The majority of people are right-handed — somewhere between 70 and 90 percent, depending on which study's findings you accept. The other 10-30 percent are primarily left-handed or ambidextrous. Scientists aren't really sure why people favor one hand over the other, though theories range from genetic predisposition to trauma in the birthing canal.
More facts about human laterality:
- People who are right-handed are not necessarily right-footed. In fact, many right-handed people favor their left feet when playing sports, and vice-versa.
- People also have one eye that they favor over the other. This is called ocular dominance. About two-thirds of humans are right-eye dominant, and the other third are left-eye dominant or do not experience ocular dominance at all.
- Humans aren't the only ones with laterality; some animals experience it too. Many species of monkey are right- or left-handed, and rabbits, frogs and parrots all demonstrate "limb dominance" as well.