Synaptomys borealis, commonly known as the northern bog lemming, is a small rodent that inhabits the wetlands of North America. Its scientific name is derived from the Greek words synaptos, meaning "joined together," and mys, meaning "mouse." Some synonyms for Synaptomys borealis include the bog lemming, the northern bog mouse, and the swamp lemming. These terms all refer to the same animal, which has adapted to life in the damp, boggy environments of the northern United States and Canada. Despite being small and relatively unknown, Synaptomys borealis plays an important role in its ecosystem as a prey species for larger predators.