Destillat

Is there anything to back this claim up? The only dire wolves to have been described as huge at any point in the books were 1. The dead dire wolf who gave birth to them, and 2. Nymeria (possibly partly from exaggerated word of mouth, and/or from her bountiful diet [of corpses]). I didn't get the impression that we've seen them full grown, but I could be mistaken.