They have a bulbous head with a vertical crease and an indistinguishable rostrum. They have a tall, curved, sickle-shaped dorsal fin located mid-way down their back. Adult bodies are usually heavily scarred, with scratches caused from teeth raking between dolphins, as well as circular markings from prey (e.g., squid), cookie-cutter sharks, and lampreys.
Risso’s dolphins are found in the temperate and tropical zones of all the world’s oceans. These cetaceans generally prefer deeper offshore waters, especially near the continental shelf edge and slope, where they can dive to at least 1,000 feet and hold their breath for 30 minutes to catch their favorite prey: squid.
Diet
Squid
Population Status | Monterey
Least Concern
Legal Protection
Marine Mammal Protection Act, National Marine Protected Area Act
Threats
Biotoxin (Algal Blooms), Human Related Loss (Habitat Loss, Ocean Noise, Hunting, Food Source Loss, Climate Change, Disturbance, Entanglement, Harassment, Oil Spills, Pollution, Boat Strikes, Collisions)
Size
12ft (Female)
12’6″ft (Male)
Weight
1,000 lb (Female)
1,000 lb (Male)
BEHAVIORS
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Mating
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Spy Hop
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Breaching
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Kelping
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Tail-Lobbing
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Porpoising