Bottlenose dolphin
Physical description
The bottlenose dolphin is possibly the best recognised of all dolphins. Young are born pale grey in colour becoming a uniform dark grey at maturity, with the underside staying white.
They have a prominent ‘bottle’ shaped beak and a curved dorsal fin which, like all dolphins, is located on the centre of the back. In temperate seas, as Manx waters are, they can reach a length of 4 metres (13ft) , whereas in the tropics they are distinctly smaller, measuring only 2.5 metres (8ft).
Manx Distribution
Bottlenose dolphins are predominantly a winter visitor to Manx waters and can be seen between October and March. If you see dolphins around the Isle of Man during the winter, it is unlikely to be any other species. They are occasionally seen during the summer months, but typically in smaller pods. Through photo-identification work and collaboration with the Sea Watch Foundation, we know that many of our bottlenose dolphins spend the summer in Cardigan Bay, Wales.
Bottlenose dolphins are generally seen along the east coast, where they often stay close inshore and can be observed easily from land creating lots of disturbance. They are typically seen anywhere from Ramsey Bay to Langness, but may occasionally be seen on the west coast from Niarbyl or Peel.
In Manx waters, bottlenose dolphins are highly gregarious and hang around in large numbers. It is not uncommon to see more than 100 individuals stretched across the Manx coast, made up of a number of smaller sub groups containing around 20 animals. In other coastal areas of the British Isles, such large pod sizes is unusual.
It is clear the Isle of Man provides an important winter feeding ground for Irish Sea bottlenose dolphins, and more photo-identification work during winter months needs to be done to establish where else they are coming from. The windy weather makes data collection during the winter a real challenge and is our main obstacle when obtaining photographs.
Worldwide distribution
Bottlenose dolphins are primarily coastal but also occur in pelagic waters. They have a worldwide distribution and can be found throughout temperate and tropical waters, but not the polar regions.
Behaviour
Bottlenose dolphins are large, powerful and playful. They exhibit a wide variety of behaviour, often creating plenty of disturbance and white water as they surface. Behaviour can include bow riding, tail slapping, breaching and fast swimming. They are inquisitive and are often seen interacting and bow riding with boats. Being such an intelligent species, they have spare time to make up games, like this individual who was having a great time playing with some seaweed in Peel. Bottlenose dolphins have also been seen to play ‘football’ with jellyfish, using their beak and tail to throw the jellyfish through the air.
Feeding
The diet of a bottlenose dolphin is varied and they consume a wide variety of fish, cephalopods and crustaceans. Preference is for fatty fish like sea bass and sea trout, but they will also predate on smaller fish species such as herring and mackerel. They are not fussy eaters and if hungry will even take starfish and crabs.
Bottlenose dolphins across the world alter their foraging activities to suit their habitat; examples include driving fish onto a shallow beach at low tide, trapping the fish on the sand. Other examples include the formation of mud circles using the tail fluke, resulting in a net of mud to trap fish inside. The species is highly intelligent and these unique behaviours are taught down the generations of a small pod, ensuring these skills carry on in to the future.
Report a Sighting
Have you seen a bottlenose dolphin in Manx waters? Report your sighting to us.