Cephaloscyllium ventriosum
Silhouette: Birgit Lang · PhyloPic
In 3 days ~50% in a week ~80%
The swell shark (Cephaloscyllium ventriosum) is a catshark in the family Scyliorhinidae. It is found in the tropical and subtropical eastern Pacific Ocean from between central California to southern Mexico, with an additional population off the coast of Chile. They are known to have brown and white spots along with broad heads. As a defense, the swell shark is able to expand to approximately double its regular size by swallowing water. They depend on electrical signals to find prey, camouflaging in rocky crevices.
When discovered in 1880, the swell shark was first described as Scyllium ventriosum, but was later changed to Cephaloscyllium ventriosum. The genus name comes from the Greek word kephale, which means "head", and skylla, which means a certain kind of shark. The species name comes from the Latin word ventrĭōsus, which means "large-bellied". The species name refers to its ability to enlarge itself by taking in water.
The swell shark is found in the eastern Pacific Ocean, from the central California coast to southern Mexico. There is an additional population off the coast of Chile. It can be found between the depths of 5 and 457 m... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Channel Islands National Park | 🇺🇸 United States |
More parks will be added in future updates.
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | SeaWorld Orlando | 🇺🇸 United States | |
| 2 | Riverbanks Zoo | 🇺🇸 United States | |
| 3 | Discovery Cove | 🇺🇸 United States | |
| 4 | L'Oceanogràfic | 🇪🇸 Spain | |
| 5 | The Living Planet Aquarium | 🇺🇸 United States | |
| 6 | Georgia Aquarium | 🇺🇸 United States | |
| 7 | Monterey Bay Aquarium | 🇺🇸 United States | |
| 8 | Newport Aquarium | 🇺🇸 United States | |
| 9 | Oklahoma Aquarium | 🇺🇸 United States | |
| 10 | Ripley's Aquarium of Canada | 🇨🇦 Canada | |
| 11 | Ripley's Aquarium of the Smokies | 🇺🇸 United States | |
| 12 | Ripley's Aquarium of Myrtle Beach | 🇺🇸 United States | |
| 13 | Birch Aquarium | 🇺🇸 United States | |
| 14 | Cabrillo Marine Aquarium | 🇺🇸 United States | |
| 15 | Tennessee Aquarium | 🇺🇸 United States | |
| 16 | Aquarium of Niagara | 🇺🇸 United States | |
| 17 | REEF/Aquarium | 🇺🇸 United States | |
| 18 | Seaside Aquarium | 🇺🇸 United States | |
| 19 | Heal the Bay Aquarium | 🇺🇸 United States | |
| 20 | Ty Warner Sea Center | 🇺🇸 United States |
Possible
About 20% of wildlife watchers report a Swellshark sighting in Channel Islands National Park on a given day, based on 7 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 7th most-seen of the 7 sharks and rays we can rate there. Over three days the chance rises to about 50%, and over a week to about 80%, if each day is a fresh chance.
November
In that month about 70% of wildlife watchers report a Swellshark in Channel Islands National Park on a given day, against under 5% in April and June–July, the lowest months. December to February have too few records to rate.
Between 2 and 5 pm
Across all the parks we cover, that three-hour window holds the most Swellshark 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 Swellshark sightings: about 20% of wildlife watchers there report one on a given day.
GBIF citizen-science records
It is estimated from how often the Swellshark is recorded against all the sharks and rays logged in Channel Islands National Park (7 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.
