Appearance 
There are considerable variations in size and coloration among the dolphin family. Some are very small; Hector’s Dolphin, the smallest, rarely grows larger than 4.75 feet (1.4 meters) long, and often weighs less than 100 pounds (45 kilograms). At the other end of the scale, Risso’s Dolphin can grow to over 12.5 feet (3.8 meters) and weighs as much as 1,100 pounds (500 kilograms); it is sometimes mistaken for a Beluga Whale. Some dolphins (including Commerson’s Dolphin, the Hourglass Dolphin, Peale’s Dolphin and the Dusky Dolphin) are recognized by their striking black-and-white patterns. Others (including the Atlantic Spotted Dolphin and the Rough Toothed Dolphin) are known for their spots.