SHAAARK! Did you just get a mental image of a gaping mouth and pointy teeth? Think again. The roughly 500 known species of shark vary in size, shape, environment and diet.
Living shark species range from a few that could fit in your hand, such as the dwarf lanternshark, to a few you could fit inside, including the whale shark, which grows up to 40 feet long.
Angelsharks are nearly flat, like the rays and skates to which sharks are closely related, while sawsharks have a toothy snout that can be almost as long as their cylindrical bodies.
Sharks ply the waters of every ocean, from shallow, brackish estuaries to depths of nearly 10,000 feet.
Deep-sea dwelling Mitsukurina owstoni, the goblin shark, is the oldest living species among lamniform sharks, which go back about 125 million years and today include great whites, threshers and makos.
The first sharks evolved 400 ...
