Scientists tested eighteen reindeer with light, and found that their eyes responded to both visible light and ultraviolet.
When we are in a fairly dark room, or outside at night away from lights, we can still see, but we can't see the colors of things very well. Why is that?
Ever notice how a little cologne can be attractive, but too much is totally repellent? That principle is used by cycads, an ancient type of cone-bearing tree.
With three simple ingredients, a red, a green, and a blue spotlight, you can make any color of the rainbow. Learn more on this Moment of Science.
Learn about peripheral vision and color on this Moment of Science.
The back of your eye, called the retina, has two kinds of cells: rods and cones. In bright light the cones are what we use, while in dim light the cones are less active and the rods take over.