Risso's dolphin
Grampus griseus
Risso's are among the most heavily scarred marine mammals — NOAA describes adults as usually covered in scratches from raking teeth and circular marks from squid, fading the skin from charcoal grey to near-white with age. Look for groups of 10–50 logging quietly at the surface off the Channel Islands, especially on calm October and November mornings.
About 1.8× as long as an average adult is tall.
A risso's dolphin runs about 10 ft. Drawn beside an average adult human — 5.7 ft standing, the CDC's own U.S. adult average.
Average adult human: 5.7 ft (5 ft 7 in), CDC NHANES U.S. adult average standing height.
Drawn to the same scale. 10 ÷ 5.7 ≈ 1.8.
At a glance
Length/weight/lifespan/diet: NOAA Fisheries species page →
What to look for
Best months to see
Last 30 days
This chart includes numerical reports only. Uncounted sightings do not appear in its totals; see the daily archive for presence reports.
Where to go (operators publish dated sighting reports)
We monitor public trip reports across Newport Beach, Long Beach, Dana Point and San Diego. Reporting schedules vary; summaries show the latest available report. Newport's shared feed is counted once.