Fleas accelerate faster than a launching space shuttle.

When a space shuttle launches from Cape Canaveral, its acceleration often maxes out around three Gs, aka three times the force of gravity. But when a flea launches itself off the ground and onto a dog’s back, the tiny pest accelerates at up to 100 Gs, dwarfing our humanmade rockets by comparison.

Fleas achieve such incredible acceleration speeds thanks to an elasticlike protein called resilin, located in pads atop their hind legs. As fleas prepare to jump, they contract their muscles, which causes energy to build up in that resilin, not unlike how someone in a sci-fi movie may charge a laser gun before firing. The fleas then push their legs outward, releasing all the stored energy and propelling it into the air with extreme force at distances of up to 50 times the insect’s body length — not quite all the way to outer space, but impressive nonetheless.