Field Guide/Mammals/Northern Water Shrew
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|Sorex palustris (American Water Shrew)|
Size: Length: 5 to 7 inches. (130 to 170mm)
Tail length: 2.2 to 3.5 inches. (57 to 89mm)Weight: 0.28 to 0.6 ounces. (8 to 18g)
Description: The coat appears black or dark grey, but it seems browner in the summer and blacker in the winter. Its hind feet are larger than its front feet, and its tail is darker on the top and lighter on the bottom. 
Similar Species: The Glacier Bay water shrew is sometimes classified as being an American water shrew, though the two are different species.
Range: The American water shrew can be found in Alaska, Canada, and the northern American states.
Habitat: American Water Shrews live in forests near streams or other water sources.
Diet: They mostly feed on aquatic insects but will also feed on land insects and vegetation. The water shrew will usually hunt any small creature that it can overpower. 
Activity: They are active during the day and night. For every half hour of activity the American water shrew spends one hour resting. The American water shrew is a solitary creature. 
Reproduction: The breeding season is from December to September. 1 to 2 litters are produced during each season with a litter of 3 to 10 offspring. They reach sexual maturity in the winter following their birth.
Lifespan: Their typical lifespan is 18 months.
Notes: Water shrews are relatively large compared to other shrews and are classified as long tailed shrews. They forage for food in the water and are able to swim in water all year long. Some water shrews have been seen walking on the surface of water as well. One suggestion as to how they can walk in water is that they are able to trap air bubbles between the hairs on their feet. They are aggressive creatures and fighting is common between both males and females. 
- Beneski, John; Stinson, Derek (1987), "Sorex palustris", Mammalian Species: 1-6, http://www.science.smith.edu/msi/, retrieved October 12, 2012
- Carmen, M. (2001), "Sorex Palustris", Animal Diversity Web, http://animaldiversity.ummz.umich.edu/accounts/Sorex_palustris/, retrieved October 9, 2012