The fastest dog
breed is Greyhound
. The greyhound can reach a full speed of 74 kilometers per hour (46 mph). Greyhound run at almost 20 meters per second for the first 250 meters of a race.
The key to the speed of a Greyhound can be found in its light but muscular build, large heart, and highest percentage of fast-twitch muscle of any dog breed, the double suspension gallop and the extreme flexibility of the spine.