Cheetahs need to be fast because their prey is fast 4
5 CHAPTER 1 A Cheetah Running crosses the A flash of tan and black spots open field in Kenya A cheetah chases its prey Its front legs reach forward Its strong back legs push off the ground A cheetah's legs make its body spring forward
6 Pronghorns reach speeds up to 55 miles per hour 89 km h Cheetahs are the fastest running mammal They can run in bursts at more than 70 miles per hour 110 km h But their speed usually lasts less
7 than 60 seconds In North America pronghorn antelopes are not as fast as cheetahs But they can run long distances faster than any other mammal Moving Their Muscles Mammals live in every habitat They walk climb swim and crawl Land mammals can weigh less than 1 pound 0.5 kg or more than 7,000 pounds 3,200 kg Some mammals have two legs Others have four Mammals with four legs are usually faster runners Mammals use muscle movement to get around They use energy to tighten their muscles Once tightened the muscles pull or push on the bones they are connected to
