| Dolphins are marine mammals found in all the | | | | identification mark. In some ocean dolphins, the |
| world's oceans, relatives to whales and porpoises. | | | | dorsal fin is hooked-shape instead of like a triangle. |
| River dolphins live in freshwater rivers and lakes. | | | | The male killer whales have very tall dorsal fins |
| They are intelligent and playful creatures and | | | | whereas in river dolphins it scarcely forms a ridge |
| friendly to humans.Dolphins have a sleek body | | | | on the back.Besides using eyes, dolphins can find |
| shape, which helps them to be good swimmers. | | | | their way by making clicking sounds, and listening |
| They have long snouts, a row of sharp teeth, and | | | | to the sounds that echo or bounce back to them |
| a blowhole for breathing on top of the head. They | | | | from their surroundings. This is called |
| feed on fish, squid, and other small marine | | | | echolocation.Under their skin, dolphins have a layer |
| life.Feeding dolphins at SeaWorld, OrlandoDolphins | | | | of fat called blubber. It insulates the dolphin so it |
| are social animals, and usually live and hunt in | | | | can keep warm even in cold water. The colder |
| groups. They communicate with each other with | | | | the water is where the dolphin lives, the thicker |
| sounds such as whistles, screeches, and clicks. | | | | the layer of blubber.BehaviorDolphins are social |
| Dolphins are often friendly to humans, riding on | | | | animals that live in schools of varying size; some |
| waves produced by boats, aiding lost swimmers, | | | | only have 2-5 dolphins while enormous schools of |
| and adapting to life in captivity performing tricks | | | | 1,000 or more have been found as well. A typical |
| and jumps.There are at least 40 different species | | | | school of bottlenose dolphins might be 10-20 |
| of dolphins. The one most commonly used in | | | | individuals.For food, dolphins hunt fish, squid and |
| amusement parks and performances is bottlenose | | | | other invertebrates; killer whales also feed on |
| dolphin, which has a 'built-in' smile formed by the | | | | other marine mammals, sea turtles, and birds. |
| curvature of its mouth. The killer whale, or orca, is | | | | Dolphins often hunt together, trying to catch |
| the largest member of dolphin family. | | | | schools of fish. They can use echolocation to find |
| Physical featuresDolphins have a sleek body | | | | prey in deep, dark waters.Dolphins make whistles, |
| shape, so as to offer the least resistance for | | | | clicks, and screeching sounds to communicate with |
| swimming. The two flippers located underside help | | | | each other, and for echolocation. In many species |
| the dolphin steer its course. The bones in these | | | | each individual dolphin makes a unique 'signature |
| flippers resemble human hand! The tail with flukes | | | | whistle'. Human-made underwater sounds, such as |
| provides the main swimming force.As mammals, | | | | used with sonar images, can interfere with |
| dolphins have to breathe air. They do so through | | | | dolphins' communication, and even injure tissues |
| a single blowhole on the top of the head. It has a | | | | used for hearing and air intake.Dolphins also help |
| muscular plug to keep water out of the lungs | | | | each other in various ways. If a dolphin is sick and |
| while diving. The head has a long snout. Dolphins | | | | can't raise to the surface to get air, another one |
| have a long row of conical teeth that are used | | | | supports it at the surface so it can breathe. Or, a |
| for catching and tearing prey - not for | | | | dolphin may stay near an injured or sick one as a |
| chewing.Different dolphin species vary a lot in size. | | | | companion. Dolphins also defend an injured one |
| The smallest one, tucuxi dolphin, is about 4 feet | | | | against a threat such as a boat.Male and female |
| (1.2m) long and weighs about 110 pounds (50kg), | | | | dolphin take part in courtship, which involves |
| whereas the enormous killer whales is over 30 | | | | playing, caressing, and 'songs'. Gestation lasts |
| feet (9-10m) long and weighs 12,000 pounds (5 | | | | about a year, and then a single calf is born. Calving |
| 500 kg).You've seen the gray ones, but dolphins | | | | usually occurs once every two years. Dolphin |
| can also be black or brown, and can have | | | | mother produces very high-fat milk for her young. |
| patterns of white or light colors.In the middle of | | | | The calf is weaned aroud 6 months to two |
| their back, many dolphins have what is called a | | | | years.Certain dolphin species live quite long, 50 |
| dorsal fin. It helps them to keep their balance. | | | | years or more, while the bottlenose dolphin and |
| Furthermore, each dolphin's dorsal fin is shaped | | | | common dolphin typically live around 20-25 years. |
| differently from the others. It's like an | | | | |