This miniature marvel is an adolescent issus, a kind of planthopper insect and one of the fastest accelerators in the animal kingdom. As a duo of researchers in the U.K. report today in the journal Science, the issus also the first living creature ever discovered to sport a functioning gear. "Jumping is one of the most rapid and powerful things an animal can do," says Malcolm Burrows, a zoologist at the University of Cambridge and the lead author of the paper, "and that leads to all sorts of crazy specializations." 

The researchers believe that the issus—which lives chiefly on European climbing ivy—evolved its acrobatic prowess because it needs to flee dangerous situations. Although they're not exactly sure if the rapid jump evolved to escape hungry birds, parasitizing wasps, or the careless mouths of large grazing animals, "there's been enormous evolutionary pressure to become faster and faster, and jump further and further away," Burrows says. But gaining this high acceleration has put incredible demands on the reaction time of insect's body parts, and that's where the gears—which "you can imagine being at the top of the thigh bone in a human," Burrows says—come in.