The clip below goes through several examples, including this one, which you can easily try for yourself. Place your arm on a flat surface. Then, press your thumb and pinky together and tip your hand slightly up. Do you see a raised band in your forearm? If so, you have a vestigial muscle in your arm.
10-15 percent of all people lack this muscle in one or both forearms. But don’t worry—the muscle makes no difference in grip strength. Several animal species—mainly those who use their arms or front legs to climb—still use this muscle.
Watch this video to see more examples of what we carry with us from our ancestors.
Fascinated by these evolutionary leftovers? Please share!