Japanese Bullhead Shark

Fascinating facts about the Japanese Bullhead Shark

• It lives at depths of 6–37 m (20–121 ft) over rocky reefs on the continental shelf.
• It measures up to 1.2 m (3.9 ft) long and has 11–14 dark vertical bands and stripes.
• When it hunts, the shark “walks” along the bottom using alternating pectoral and pelvic fins, then snaps its highly protrusible jaws shut to crush shells with molar-like back teeth. This quirky locomotion and bite mechanics reveal a predator built for cracking hard prey, not chasing fast fish.
• Females lay spiral-flanged egg capsules at 8–9 m (26–30 ft) depth, and up to 15 eggs can gather in a communal nest where several females spawn together, yet they abandon the site afterward. The communal nesting strategy shows a rare blend of cooperation and independence among sharks.
• In Japanese waters, a female can lay eggs 6–12 times from March through September, with the peak spawning in March and April, and each egg takes about a year to hatch into an 18 cm (7.1 in) newborn. This long developmental period highlights how slow-growing sharks depend on stable habitats for successful reproduction.

At a glance

About the Japanese Bullhead Shark

The Japanese bullhead shark, Heterodontus japonicus, glides over the rocky shelves of the northwestern Pacific like a living relic, its short, blunt head and pig-like snout framing a mosaic of irregular brown bands and stripes that ripple from snout to tail. Growing to a modest 1.2 m, it bears two high dorsal fins crowned with stout spines, a broad anal fin set well forward of a caudal fin that ends in a pronounced ventral notch. Its eyes, lacking a protective nictitating membrane, sit above tiny spiracles, while a pair of flaps of skin guide water into nostrils that split into incurrent and excurrent openings. Beneath the small mouth, sharp front teeth with central cusps and lateral cusplets give way to molar-like back teeth, perfect for crushing the crustaceans, molluscs, small fishes and sea urchins that make up its diet. When hunting, it “walks” along the seabed, alternating its pectoral and pelvic fins, then snaps its protrusible jaws shut, grinding prey into bite-size pieces.

More fish to discover

Browse Feravox