The Risso’s Dolphins of Monterey Bay

On a cold January morning in Monterey Bay, California, I boarded a whale watching vessel in the hope of catching an early glimpse of Grey whales, making their great southern migration. As the boat cast-off and began to trundle through the harbour, the rhythmic sound of engine knock was disrupted by the barking of California sea lions, waving us out from the harbour wall. The boat picked up speed and the cool air, heavy with moisture from the misty rain, chilled my face. I took another slurp of hot, strong black coffee.

California Sea lions at Monterey Bay Harbour mouth

It was not the best time of year or the best weather conditions for whale watching, and it certainly was not the best light for photography, as the heavy sky showed its full 50 shades of grey. Nevertheless, I was optimistic that I would see some marine mammals, and pelagic birds. We were not long into the journey when the first of the cetacea broke the surface. The Long-beaked Common dolphins had appeared.

Long-beaked Common dolphin follow the boat

Over the next few hours I was fortunate to spend some time with the Common dolphins, a couple of Grey whales and a young male Humpback whale. A sentence in a blog post doesn’t do justice to the enormous privilege that it is to experience an encounter with these ocean-going creatures.

As we turned south to cross the bay, a different species of dolphin appeared, as a group of fins simultaneously broke the surface. These fins belonged to a pod of Risso’s dolphin.

The high dorsal fin of the Risso’s dolphins breaks the surface

Despite taking many boat trips, in various countries, in search of marine wildlife I had never seen a Risso’s dolphin. This is a surprise due to the fact that these are one of the most widespread dolphins, occurring in both temperate and tropical waters.

The first thing that I noticed about the Risso’s dolphin was the high, curving dorsal fins. The next thing was what appeared to be a slower, more serene movement through the water. This was in clear contrast to the fast, erratic, shorter finned Common dolphins. As the Risso’s dolphins started to  break the surface, curiously, to study the contents of the boat above them, they reveal their blunt-nose faces.

Pod of Risso’s dolphins

The next thing that I noticed was the white face and mottled, streaked body, with colouration ranging from dark grey through to white. This is not the dolphin’s natural colour. Risso’s dolphins are born a uniform grey colour, but their diet of large, aggressive squid, who defend themselves to their certain death, with beaks and tentacles, leave them scarred with swirling lines and white skin. The older the dolphin, the whiter the colouration.


Risso’s dolphin is one of the largest dolphins, weighing in at over 1000 lbs. (500 kg) and growing to over 15 feet (3.8 m) in length. With the exception of the Orca, it is the largest dolphin to visit the Monterey Bay Area. This species usually spends its life beyond the continental shelves of the world, in the great open ocean. It is thought that up-swelling current over an uneven bottom of Monterey Bay, produces feeding opportunities that usually only exist further from shore. Recent estimates suggest that around 15,000 Risso’s dolphins live off the coast of Caifornia.


A Risso’s dolphin takes a look around

I never get tired of seeing dolphins, whether from a boat or the beach. It is always a special moment as they surface, that I cannot tear my eyes from. But so far, for me, the Risso’s dolphin has been my favourite dolphin sighting. It is definitely worth a trip to Monterey Bay, to see these unusual dolphins so close to the shore.

I didn’t head out on to the water that morning to see Risso’s dolphins and if truth be told, I didn’t know anything about them until I saw them. As it turned out, I couldn’t help but feel a little disappointed to leave behind these wonderful creatures to continue our hunt for their larger cousins, the great whales.

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I am a wildlife blogger and traveler, using images & stories to inspire wild connections.


  1. Great story and pictures! Last month, we left out of Moss Landing on our first whale watching trip. We were treated to a spectacular display by a group of demonstrative humpbacks. Unfortunately, we did not see any dolphins, but found several later, just cruising just beyond the breakers. Next time, I will look for Risso’s. They are a beautiful species.

    Liked by 1 person

  2. I find your description of the scarring especially interesting. My daughter is an expert in the study of (giant and colossal) squid, and they are the cause of the tremendous scarring that is commonly found on the heads of sperm whales, as they (the squid) are their (the whales’) favorite food. What a fascinating field of study!

    Liked by 1 person

    • Thanks for the comment, that is very interesting. We can only imagine the kind of battles that take place between whale and giant squid at incredible depth and pressure. Your daughter certainly has a fascinating field of study.


  3. Still imagining the battle for life that goes on between the Risso’s dolphins and squid. What incredible photos. The American Cetacean Society states that the size of the squid prey are unknown, but that beaks of squids that grow over 12 feet long have been found in the stomachs of stranded Risso’s. The dolphins have less than 7 pairs of teeth in the lower jaw and typically none in the upper jaw. Pods of Risso’s are usually 3-30 but “super-pods” of several thousand have been noted. While I love whale watching too, I am so glad you encountered this fascinating creature.

    Liked by 1 person

    • Thank you for the kind comment, and for contributing some great additional information for myself and others to learn from. It is amazing to imagine the battle between squid and dolphin, especially considering that the same battle usually takes place between Sperm whales and giant squid!

      Liked by 1 person

  4. It’s incredible to think that that coloration comes from squid attacks! Thank you for sharing that tidbit!

    I’ve just moved to southern Brazil, where we have numerous dolphin species. I don’t think the season is right for seeing them now, but I’m really hoping to catch a glimpse of a southern right whale dolphin later in the year. They look like orcas. Who knew?

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  5. Stumbled across this post while looking up information for a post of my own. Great write up. It is always so exciting when they are in the bay. I use to volunteer at the aquarium, and it was always exciting to see them off the deck during squid season. I would add one thing. While squid can leave some gnarly scars, they also get them from social interaction too. Dolphins of all kinds have a behavior called raking, and Risso’s seem to get many of their scars from other dolphins.

    Liked by 1 person

    • Hi Kristen, thanks for the kind, and informative comment. It is interesting to read about other ways that the Risso’s dolphin gets those distinctive scars. I’m glad that chance brought you to my blog! Best wishes, David


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