Risso’s Dolphin
Deilf liath - Grampus griseus
How to identify
Risso’s dolphins are stocky and sturdy in appearance with a much lighter colour than any other dolphin in 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 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. 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 (such as Kenmare Bay) 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 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 (see video).
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
