The world's fastest land animal (again: relative to its size) is Paratarsotomus macropalpis, a sesame-seed-sized mite native to southern California. Scientists recently clocked P. micropalpis traveling 322 body lengths per second – which, to scale, would be like a person running 1,300 miles per hour.

Via NatGeo:

The previous record-holder, the Australian tiger beetle, travels at 171 body lengths per second. By comparison, the cheetah—the fastest land animal overall—can move at only about 16 body lengths per second. (Related: "Cheetah Breaks Speed Record—Beats Usain Bolt by Seconds.") The fastest known human, Usain Bolt, covers a little more than 6 body lengths per second.

...1the team's findings also reinforce a scientific theory called scaling, which says that relative speed increases as an animal's body mass gets smaller. The theory holds that the smaller an animal gets, the less force it needs to move fast. And less force means not much need for muscle.