A big, blunt-headed dolphin that gets whiter every year, because its skin keeps the scars of a life spent wrestling squid and sparring with its own kind. In 2025 a drone filmed more than a thousand of them off Cabo San Lucas.
A large, robust dolphin with no beak: the head is rounded and bulbous, with a vertical crease down the front. The dorsal fin is tall, curved and sickle-shaped, set in the middle of the back. Calves are dark and nearly unmarked, but adults are covered in white scratches and round marks, and older animals can look almost white, especially just under the surface.
Risso’s dolphins live in deep tropical and temperate waters around the world, from 64°N to 46°S, usually over the continental slope and in the open ocean. In Mexico they occur in the Gulf of California and around Baja California Sur. A 1993 NOAA survey of the eastern Pacific and the Gulf of California recorded them often, while later research cruises inside the Gulf saw them only once in spring, probably because they keep a low profile at the surface and travel in small groups.
They eat mainly squid, plus octopus, cuttlefish, krill and some fish such as anchovies, and they feed mostly at night. They have no teeth in the upper jaw and only two to seven pairs of peg-like teeth at the front of the lower jaw. Groups usually hold 10 to 30 animals, but they can travel alone, in pairs or in gatherings of hundreds or thousands.
Risso’s dolphins lighten as they get older because their scars don’t get pigmented again. A study that followed 61 dolphins in photos over 15 years used skin appearance to estimate age and found they may live more than 45 years.
Source ↗The same study found that adult females are less scarred than males. The scratches are tooth rakes from other Risso’s dolphins; the round marks come from prey and parasites.
Source ↗Risso’s dolphins usually have no upper teeth at all, only two to seven pairs of peg-like teeth at the front of the lower jaw, which is enough for soft prey like squid.
Source ↗In 2025 a drone filmed a pod of more than 1,000 Risso’s dolphins off Cabo San Lucas, a sighting described as exceptionally rare.
Source ↗A NOAA survey in 1993 found Risso’s dolphins often in the Gulf of California, but later spring cruises recorded only one group: their quiet surfacing and small groups make them hard to spot.
Source ↗Before diving they usually take 10 to 12 breaths, 15 to 20 seconds apart, and often show their tails. They can stay down for 30 minutes.
Source ↗Risso’s dolphins are deep-water animals, so off Los Cabos they are an occasional sighting offshore rather than something you see on every trip. Small groups often surface quietly and then disappear on long dives, which makes them easy to overlook. Once in a while they show up in huge numbers: in 2025 more than a thousand were filmed by drone off Cabo San Lucas.
Enjoy them from the boat: slow down, keep a steady course, and never chase a group or drive between the animals. Let them come to the boat if they want to, never feed them or try to swim with them, and keep lines and lures clear while they’re around.
| Mexico (NOM-059) | Subject to special protection (Pr) |
|---|---|
| Ley General de Vida Silvestre, art. 60 Bis | No extractive use or possession of any marine mammal, except authorized research and conservation |
| Whale-watching rules (NOM-131) | Do not apply: NOM-131 covers only baleen whales and the sperm whale |
| CITES | Appendix II |
| IUCN Red List | Least Concern (2018) |
The bottlenose dolphin is plain gray and has a clear short beak, while Risso’s has a blunt head with no beak and a scarred, pale body. The short-finned pilot whale is black with a low, broad dorsal fin set about a third of the way back from the head; Risso’s dorsal fin is tall, sickle-shaped and in the middle of the back.
Yes, but not often. They live over deep water offshore, and in 2025 a pod of more than a thousand was filmed off Cabo San Lucas.
Their scars don’t regain color, so they build up over the years. The scratches come from the teeth of other Risso’s dolphins, and the round marks from prey such as squid and from parasites.
Globally they are Least Concern on the IUCN Red List, but in Mexico they are subject to special protection (Pr) under NOM-059, and no marine mammal may be captured or kept.
Top illustration: Top Anglers. Photos: iNaturalist contributors, credited on each photo.
Our charters leave the Cabo San Lucas marina every morning. From $799 with license included.
