There are more than 32 different types of dolphins. A couple of examples are the bottlenose dolphins, a popular performing one in sea aquariums, and the common dolphin. There are also several freshwater dolphins in Asia and South America. The smallest kind of dolphin is less than 4 feet and the biggest dolphin is 10 feet long. 

           To find out if a dolphin is a male or female face a dolphin belly up. If you see a large slit in the middle and two little slits on the side, that's a female. A male has a long slit in the middle and a small slit above it.