The northernmost examples of this species were until recently thought to be a separate species, the Gaspé shrew (
S. gaspensis) inhabiting the Gaspé Peninsula and Cape Breton Island. However, a 2004 study indicated that the two species were conspecific, with the long-tailed shrew exhibiting a
cline towards a smaller size at the northern edge of its range. When they were regarded as separate species, the Gaspé and long-tailed shrews inhabited similar habitats, but were thought to be
sympatric species with adjacent ranges. They are now generally accepted to be the same species, with
S. gaspensis a junior synonym, not a subspecies. ==References==