Despite Risso’s dolphins having an estimated abundance of slightly more than 7000 individuals in Hawaii, they are very rarely seen in Hawaiian waters. They are found only very far from shore in deep waters reaching over 13,000-15,000 feet in depth.
The species is thought to forage primarily at night on squids but little is known about Hawaii’s Risso’s dolphins. They have a bulbous head and coloration can be any shade of brown, gray or almost dominated by white scarring that accumulates over the lifetime of the animal.
These animals have a robust body with a tall dorsal fin. In Hawaii an animal that stranded off of Maui in November of 2013 had a plastic bag in its esophagus. Risso’s dolphins are clearly not immune to the far reaching impacts of marine debris.