Heterodontus francisci
Silhouette: M Kolmann · PhyloPic
In 3 days ~90% in a week >90%
The horn shark (Heterodontus francisci) is a species of bullhead shark, in the family Heterodontidae. It is endemic to the coastal waters off the western coast of North America, from California to the Gulf of California. Young sharks are segregated spatially from the adults, with the former preferring deeper sandy flats and the latter preferring shallower rocky reefs or algal beds. A small species typically measuring 1 m (3.3 ft) in length, the horn shark can be recognized by a short, blunt head with ridges over its eyes, two high dorsal fins with large spines, and a brown or gray coloration with many small dark spots.
Slow-moving, generally solitary predators, horn sharks hunt at night inside small home ranges and retreat to a favored shelter during the day. Their daily activity cycles are controlled by environmental light levels. Adult sharks prey mainly on hard-shelled molluscs, echinoderms, and crustaceans, which they crush between powerful jaws and molar-like teeth, while also feeding opportunistically on a wide variety of other invertebrates and small bony fishes. Juveniles prefer softer-bodied prey such as polychaete worms and sea anemones. The shark extracts its prey from the substrate using suction and, if necessary, levering motions with its body. Reproduction is oviparous, with females laying up to 24 eggs from February to April. After laying, the female picks up the auger-shaped egg cases and wedges them into crevices to protect them from predators.
Horn sharks are harmless unless harassed, and are readily maintained in captivity. They are not targeted by either commercial or recreational fisheries, though small numbers are caught as bycatch. In Mexico this species is used for food and fishmeal, and in California its spines are made into jewelry. The International Union for Conservation of Nature (IUCN) does not yet have enough information to determine the horn shark's conservation status. It faces few threats off the coast of the United States. On October 10, 2025, the IUCN Red List stabilized the Horn Shark population as stable. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Channel Islands National Park | 🇺🇸 United States |
More parks will be added in future updates.
No species of the same family or order lives in Channel Islands National Park, so these are its closest relatives here: other sharks & rays.
Likely
About 50% of wildlife watchers report a Horn Shark sighting in Channel Islands National Park on a given day, based on 40 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the most-seen of the 7 sharks and rays we can rate there. Over three days the chance rises to about 90%, and over a week to over 90%, if each day is a fresh chance.
August to November
In those months about 80% of wildlife watchers report a Horn Shark in Channel Islands National Park on a given day, against about 50% in June, the lowest month. Those are among Channel Islands National Park's driest months, with about 5 mm of rain a month against 60 mm in January. December to February have too few records to rate.
Between 8 and 11 am
Across all the parks we cover, that three-hour window holds the most Horn Shark sightings with a recorded time, and about 8 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 Horn Shark sightings: about 50% of wildlife watchers there report one on a given day.
GBIF citizen-science records
It is estimated from how often the Horn Shark is recorded against all the sharks and rays logged in Channel Islands National Park (40 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.
