“Dolphins often display a playful attitude which makes them popular in human culture” (Science World Kids.) In this article I will talk about what dolphins eat, how they sleep, what their environment is and others 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 "cetacean" means celus in Latin and kelos in Greek, both of which mean large marine animals (or creatures). There are thirty-two types of dolphins. One type is: the bottlenose dolphin (it is blue-gray with a very white dorsal fin and belly. It weighs an average of 350 pounds and its length is about nine feet). The average length of the common dolphin is eight feet and weight is approximately 165 pounds. The upper body is dark blue or black and the underside is white. It also has golden 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 Dolphins Dolphins are natural enemies of sharks. Larger sharks (such as great whites) normally eat smaller dolphins because they are easier to prey on. 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 staging attacks on other cetaceans. How dolphins sleep Dolphins sleep near the surface...... center of the map ...... Habitat and distribution of dolphins." Habitat and distribution of dolphins. Np, nd Web. November 6, 2013. "Dolphins of river." Np, nd Web. November 6, 2013. "All about dolphins." bahaviors." Dolphin Smart. Np, nd Web. November 13, 2012. “Wild Dolphin Bahaviors.” Dolphin Smart. Np, nd Web. November 13, 2012. "What is echolocation?". What is echolocation?. Np, 2 Web. 18 Nov. 2013. .