1 Relatively speaking
At up to 4m long the species is the biggest of the cetaceans we call dolphins, though it is actually more closely related to pilot and false killer whales than to its namesakes.
2 Battle scars
As they age, the grey, pale-bellied adult Risso’s dolphins accumulate scars from tussles with prey and other whales that can make them appear almost entirely white.
3 Shelf life
Risso’s dolphins prefer deep water beyond the edge of continental shelves, though a population of more than 100 animals frequents the shallow waters off Bardsey Island, north Wales.
4 Chewless wonders
Unusually for toothed whales, Risso’s dolphins have no teeth in the upper jaw and between only two and seven pairs in the lower. Unsurprisingly, perhaps, they swallow their squid prey whole.
5 Lord of the dance
The Scottish ceilidh dance Pelorus Jack is named after a Risso’s dolphin that was famous for escorting ships through a dangerous channel in Cook Strait, New Zealand, between 1888 and 1912.
6 French Connection
Risso’s dolphin is the sole member of the genus Grampus, which was once a common name for the orca. Its origin is mysterious – perhaps a contraction of grand poisson (‘big fish’).
7 French Connection II
The species is named after French naturalist Antoine Risso (1777-1845), who is also immortalised in the names of Risso’s lanternfish and many species of marine snail.