Bottlenose dolphins up close
Dolphins are often among people's favourite animals and none is more familiar that the bottlenose dolphin. Dolphins are very intelligent animals that display complex behaviours, some of which are aggressive and seem to contradict the image created by their 'permanent smile'.
Like most dolphins, bottlenoses feed on squid, shrimp, eels and a wide variety of fish. Although they hunt mainly in coastal waters, they also prey on bottom-dwelling and offshore fish. Their small, sharp, conical teeth are arranged in rows, which is typical of fish-eaters. Bottlenoses often hunt in teams and it's thought that they use sound to communicate to each other while pursuing prey.
Bottlenose dolphins are common in both the Atlantic and temperate Pacific oceans, being found in tropical and temperate coastal waters.
Dolphins are extremely social animals and live in groups called pods. These are usually made up of 1-10 dolphins in coastal regions, and 1-25 in offshore waters. Group structures are quite open, so an individual may leave or enter a particular pod several times.
The young tend to stay with their mothers after they reach adulthood, although males may join other pods to mate, often returning to their original group later on. Despite heavy competition for mating access to females, bonds between males appear to be strong. Male-female and male-calf bonds seem to be much weaker.
Dolphins are among the most vocal of mammals. They have excellent hearing and communicate with each other using a wide variety of sounds including whistles and clicks. They may even use a specific whistle to identify each other - the equivalent of a name.
Dolphins are typically perceived to be gentle creatures, but there is another side to their behaviour. Aggressive displays such as jaw-clapping, physical contact and scratches inflicted by sharp teeth are often used to determine and reinforce dominance hierarchies within a dolphin group.
Dolphins use sound to locate objects - a technique known as sonar or echolocation. Sound travels through water more efficiently than light does, so it is easier to hear than to see.