Sometimes I look at my cats, curled up in a tight circle in their beds and sleeping the day away, and I wonder how it can possibly be comfortable for them to contort themselves like that. I’d be one great, big ache if I tried such a thing.

While all four-legged mammals can curl up in a circle when they sleep, cats’ unique flexibility really shows the minute they wake up and stretch.

Why are cats so flexible?

As predators who pounce and chase their prey, cats evolved in such a way as to give them an extra-long stride, the ability to run almost 30 mph for short bursts, and the ability to jump as much as nine times their height from a standing position. Those evolutionary adaptations also gave them the ability to land on their feet (almost) all the time when they fall.

Cats’ extreme flexibility also makes it easy for them to clean all parts of their body, thus eliminating any odors that might cause them to be detected by other cats, larger predators, and potential prey.

What makes cats so flexible

It all starts with the spine. According to Dr. James R. Richards, director of the Cornell Feline Health Center, cats’ vertebrae – the individual bones that make up the spine – have extremely elastic cushioning discs between them, which allows cats to rotate their bodies as far as 180 degrees to the left and to the right, which means that a cat’s head and front legs can face the opposite direction from the hips and the hind legs. By contrast, typical humans can rotate their torso about 90 degrees either way.

The muscles, ligaments, and tendons that support the spine are also connected very flexibly. This flexibility allows cats to lengthen their stride by alternately extending and flexing the spine, and every running stride is about three times their body length.

The shoulders also play a part

Another factor in cats’ flexibility is that their shoulder blades are attached to the rest of the body only by muscles. Humans’ and dogs’ shoulder blades, on the other hand, form part of the joint that connects the upper arm or foreleg to the body. This allows cats to extend their running stride even more. Their loosely attached shoulder blades, along with tiny rudimentary collar bones, also allow them to squeeze into tiny spaces.

The next time you see your cat in some crazy, contorted position – or the next time you try to get your cat into a carrier and he slithers out of your arms like a demented snake – remember to thank his spine and shoulders for allowing him to do those things.