Risso's dolphins (Griseus grampus) competing at surface, Monterey Bay, California, USA

Risso's dolphins (Grampus griseus) surfacing in tight group showing scarred backs and fins. Canary Islands, North Atlantic.

Risso's dolphin (Grampus griseus) spy hop. National marine sanctuary, Monterey bay, California Pacific ocean, USA.

Risso's dolphin (Grampus griseus) surfacing at speed with natural scarring visible. Monterey Bay, California, USA

Pod of Risso's dolphins (Grampus griseus) travelling together. Monterey Bay, California, USA.

Risso's dolphin (Grampus griseus) three calves playing, fatal folds, teeth and tail fluke are clearly visible Monterey Bay, California, USA, Pacific Ocean, National Marine Sanctuary

Risso's dolphin (Grampus griseus) mother and calf, eye, mouth and fatal folds are clearly visible. Monterey Bay, California, USA, Pacific Ocean, National Marine Sanctuary

Risso's dolphin (Grampus griseus) close look at a calf surfacing next to its mother, fetal folds are visible. Monterey Bay, California, USA, Pacific Ocean, National Marine Sanctuary

Risso's dolphin (Grampus griseus) showing typical percussive behaviour: repeatedly leaping out of the water to land with a loud splash. Hebrides, Scotland.

Risso's dolphin surfacing to exhale (Grampus griseus) Azores, Atlantic Ocean