Risso’s dolphins (Grampus griseus) are medium-large oceanic dolphins occasionally seen in the deep offshore waters of Mirissa, Sri Lanka. Known for their unique grey colouring, scarred skin, and social behaviour, these dolphins are a fascinating species for marine enthusiasts and researchers.
Mirissa offers ideal conditions for Risso’s dolphins due to its deep pelagic waters, abundant squid and small fish populations, and warm tropical currents. Their presence contributes to the diverse cetacean biodiversity of southern Sri Lanka.
The species observed in Mirissa is the Risso’s Dolphin (Grampus griseus), a pelagic dolphin species distinguished by:
Risso’s dolphins are resident and migratory in tropical and subtropical oceans, including the Indian Ocean, with Mirissa forming a key observation point for offshore sightings.
Risso’s dolphins are attracted to Mirissa because of:
These factors make Mirissa an ideal location for observing their natural behaviour and feeding strategies.
Risso’s dolphins are larger than many other dolphin species, but smaller than pilot whales, with a robust body built for endurance and deep diving.
Their size allows them to:
This combination of strength, endurance, and agility makes them highly adapted to pelagic life.
These distinctive patterns make Risso’s dolphins easily distinguishable from other dolphin species.
Their unique head shape and scarring patterns are key identification markers.
Risso’s dolphins are identified by their size, rounded head, and scarring, distinguishing them from other local dolphin species.
Mirissa’s deep offshore waters support their primary prey, making it one of the few reliable observation areas.
November to April
May to October
Although sightings are occasional, experienced guides can locate pods in deeper waters during optimal months.
Guides tourists and researchers to high-probability locations
Risso’s dolphins prefer pelagic, deep-water habitats, distinguishing them from more coastal dolphin species like bottlenose or spinner dolphins.
Their social cohesion and unique surface behaviour make them fascinating for whale-watchers and marine researchers alike.
No. They are occasional visitors to offshore waters, but sightings occur, particularly during calm months.
By their large rounded head, light grey to white body, extensive scarring, and tall mid-back dorsal fin.
Yes. They are highly social and usually travel in pods of 5–30 individuals.
Yes. Observations are safe when boats maintain respectful distances and follow dolphin-watching guidelines.