Did you know that there are female bullhead sharks that deposit their eggs at the same place – like a communal nesting site? Up to 15 eggs of the Japanese bullhead shark (Heterodontus japonicus) can be found in the same patch. Each egg has to rotate out of the mothers cloaca during several hours, as with all bullheads. The reason is the auger shape of the egg case – even if the egg of the Japanese bullhead shark is a little less elaborate. The eggs take about a year to hatch, and the newborns are 7.1 in -18 cm- long.
The Japanese bullhead shark is up to 3.9 ft -1.2 m- long and lives in the northwestern Pacific Ocean off the coasts of Japan, Korea and China at depths of 20 to 121 ft -6 to 37 m- over rocky bottoms or kelp beds. Just like all bullhead sharks, it has a pig-like snout, a ridge above each eye and fin spines. It has a characteristic pattern of irregularly shaped, vertical brown bands and stripes.
The Japanese bullhead shark can often be found in aquariums in Japan. It is harmless to humans and can even easily be hand-caught by divers. Considered as Least concern by the IUCN, it vanished from the gulf of Bohai in China, assumedly due to climate change. But, given that there is one of the busiest seaways in the world, there could be other reasons as well.