Why are cats so flexible?

Cats make their living in the wild as predators, and to be successful, they must be quick, powerful, and flexible. From a sitting start, they can spring up to nine times their height, and they can narrow their shoulders and chest to squeeze through almost impossibly tight spaces. In an eye’s blink they can right themselves in midair and land on their feet, and make sudden changes in direction while pursuing and capturing prey.

Cats are able to rotate their supple spines more than many other animals and can twist their bodies to a much greater extent. Cats’ vertebrae—the spools-on-a-string-like bones in the back—are very flexibly connected and have especially elastic cushioning disks between them. This limber spine allows cats to perform their elegant and graceful acrobatic feats, but it also contributes to their speed as runners. To reach top speed—about thirty miles an hour—cats lengthen their stride, and thus increase their speed, by alternately extending and flexing their backs. When the cat pushes off to start a new stride—with claws serving as spikes for traction—its body stretches to it maximum length, with every stride propelling the cat about three times the length of its body.

Moreover, the feline shoulder blade is attached to the rest of the body only by muscles, not by bone. This gives the shoulder blade tremendous freedom to move as the cat moves, extending its running stride even more. And unlike the long anchored collarbone we humans have, cats have tiny rudimentary collarbones that contribute to their ability to squeeze through tight openings.