Some species of caterpillars have more than 4000 muscles in their tiny cylindrical bodies, with the average number being around 1500 muscles. That is more than twice as many muscles as humans have in their bodies, despite being roughly the size of a human being’s pinky toe. Humans have 639 muscles in their bodies. Caterpillars have so many muscles because of their unique form of transportation. To move, they must contract and elongate their many muscles, slowly moving in the desired direction.