Nocturnal animals tend to have proportionally bigger eyes than humans do ... (Both are named after their relative shapes.) Cones work in bright light and register detail, while rods work in ...

presumably because color vision is less important at night and because cones are most effective in bright daylight. If the benefits of seeing dwindle to none, some animals lose their eyes altogether.

When disturbed, they flash their bulging red eyes and reveal their huge, webbed orange feet and bright blue-and-yellow ... Many of the animals that eat red-eyed tree frogs are nocturnal hunters ...