The genus Sorex includes many of the common shrews of Eurasia and North America, and contains at least 142 known species and subspecies. Members of this genus, known as long-tailed shrews, are the only members of the tribe Soricini of the subfamily Soricinae (red-toothed shrews). They have 32 teeth. In some species, a female shrew and her dependent young form "caravans", in which each shrew grasps the rear of the shrew in front, when changing location.