Terriers are small but plucky dogs, bred in Britain to hunt and kill rodents, rabbits, foxes and otters. Many are adept at hunting underground in burrows, hence their name (from the Latin terra, meaning earth). Rat-catching breeds include the Jack Russell, the Border and the Yorkshire Terrier. Other breeds, such as the Staffordshire Bull Terrier, were developed for pit fighting.
As a largely nineteenth century invention, with most breeds being established in the latter part of the century, the terrier can be seen here as another of the recent technological innovations with which Stoker arms his heroes in their fight against the ancient forces of Dracula.