Risso's dolphin (Grampus griseus) is a dolphin, the only species of the genus Grampus. Some of the closest related species to these dolphins include: pilot whales (Globicephala spp.), pygmy killer whales (Feresa attenuata), melon-headed whales (Peponocephala electra), and false killer whales (Pseudorca crassidens).[5]

Risso's dolphin[1]
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Size compared to an average human