An average dog can run at a speed of about 20 miles per hour.
Some breeds of dog can run much faster than others, and the fastest dog of all is the greyhound. A fully grown greyhound can run at the astonishing speed of about 72 kph (45 mph), that is, more than a kilometer a minute. Because greyhounds can run so fast, greyhound racing is a popular sport.
At a greyhound racing track, the dogs are put in a series of boxes called traps. Then an electriçally-driven imitation hare starts to move around a rail running beside the track. As the hare runs past the traps, the doors are released and in their excitement, the dogs rush out in pursuit. As in horse racing, people place bets on which dog will be first past the winning post.
The other fast breeds of dogs are Saluki, Afghan Hound, Vizsla, Jack Russell terrier, Borzoi, Whippet, Doberman Pinscher, and Dalmatian.