Northern Inuit dogs

The first season used Northern Inuit dogs, a type specifically bred for wolf-like appearance, to stand in for the dire wolves (the Stark's house sigil). However, since dire wolves are known to be much larger than normal wolves, real wolves were digitally composited into scenes for season 2. This strained the budget and the schedule, hence why there are only a handful of scenes with Grey Wind (Robb Stark's wolf), Summer (Bran Stark's wolf) and Shaggydog (Rickon Stark's wolf); Ghost, who belongs to Jon Snow, is shown in brief glimpses.