"The Long-tailed Shrew probably uses its long tail for balance when it is climbing among the rocks or boulders that are always present where it lives. It spends almost all its time underground, and was, until recently, thought to be uncommon (not being where biologists set traps). Its particularly narrow skull and buck-toothed incisors give it the ability to extract insects, spiders, and centipedes from rocky crevices. Individuals in the north of this shrew's range are much smaller than individuals in the south. In most mammal species, the opposite is true—northern individuals tend to be larger."

Links:
Mammal Species of the World
Click here for The American Society of Mammalogists species account