Cartilaginous fish · Heterodontiformes · Heterodontidae

Horn Shark

Heterodontus francisci

Least Concern

The species is abundant and widely distributed; it faces no significant short-term risk. See full glossary

The horn shark is a small bottom-dwelling shark with two defensive spines in front of the dorsal fins and a heavy, pig-like head. It eats sea urchins and molluscs, which it crushes with flattened rear teeth. Its egg is one of the strangest objects in the sea: a spiral-shaped capsule that the female wedges among the rocks.

Weight

5 kg – 10 kg

Size

70 cm – 1.2 m

Lifespan

25 years

Diet

Carnivore

Feeds mainly on other animals.

Activity

Nocturnal

Active mainly at night.

Social structure

Solitary

Lives and hunts alone, joining others only to breed.

Sighting difficulty

Easy

OceanCarnivore Nocturnal Solitary Fish Ocean

2countries 6parks 11dive sites

Fun facts

Its egg is a spiral: a horny capsule with two helical flanges that the female literally screws into a crack in the rock by turning it with her mouth, so that the current cannot carry it away.
The sea urchins it eats stain its teeth and spines purple, a detail that reveals what a particular individual has been feeding on.
It is extremely slow to reproduce: it lays only two eggs every two weeks during the season and incubation lasts nine months, one of the longest developments of any egg-laying shark.

Life cycle & biology

Skeleton type: Vertebrate - cartilaginous skeleton (fish)
Habitat & environment: Rocky bottoms, kelp forests and reefs of the eastern Pacific, from California to Mexico
Sexual maturity: 10 years
Gestation / incubation: 9 months of egg incubation
Litter / clutch size: 2 eggs

Sources consulted: https://es.wikipedia.org/wiki/Heterodontus_francisci