A chimp would never be able to throw a fastball, or anything even close to a fastball, and that seemingly weird fact helps explain why humans came to rule the animal kingdom, says a new study in Nature. Researchers say that early humans—Homo erectus, to be exact—developed the ability to throw about 2 million years ago, thanks to a handful of anatomical changes, reports the Washington Post. Among other things, we got longer waists, lower shoulders, and the ability to cock an arm way behind our back for extra power. (The researchers studied the motions of college pitchers to zero in on key factors.)
These changes allowed humans to become great hunters, providing the ability to take down big game with a well-aimed spear. Hunting “really did have a tremendously profound effect on who we are," says the lead researcher. The study shows how the anatomical changes dovetailed with a fossil record that shows how hunting intensified about the same time, reports the Boston Globe. ("I throw, therefore I am," is how Globe writer Carolyn Johnson sums things up.) Both stories also quote sports experts who say the findings could help them determine which pitchers are destined for greatness and which for the injured reserve.