Masked Shrew

About the Masked Shrew

The cinereus shrew or masked shrew (Sorex cinereus) is a small shrew found in Alaska, Canada, and the northern United States. This is the most widely distributed shrew in North America, where it is also known as the common shrew.

It is grey-brown in colour with a light grey underside and a pointed snout. It has a long tail that is brown on top and pale underneath with a dark tip. Its body is about 9 cm (3.5 in) in length including a 4 cm (1.6 in) long tail. It weighs about 5 g (0.18 oz). It has darker colouring than other shrews. Masked shrews can live up to two years, but, on average, only survive eighteen months.

In a long-term study done in Alaska, Yom-Tov and colleagues (2005) found that the masked shrew's body size contradicts Bergmann's rule. The study, done on 650 specimens and spanning from 1950 to 2003, examined body size in relation to ambient temperature. Measurements of body weight and the length of the tail, ear, hind foot, and body were taken. Results yielded that the masked shrew's body size decreased with high latitudes and with lower mean January temperatures, a trend that opposed Bergmann's Rule. It was suggested that this may be a coping mechanism... Wikipedia →