Snarks are creatures of folklore in the Seven Kingdoms. The snarks are supposed to live beyond the Wall with grumkins, monsters used in nursery tales to frighten children. In derision of the apparent futility of the Wall and the mission of the Night's Watch, the snarks are often referenced as an improbable danger that is hiding in the haunted forest. They are known to be elusive and some may have beards.
Adults no longer believe in snarks and consider them imaginary beings, comparable to legendary animals and supernatural entities or the monsters which children's nurses warn them against. As a result, several attempts to seek aid against the danger of the Others are met with mockery which ridicules the messenger as also fearing "snarks and grumkins," which the speaker implies are similarly non-existent.