Dolphins are aquatic mammals; belonging to Order Cetacea. Cetus means a whale or a huge fish. There are around 90 living species in Cetacea divided into two groups.
- First group comprises toothed animals such as dolphins, killer whales; porpoise; sperm whale; beaked whale, narwhal.
- The second group comprises the whales which have filter feeder system.This group comprises blue whale and some other animals.
Thus, dolphins are toothed marine mammals. They have curved mouth that gives them a permanent smile. They vary in size from 5ft to 30ft. The food of dolphins is fish and squid. Dolphins use echolocation (the built in Sonar in dolphins) to locate their prey. At the same time, they also sometimes follow fishing boats, other whales, and birds to find their prey. Since they are marine Mammals; they are warm blooded animals.
Dolphins are considered to be highly social mammals which communicate with squeaks, whistles and clicks. They are also very playful and communicative.
- The smallest dolphin is Maui dolphin, which is around 5 feet long. The largest dolphin is Orca, which can be around 30 ft long.
- Dolphins swim alongside ships, which is basically a way to have fun. This is called bow-riding. The waves created by boats and ships propels them forward and they keep twisting and turning in water. When dolphins swim along and surf in the waves created by the back of boats and ships; it is called wake riding. Dolphins often leap in air when doing bow riding and wake riding.
- Dophins are semihemispheric sleepers; half of their brains go to sleep at a time so that they can keep breathing.