"Did you know that there are colors that humans can't see? Animals like the mantis shrimp can see a lot more colors than we can, which means that there are "secret colors" that we will never get to know about. Non 4-year-old explanation: the vast majority of humans see things in "channels" of red, green and blue. Some humans are lucky and are born with four "channels", called [tetrachromats]. Mantis shrimp see things in TWELVE different "channels", and can even see ultraviolet and polarized light."