A large grey dolphin with a short thick beak. It passes rather than stays, and encounters are luck rather than planning.
Between 1.8 and 4 m and 136 to 635 kg. Plain grey, darker on the back, with no cape line, no stripe and no spots. The beak is short and thick and meets the melon at a clear crease. The dorsal fin is tall and curved and is usually notched, which is how researchers tell individuals apart.
Of the dolphins on this site it is the only one with no pattern at all, and it is the bulkiest. The pantropical spotted dolphin is the one it is mistaken for, because young spotted dolphins have not yet developed their spots: that species has a dark back sharply separated from pale flanks and a white beak tip, which the bottlenose does not.
The animals at Galapagos, Cocos and Revillagigedo are the offshore form — larger, darker and more heavily scarred than coastal dolphins. Coastal animals stay above 50 m; offshore animals feed at 200 to 500 m and have been recorded to 535 m. Encounters are bow-riding and fast passes in blue water, lasting seconds to minutes. It is not endangered. All three destinations prohibit pursuit and deliberate approach in the water.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.