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Risso’s dolphin - Deilf liath - Dolffin Risso - Grampus griseus

How to identify

Risso’s dolphins (Grampus griseus) are stocky and sturdy in appearance with a much lighter colour than any other dolphin in Welsh and Irish waters. Their light grey / white bodies are often covered in scars, thought to be as a result of rough play fighting or during hunting. They grow up to 4 meters in length and can weigh 500kg, and with the short bulbous head and sickle shaped fin are one of the easiest to identify around Wales and Ireland.

Risso’s dolphins come in all shades of grey, to being almost completely white – Christina Winkler
Ecology, social dynamics and seasonality

Risso’s dolphin are found worldwide in temperate, subtropical, and tropical oceans and seas. Around the UK, they are most commonly seen around Scotland, Cornwall, Isle of Man, South-West and North-West of Wales and Ireland. They’re often seen in pods of 5-20 surfacing slowly but can also be energetic and playful breaching the surface. As they prefer deep water, they’re easier to see offshore, but in areas with steep drop offs they can be seen very close to the shore.

Risso's dolphins feed on crustaceans, fish and cephalopods including squid, octopus and cuttlefish, often feeding during the night as the prey moves to the surface of the water and is easier to catch.

Risso’s dolphins around Pen Llŷn

The best time to see the Risso’s dolphin from the shore is between May – October. The coast path at Uwchmynydd gives you the perfect viewing platform looking down the steep cliffs into the deep waters where pods occasionally pass by. Bardsey Island is one of only a few locations where they can consistently be seen from land and is the best place to catch a glimpse of them without a boat.

Risso’s dolphins along the Iveragh coast

Not as commonly seen as other species, Risso’s dolphins have been spotted from cliffs and headlands such as Bolus Head, Bray Head and Hog’s Head. The higher elevation makes it easier to spot their white bodies through the water.

Spot the Risso’s! The white bodies and dark dorsal fins of Risso’s dolphins makes them easy to spot and identify, even from greater distance (and with just a mobile phone camera) – Christina Winkler

Did you know…

… you can become a citizen scientist yourself and help identify where on Iveragh and Llŷn whales, dolphins and porpoises can be seen?

Iveragh Peninsula

The LIVE Project are partnering with the Irish Whale and Dolphin Group (IWDG) to record sightings of cetaceans along the Iveragh coast. Simply go to the IWDG website to log your sighting, and mention the LIVE Project after your name eg Suzie Smith LIVE Project

Download our handy guide here:

Download PDF • 169KB

Pen Llŷn

For sightings on Llŷn, a form can be filled out through the Sea Watch Foundation, strandings are reported through the CSIP, and for live strandings please contact the British Divers Marine Life Rescue on 01825 765546.


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