Bottlenose Dolphins are widely distributed in warm and temperate water throughout the world, although they are relatively uncommon around the UK coast. The Moray Firth dolphins are extremely important as they represent one of only two or three resident populations known to exist in UK waters and probably the only one in the North Sea. There are thought to be over 100 Bottlenosed dolphins living in the Moray Firth. Adults have a clearly defined beak and a tall sickle-shaped dorsal fin which curves backwards. They are between 3.1 and 3.8 metres in length, about twice as long as Harbour porpoises, and weigh between 180 and 300 kilograms. They typically live for 25 years, although animals as old as 50 years have been recorded. Females reach sexual maturity between the ages of 5 and 12, and may give birth to a single calf every 2 to 3 years, look out for newborn calves any time between March and September. The calf may be helped to the surface by its mother for its first breath of air. If the mother is weak, other female dolphins in the herd often look after her.