Easily recognizable by their paddle-shaped snout, these shark-like river giants aren't actually related to sharks at all. In fact, paddlefish are harmless filter-feeders, opening their mouths to capture zooplankton.
There are two extant species of these creatures, the Chinese paddlefish and the American paddlefish (shown here). Unfortunately the Chinese paddlefish, which inhabits the Yangtze River, has been declared extinct. It was the larger of the two species, measuring as long as 9 to 10 feet in length. American paddlefish inhabit the Mississippi River valley and once inhabited the Great Lakes as well. They can grow to around 5 feet in length.