The Greyhound is a dog that has been bred for coursing games and greyhound racing. They are tall, muscular, and smooth-coated, with long tails and tough feet. The Greyhound is a gentle and intelligent breed whose combination of long, powerful legs, deep chest, flexible spine, and slim build allows it to reach average race speeds exceeding 40 mph. They can reach a full speed of 43 mph within 98 ft, traveling at almost 66 ft/s.

Source: Wikipedia