12 Things you learned in school that have since been proven wrong

Lemmings commit mass suicide

Lemmings do not commit suicide. However, this particular myth is based on some actual lemming behaviors. Lemmings have large population booms every three or four years. When the concentration of lemmings becomes too high in one area, a large group will set out in search of a new home. Lemmings can swim, so if they reach a water obstacle, such as a river or lake, they may try to cross it. Inevitably, a few individuals drown. But it’s hardly suicide.