“Dolphins often display a playful attitude that makes them popular in human culture” (Science World Kids.) In this article I will talk about what dolphins eat, how they sleep , their environment and other interesting facts.Dolphin SpeciesDolphins are a group of aquatic mammals called cetaceans. They are mammals because they are warm-blooded and give birth to their young. The word “cetaceans” means celus in Latin and kelos in Greek, both of which mean a large marine animal (or creature). There are thirty-two types of dolphins. One type is: the bottlenose dolphin (It is blue-gray with a dorsal fin and a very white belly. It weighs on average 350 pounds and its length is about nine feet.) The average length of the common dolphin is eight feet and his weight is around 165 pounds. Its upper body is dark blue or black and the underside is white. It also features gold stripes on the side of the dolphin and a dorsal fin. Another type of dolphin is the freshwater river dolphin. They have long snouts, small eyes, and can only dive for about a minute at a time. There are thirty-two species of dolphins, but only 12 of them are freshwater river dolphins that live in South America and northern and southern Asia. All river dolphins have large, broad pectoral fins and a movable neck. Enemies of DolphinsDolphins are natural enemies of sharks. Larger sharks (like the great white) normally eat smaller dolphins because they are easier to capture. They are also natural enemies of whales. Killer whales have eight to eleven teeth on the upper jaw and eleven to thirteen on the lower jaw. They are also very good at organizing assaults on other cetaceans.How dolphins sleepDolphins sleep near the surface...... middle of paper ......phin Habitat and distribution."Dolphin Habitat and Distribution . Np, nd Web. November 6, 2013. "River Dolphins." November 6, 2013. "What do dolphins eat?" Dolphin Smart. Np, nd Web. November 13, 2012. ". "Bhaviors of wild dolphins." Dolphin Smart. Np, nd Web. November 13, 2012. "What is echolocation?." What is echolocation?. Np, nd Web November 18.. 2013. .