Dolphin swimmers

Dolphins propel themselves by up and down movements of their tail flukes. They use their flippers for steering, turning and slowing down. The average dolphin swims at a rate of between 5 and 15 kilometres per hour. If they are being chased they are capable of swimming much faster to above 40 kilometres per hour.

Different dolphin species prefer different water temperatures. The Common Dolphin for example lives in warm waters whereas Belugas and Orcas can survive in arctic water temperatures. A dolphin's core body temperature is 98ºF whilst the outer body temperature is usually cooler. They have a thick layer of fat, called blubber, just beneath the skin which holds in the heat and keeps out cold.

Dolphins can slow down their hearts thereby using less oxygen than other animals. When diving deep for food, their lungs collapse and the heartbeats become even slower, enabling them to adjust to the greater pressure. They can control where oxygen is sent in their bodies. When they dive they send oxygen to the important brain and heart. Oxygen is stored in their blood and muscles.

Dolphins jump for a number of reasons. Sometimes it is to loosen tiny animals that cling to their skin, sometimes to travel faster or see further, at other times it is to confuse and herd fish they are chasing. They also jump when playing and having fun.