Skates are a family of flat-bodied rays found in warm and temperate seas. They are in the family Rajidae of the order Rajiformes.
Rays have broad, flattened bodies, with eyes located on the upper surface of the body while the mouth and gills are located on the lower surface. The upper surface of the body is dark colored, while the lower surface is light colored. This is called countershading and is a technique many marine animals use for protection as well as for predation. Countershading makes the animal almost invisible because when another animal looks down at them, they are camouflaged with the darkness of the sea bottom. When looked up at from underneath, the animal is camouflaged with the light from the sun. Great White Sharks use this technique for predation. Skates and rays swim using rajiform swimming.

* A picture of two skates taken by me at the New England Aquarium