Grampus griseus
Silhouette: Chris huh · PhyloPic
In 3 days ~40% in a week ~60%
Risso's dolphin (Grampus griseus) is the only species of the genus Grampus in the family Delphinidae (dolphins). Some of the most closely related species to these dolphins include: pilot whales (Globicephala spp.), pygmy killer whales (Feresa attenuata), melon-headed whales (Peponocephala electra), and false killer whales (Pseudorca crassidens). These dolphins grow to be about 10 ft in length and can be identified by heavy scarring that appears white. They are located worldwide in cold to temperate waters, but most typically found along continental shelves due to their eating habits. Risso's dolphins have a diet that contains primarily cephalopods. They are able to search for prey at various depths due to their ability to reach depths of almost 600 m (2,000 ft). Individuals typically travel in pods ranging from 10 to 50 dolphins, with which they form tight social bonds.
Like most marine species, Risso's dolphins suffer from anthropogenic disruptions to the environment. Pollution, both from noise and plastics, is a common cause of higher mortality rates. Many can be, or have been, affected by entanglement in fishing nets and whaling. Risso's dolphins are currently protected in the United States, but they are still hunted in other parts of the world. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Channel Islands National Park | 🇺🇸 United States |
More parks will be added in future updates.
With luck
About 10% of wildlife watchers report a Risso's Dolphin sighting in Channel Islands National Park on a given day, based on 33 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 11th most-seen of the 22 mammals we can rate there. Over three days the chance rises to about 40%, and over a week to about 60%, if each day is a fresh chance.
January, March–April and November
In those months about 20% of wildlife watchers report a Risso's Dolphin in Channel Islands National Park on a given day, against under 5% in May, the lowest month. Those are among Channel Islands National Park's wettest months, with about 35 mm of rain a month against almost none in July.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Risso's Dolphin sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Only Channel Islands National Park, in our data
Channel Islands National Park is the only park on Wallace's Line with enough records to rate Risso's Dolphin sightings: about 10% of wildlife watchers there report one on a given day.
Same family: Delphinidae
The closest relatives of the Risso's Dolphin that you can see in Channel Islands National Park (family Delphinidae, Oceanic Dolphins) are Common Dolphin (about 30%), Bottlenose Dolphin (about 20%) and Killer Whale (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Risso's Dolphin is recorded against all the mammals logged in Channel Islands National Park (33 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
