ZEBRA BULLHEAD SHARK

Taxonomy:

Phylum– Chordata

Class– Chondrichthyles

Subclass– Elasmobranchii

Infraclass– Euselachii

Superorder– Selachimorpha

Order– Heterodontiformes

Common Name– Bullhead Sharks

Family– Heterodontidae

Common Name– Bullhead Sharks

Genus– Heterodontus

Species– zebra

Status: IUCN Red List LEAST CONCERN

Average Size and Length: They are born around 15 cm. Immature males are at 44 cm/ 1.4 feet and mature at 64 cm/ 2.1 feet. The maximum recorded length is 122 cm/ 4 feet.

The egg cases ate about 12-18 cm/ 4.7-7 inches long.

Teeth and Jaw: The small front teeth are pointy and sharp for grabbing prey and side bottom teeth that are flat, perfect for cracking and grinding shells.

Head: They have a large blunt head, pig-like snout and a low supra-orbital crest gradually sloping behind eyes. There are two small spiracles behind the eyes.

Tail: The caudal fin has a moderately long dorsal lobe and moderately a long ventral lobe. The latter is shorter than the dorsal lobe. The vertebral axis is raised into the caudal-fin lobe.

Demographic, Distribution, Habitat, Environment and Range: The Zebra Bullhead shark can be found in the West Pacific in Japan, Korea, China, Taiwan Island, Indonesia, Vietnam and northwest Australia and Queensland. They can be found over continental and insular shelves from inshore down to at least 164 feet at the South China sea. Off of western Australia they can be found deeper between 492-656 feet. They prefer subtropical climates.

Diet: They more than likely feed on small invertebrates and fish.

Ram-Suction Index: Like the other members of its family, the Zebra Bullhead shark is more than likely high on the suction side of the index. They more than likely suck in prey and water from rocks and crevices and use their unique different teeth to pierce the prey with its sharp front teeth when the jaw extends, and crush and grind it with its molar like back teeth.

Aesthetic Identification: Like its name, the Zebra Bullhead shark has stripes like a zebra. They are white or cream with a drastic and striking zebra-striped pattern. The stripes are numerous ranging from black, dark-brown and even reddish-brown in juvenile sharks. There are vertical saddles and bands all over the body, head and tail. There are no spots. There are two dorsal fin spines and an anal fin present. They have large pectoral fins.

Biology and Reproduction: Their biology and reproduction are poorly known; however, they are oviparous. The shark embryos are protected within tough, auger or spiral-shaped eggs in which they lay. This shape enables them to be wedged into rock crevices, and kelp for protection from predators. The females wedge them in when they are soft, and after a few days the egg cases harden and are very difficult to move. When the egg cases are soft, they are lighter in color. When they harden, they become a much darker caramel brown color. There may be more than one female using same oviposition site, with as many eggs found in a single nest, however this isn’t confirmed.

It is suggested that females lay 2 eggs at a time, from spring to late summer in Japan, 6-12 times during a single spawning season. Eggs hatch within 1 year. Research suggests that during courtship, the male grasps the large pectoral fin of the female and wraps the posterior part of the body under her so a single clasper can be inserted into her cloaca. Research suggests that several mating sessions observed, copulation lasted as long as 15 minutes. However, this isn’t confirmed.

Behavioral Traits, Sensing and Intelligence: Their behavior is poorly known, but more than likely the Zebra Bullhead shark may have some similar behavioral traits as other members of their family. Which would be that they are nocturnal. They rest on cracks and crevices during the day, and are actively moving and hunting around their environment at night.

Speed: More than likely, they are poor swimmers, sluggish and slow moving just as the other members of their family are. The more than likely use their large pectoral fins to help it walk across the seabed and rocky surfaces and hold on to the rocks when hanging vertically. They probably have the ability to rest motionless on the bottom, while eating and breathing at the same time, like the other members of its family.

Zebra Bullhead Shark Future and Conservation: Currently, they are common and are of least concern. They are occasionally taken as bycatch.

Zebra Bullhead Shark Recorded Attacks on Humans: Harmless to humans (unless stressed), the Zebra Bullhead shark poses no threat. Their spines can impose a painful wound if not careful.