The folks at Argonne National Laboratory wanted to know how a caterpillar moves. So they built a tiny, custom-built caterpillar treadmill and blasted it with fancy x-rays, discovering that at least one species of caterpillar precedes each step with a thrust of its gut. According to NPR, the finding points to an entirely new mode of animal locomotion and could lead researchers to develop new robotic tools for exploration and medicine.