Some dogs are bred to sit on the laps of royals, while others were bred for speed, athleticism and agility.
Whether it's the stunning endurance of the saluki, the sprinting genius of the greyhound, or the surprising speed of the tiny Jack Russell, these dogs have serious acceleration and top speeds.
These are the 10 fastest dogs in the world.
Fastest dog breeds
Greyhound
Top speed: 45mph
The thoroughbred of the canine world, greyhounds are widely recognised for their speed, as they have become champion sprinters in the canine world – and have been bred for racing since the 18th century as a result. Greyhounds aren't just sprinters though; they also have endurance, able to maintain high speeds. They can reach top speeds in about six strides.
Saluki
Top speed: 42mph
Salukis have been bred to chase rabbits, and have evolved to chase and catch prey over long distances and difficult terrain. They are better at long-distance running than greyhounds, and can cover several miles at top speeds.
Sloughi
Top speed: 42mph
It's a fairly rare breed, but the sloughi is a quiet and sensitive dog that is also extremely athletic. Sometimes nicknamed the 'Arabian greyhound', the elegant sloughi originated in North Africa and is a lean dog like its greyhound relatives.
Afghan hound
Top speed: 40mph
Yet another tall, graceful sighthound on our list of fast dog breeds! One of the biggest dog breeds in the world, Afghan hounds are famed for their long flowing locks, which hide their long legs and lean body.
Hungarian vizsla
Top speed: 40mph
The vizsla was bred for hunting, pointing and retrieving, with a muscular build that gives them greater stamina than the leaner dogs featured here. Unlike greyhounds, which prefer to have short blasts of exercise, viszlas can go all day – and needs long bouts of daily exercise. Despite their energy, they are gentle in nature.
Jack Russell terrier
Top speed: 38mph
Their legs may be small, but these little guys move quickly. Jack Russells are considered to be the fastest small dog breed, and for good reason, with top speeds at the upper end of the 30mph range. Best at short bursts of energy, these terriers were bred to hunt foxes, and are tough, sturdy dogs.
Dalmatian
Top speed: 37mph
The Dalmatian is a muscular, athletic dog, less lean than the other sighthounds. They were bred as runners though, used to run alongside carriages to protect them from the threat of highwaymen. They therefore have great speed and endurance.
Whippet
Top speed: 35mph
The whippet is known for its agility and speed, descending from the greyhound. They have the same S-shaped silhouette and long, willowy legs. As with greyhounds, they'll sprint happily and then sleep for the rest of the day, resting up after their short bursts of energy.
Borzoi
Top speed: 35mph
Another dog bred to hunt, the Russian borzoi dog is a sighthound with speed and agility at its disposal. Despite their heritage of hunting wolves, the borzoi is of calm and gentle temperament, and a great family dog for those who are up for a dog who needs a lot of exercise.
Doberman
Top speed: 32mph
The Doberman pinscher has long been used as a security and police dog, thanks to its speed, athleticism and agility.