AnimalsInterestingThe mantis shrimp has 16 types of color receptors compared to humans' 3, but despite this they're actually terrible at distinguishing between similar shades. Scientists believe they use colors more like a barcode scanner than a camera.
BodyInterestingYour cornea has no blood supply at all — it gets its oxygen directly from the air, dissolved through your tears. It's one of the only tissues in the human body that is completely avascular. This is also why wearing contact lenses for too long can cause problems: they block oxygen from reaching the cornea.
