Risso's Dolphin
Grampus griseus
The 'Gray Ghosts' of the deep, Risso's Dolphins are famous for their battle-scarred skin and enigmatic, blunt-nosed silhouettes. These deep-diving specialists are the ultimate prize for coastal wildlife watchers and offshore explorers alike.
Quick Identification
Size
3 to 4 metres (10 to 13 feet) in length; weighing between 300 and 500 kg (660 to 1,100 lbs).
Colors
Adults are typically light grey to nearly white, covered in extensive white scarring; juveniles are darker grey or olive-brown.
Key Features
- Blunt, bulbous head with no distinct beak
- Deep vertical crease centered on the forehead
- Extensive white linear scarring across the body
- Tall, dark, sickle-shaped dorsal fin
When You’ll See Them
Geographic range
Where Does the Risso's Dolphin Live?
Risso's Dolphins have a vast global presence, spanning the temperate and tropical oceans of the world. They are native to the waters surrounding every continent except Antarctica, with core populations concentrated along the continental slopes of the North Atlantic and Pacific. While they are essentially citizens of the high seas, they are frequently sighted off the coasts of the United States, the United Kingdom, Japan, and New Zealand where underwater canyons draw them closer to land.
Basemap © OpenStreetMap contributors
Behavior
Risso's Dolphins are highly social marine mammals that typically travel in pods of 10 to 50 individuals, though "super-pods" numbering in the hundreds are occasionally seen. They form very stable social bonds, often segregated by age and sex. While they aren't as acrobatic or "bow-ride" as frequently as Bottlenose Dolphins, they are known for behaviors like breaching, flipper slapping, and "spy-hopping," where they lift their heads vertically out of the water to survey their surroundings.
These dolphins are expert deep-divers, capable of descending to depths of 600 metres (2,000 feet) to hunt. During the day, they are often seen "logging"—resting quietly at the surface—to recover from deep-sea foraging trips. Their interactions with humans are generally cautious; they rarely approach boats directly, but their distinctive scarred appearance makes them a favorite for offshore wildlife photographers.
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Camera Tips
Capturing a Risso's Dolphin on camera requires a different approach than typical backyard wildlife. If you live in a coastal area with a view of deep water or near a submarine canyon (like Monterey Bay), a high-resolution, long-range camera mounted on a stable tripod is essential. Use an AI-powered system that can distinguish between the rhythmic movement of waves and the sudden, sharp break of a dorsal fin. Because these dolphins often surface far from shore, a lens with at least 400mm to 600mm focal length is recommended.
For the best results, position your camera at a high elevation, such as a cliffside or high-rise balcony, looking down at a 15-to-30-degree angle. This angle reduces surface glare and helps the AI identify the distinctive white scarring and blunt head shape. Polarizing filters are non-negotiable; they cut through the ocean's reflection, allowing the camera to see the dolphin just beneath the surface before it breaches.
Set your camera to a fast shutter speed (at least 1/1000s) to freeze the action of a breach or splash. While baiting is not possible or legal for marine mammals, you can "lure" them into your frame by focusing on areas of high productivity, such as tidal rip lines or areas where sea birds are diving, as these indicate the presence of the cephalopods Risso's Dolphins crave. Early morning light or the "golden hour" before sunset provides the best contrast to highlight their white scars against the dark blue water.
Similar Species
Species that look similar or are commonly confused with Risso's Dolphin.
Frequently Asked Questions
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