Why do cheetahs run so fast? -Shanyu, 9, London, UK

Dear Shanyu,

Cheetahs are in really good shape. Not only are they good runners, but the actual shape of their body helps them move at incredible speeds.

As the fastest cats on the planet, they can reach 75 mph. Whenever I lace up my shoes and run, I can only reach about 30 mph. Us tabby cats are pretty quick, but not quick enough to outrun a cheetah.

The difference has to do with a cheetah’s amazing anatomy—everything from its head and skeleton to its muscles and feet.

That’s what I found out from my friend Bethany Richards. She studies veterinary medicine here at Washington State University and is president of the Zoo, Exotics and Wildlife Club.

cheetahs.drU“Cheetahs are so lean and just cool,” she said, recalling a recent safari in Africa, where she saw them running around.

She explained that a cheetah’s spine is very flexible. It’s more flexible than other cat spines. The spine is so flexible that it allows the cheetah to quickly move its two back feet ahead of its two front feet. Along with some unique hips, this movement helps the cheetah get more distance per stride.

This allows the cheetah to take four long strides each second. In fact, if you slow down video of a sprinting cheetah you see it spends more time in the air than on the ground.

A cheetah also has strong muscles to help the spine move. They are made of special fibers that are ideal for sprinting short distances. Their small skulls and narrow bodies keep the big cats aerodynamic as they zip through the air. They also use their big nostrils and big lungs to breathe as they run.

Richards explained that another important tool that cheetahs use for speed is their claws. Unlike the rest of us cats, cheetahs can’t retract their claws into their paws. This lets their paws work more like cleats. They can dig into the ground and not have to worry about swerving out of control at high speeds.

Cheetah populations are actually pretty small. They are an endangered species—they are at risk of extinction—and the mothers don’t have too many cubs. They need their speed to survive, Richards explained.

“It made sense that the fastest cats would be able to get to the best food to provide for their limited number of young,” she adds.

Of course, speed can be very useful when looking for dinner. But once the cheetahs catch their prey, they have to rest before eating. Scientists have also found that a cheetah’s agility—its ability to turn quickly and sharply while running—may be just as important to the hunt as speed. Put the two remarkable abilities together and you’ve got one cool cat.

Sincerely,
Dr. Universe