Global warming causes more extreme weather, rising oceans, melting ice caps, droughts, and animal extinction. Oh, and it might shrink you, too. A group of American scientists published a study Thursday in the journalScience that showed the prehistoric horse—in fact, the first horse—called Sifrhippus, shrank from an average of 12 pounds to about eight and a half some 56 million years ago, when the climate warmed up over thousands of years. Sifrhippus is much smaller than the modern horse—it's about the size of a cat. Scientists have known that mammals tend to shrink with global warming, but the study offered some of the first specific data on the phenomenon.