The larger of the two mantas, met at cleaning stations and identifiable from its belly markings.
Both destinations hold this species at cleaning stations, where it is reliable enough to be dived for deliberately. In the Galapagos the animals are often encountered in the current at the northern islands as well.
Distinguishing it from the reef manta comes down to the shoulder markings and the shape of the pale patch on the back; giant mantas also carry a dark mark on the underside around the gill slits that reef mantas lack. In the eastern Pacific the reef manta is absent, so an animal seen here is M. birostris by default — but the character is worth knowing for anyone logging in both oceans.
The ventral spot pattern is individually unique and is used for photo-identification. A flat, square-on shot of the belly is more useful to the research groups working both islands than a better-composed frame from an angle, and several accept diver submissions.
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.