Animals

The Bottlenose Dolphin is the most common and well-known dolphin. They live in warm and temperate seas all around the world, except in the Artic and the Antarctic Oceans. Bottlenose Dolphins have a grey color, that vary from dark grey at the top near the dorsal fin to very light grey and almost white or maybe even a pinkish color at the underside.

This makes them hard to see both from above and below when swimming. The elongated upper and lower jaws form what is called the rostrum and give the animals their name of bottlenose. The real nose however is the blowhole on top of the head, and the nasal septum is visible when the blowhole is open. Their face shows a characteristic “smile”. The “smile” does not mean that they are happy. They are unable to move their jaw in any other position.

Dolphins in warmer, shallower waters tend to have a smaller body than their cousins in cooler waters. For example a survey of animals in the Moray Firth in Scotland, the world’s northernmost resident population, recorded an average adult length of just under 4 m (13 ft). This compares with a 2.5 m (8 ft) average in a population of Florida. Those in colder waters also have a fattier composition and blood more suited to deep-diving.

The flukes (lobes of the tail) and dorsal fin are formed of dense connective tissue and don’t contain bones or muscle. The animal propels forward by moving the flukes up and down. The pectoral flippers (at the sides of the body) serve for steering; they contain bones clearly homologous to the forelimbs of land mammals.

In fact, recently, in Japan, a Bottlenose Dolphin was discovered to have two additional pectoral fins, or “hind legs”, at the tail, appearing to be about the size of a human’s pair of hands. Scientists believe that a mutation must have caused the ancient trait to reassert itself.