Tony Wu / Humpback whale (Megaptera novaeangliae) lying on its side while executing a series of pectoral fin slaps on ocean surface. Vava'u, Tonga, South Pacific.

Nick Hawkins / Galapagos green turtle (Chelonia mydas agassizi) swimming above sea floor with shoal of fish in background. Off San Cristobal Island, Galapagos.

David Fleetham / Humpback whale (Megaptera novaeangliae), mother and calf swimming just below surface in front of the West Maui Mountains. South of Lahaina, West Maui, Hawaii.

Nick Upton / Grey seal (Halichoerus grypus) pup aged one month, rubbing its head with its flipper, yawning and settling down to rest on a sandy beach, Norfolk, England, UK, January.

Tony Wu / Humpback whale (Megaptera novaeangliae) female with calf, pursued by males during heat run. Vava'u, Kingdom of Tonga. Pacific Ocean.

Nick Upton / Blind adult male Grey seal (Halichoerus grypus) 'Marlin' waving a flipper at the edge of a convalescence pool where he is a long-term resident, Cornish Seal Sanctuary, Gweek, Cornwall, UK, January. Mo...

Nick Upton / Adult female Common / Harbour seal (Phoca vitulina) 'Sija' waving a flipper in a pool where she is a long-term resident, Cornish Seal Sanctuary, Gweek, Cornwall, UK, January.

Gabriel Rojo / Southern Right whale (Eubalaena australis) breaching, Peninsula Valdes, Chubut, Patagonia, Argentina.

Tui De Roy / Galapagos sea lion (Zalophus wollebaeki) juvenile on beach, Galapagos

Frederique Olivier / Adelie penguins (Pygoscelis adeliae) wide angle portrait of two with larger group in background, Antarctica.

Nick Upton / Grey seal (Halichoerus grypus) pup resting on a sandy beach, stretching and rubbing its head with its flipper, Norfolk, England, UK, January.

Roy Mangersnes / Bearded seal (Erignathus barbatus) stretching flipper, on an ice floe, Spitsbergen, Svalbard, Norway, July.