The Greyhound Dog is not an aggressive dog, as some might believe, because of muzzles used during the race. Muzzles are used to prevent injuries caused by dogs cut each other during or immediately after a race, when the 'hare' has disappeared from view and dogs are no longer runs, but still excited. The thin skin of the Greyhound can easily copy a small cut of the teeth, so even a small skirmish can lead to penalties and time out of competition. Dogs with high prey drive occasionally use the outside lane, the owners know that the Greyhound has a tendency to chase small prey to protect the prey with the snout.
Contrary to popular belief, greyhounds do not need adults for long periods of daily exercise, because they are created for the race instead of resistance. Greyhound puppies that are not taught to use their energy, however, may be hyperactive and destructive if not given an outlet, and require skilled operators.