A breed of large and powerful dogs, with long, smooth,
   and pendulous ears, and remarkable for acuteness of smell. It is
   employed to recover game or prey which has escaped wounded from a
   hunter, and for tracking criminals. Formerly it was used for pursuing
   runaway slaves. Other varieties of dog are often used for the same
   purpose and go by the same name. The Cuban bloodhound is said to be a
   variety of the mastiff.