Northern bog lemming

The northern bog lemming (Synaptomys borealis) is a small North American lemming. This is one of two species in genus Synaptomys, the other being the southern bog lemming.

They have cylindrical bodies covered with long grey or brown fur with pale grey underparts. There is a patch of rust-coloured hair at the base of the ears. They have small eyes, a hairy snout and a short tail. They have 16 teeth and their upper incisors are grooved. They are 13 cm long with a 2 cm tail and weigh about 30 g.