Bottlenose dolphin

Latin Tursiops truncatus
Manx Lheimmeyder mooar-tronnagh
Physical description

The Bottlenose dolphin is possibly the best recognised of all cetaceans. Young are born pale grey in colour becoming a uniform dark grey at maturity with only their underside staying white. They possess a long ‘bottle’ shaped beak and have a curved dorsal fin which, like all dolphins, is located in the centre of the back. In temperate seas, as Manx waters are, they can reach a length of 4 metres, whereas in the tropics they are distinctly smaller, measuring only 2.5 metres in length.

 Behaviour

Bottlenose dolphin (Tursiops spp.) - dive sequence Surface profile of common bottlenose dolphin (Tursiops truncatus) and Indo-Pacific dolphin (T. aduncus)

Bottlenose dolphins are large, powerful and playful. They exhibit a wide variety of behaviours often creating a lot of disturbance and white water as they surface. Behaviours can include bow riding, tail slapping, breaching and fast swimming. They are inquisitive and are often seen interacting with boats. These dolphins typically like to hang around in large groups in Manx waters and are often observed displaying highly active behaviours. This species has a reputation amongst scientists for bullying other smaller species; in the British Isles for example, this species has been known to bully and then kill Harbour porpoise individuals.

 Feeding

The diet of a Bottlenose dolphin is varied and they can eat a wide variety of fish and squid. Their preference is for species like sea bass and sea trout, but they will also hunt smaller fish species such as herring and mackerel and squid. They are not fussy eaters and if hungry will even eat animals like starfish and crabs. Like all dolphins, they echolocate to find their prey.

Group size

Bottlenose dolphins are highly gregarious and hang around in very large numbers; in Manx waters, it is not unusual to see over 100 individuals together. In other coastal areas of the British Isles, such large group sizes are unusual.

Abundance and distribution
Worldwide

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

Manx waters

Bottlenose dolphins are a winter visitor to Manx waters are mainly seen here from October to March. In the last 3 years we have also had sightings during the summer months, suggesting a change in their distribution. Through photo identification, we know that many of the dolphins seen here in the winter, spend the rest of the year in Cardigan Bay in Wales.

In Manx waters they are generally seen along the east coast, where they often stay very close inshore and can be seen easily from land. Ramsey Bay is a hotspot, as well as Laxey, Douglas Bay and Marine Drive.

Bottlenose dolphins breaching in front of Douglas Head

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