 g (approximately 1/3 oz), The unique feature of the Water Shrew is its big "feathered" hind foot. The third and fourth toes of the Water Shrew's hindfeet are slightly webbed, and all toes as well as the foot itself have conspicuous stiff hairs along the sides. Both the webbing and the fringe of hairs increase the Water Shrew's swimming efficiency.

The male and female Water Shrew are colored alike, equal in size, and show slight seasonal color variation. In winter, the Water Shrew is glossy, gray black above tipped with silver, and silvery buff below, becoming lighter on the throat and chin. It has whitish hands and feet, and a long, bicolored (ie.lighter beneath, darker above) tail covered with short, brown bristles. In summer, its pelage (fur) is more brownish DeGraaf. Richard M. and Rudis. Deborah D. above and slightly paler below, with a less frosted appearance. The New England Wildlife-Habitat Natural spring molt occurs during late May and early June; the autumn molt takes History and Distribution General Technical place in September. The color of immatures is much like that of adults.

SIMILAR SPEOES IN MASSAOfiJSEJTS: Five other species of shrews inhabit Massachusetts: the Masked Shrew (Sorex cinereus), Smoky Shrew (Sorex fumeus), Rock Shrew (Sorex disWr), Pygmy Shrew (Sorex hoyi), and Short-tailed Shrew (Blarina brevicauda). The Water Shrew is distinguishable from all of these because it is the only long-tailed shrew that has long hairs along the margins of its hind feet.

HABITAT : The Water Shrew is aptly named, for seldom is it found more than a few yards from the nearest water -a spring. a mountain lake, or, most commonly, the banks of a swift rocky-bedded stream usually near boreal or mixed forest. It prefers heavily wooded areas and is rarely found in marshes that are devoid of bushes and trees. It may be found in beaver lodges and muskrat houses in winter.

LIFECYCLE & BEHAVIOR: The Water Shrew is secretive and elusive, seeking cover along the waterways. It lives in bankside burrows, the entrance often concealed deep between boulders or between the gnarled roots of a leaning streamside hemlock. Small surface runways are usually found under cover of bank overhangs, fallen logs, brush piles or other debris. The Water Shrew makes it own runways but also uses those of mice and moles. The Water Shrew is active throughout the year at any time of the day or night, with peaks of activity at sunrise and sunset. It has periods of deep slumber, but during its waking hours it is extremely active, foraging excitedly for short periods, darting rapidly over the ground, traveling through subsurface tunnels, or burrowing through snow.

FEEDING:The Water Shrew feeds primarily on aquatic insects, chiefly mayflies, caddis flies, stone flies, and other flies and beetles and their larvae; although snails, flatworms, smaIl fish and fish eggs may also be eaten when available. Because the eyes of the Water Shrew are poorly developed, it uses its keen senses of touch, hearing, and smeIl when foraging. Foraging takes place both under and on top of the water. Prey is located underwater entirely by touch. The long whiskers located on either side of the shrew's head are extended stiffly out to the sides while the animal is casting for prey. It is speculated that water vibrations from the shrew's intended victim may alsoaid in guiding the Water Shrew to its prey.

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