The Port Jackson Shark is a nocturnal type of bullhead shark of the family Heterodontidae. Although listed as "Least Concern" on the World Conservation Union (IUCN) Red List, it is known that the shark's embryos experience very high mortality rates (89%). Its status is otherwise, largely unknown.
Port Jackson sharks are similar to other organisms in their genus, bearing a broad, flat head, an anal fin, and crests above its eyes. However, the species possesses characteristics that make them easily identifiable—their teeth and the harness-like markings which run for a majority of their body length. This feature runs from their eyes to their first dorsal fin and then across the rest of their body. Both of its dorsal fins are of close to equal size, each with a spine at the foremost edge. This is rumored to be of poisonous nature. Other features that help distinguish them are their small mouths and their nostrils, which are connected to their mouth.
The sharks have gray-brown bodies covered by black banding, which covers a large portion of their sides and back. One of these band winds over the face and progresses even to the shark's eyes. Another, harness shaped band goes around the back, continuing until the pectoral fins and sides. Thin dark stripes are also present on the back of Port Jackson sharks. These progress from the caudal fin to the first dorsal fin.
The teeth of the Port Jackson shark are arguably its most distinguishable feature. Unlike other sharks its teeth are different in the front and back. The frontal teeth are small, sharp and pointed, while the latter is flat and blunt. These teeth are helpful for these species towards it diet, which consists of mollusks and similar organisms; they are perfect for crushing. While they are young, the sharks have sharper teeth.
The shark's territory is habitually sited in stone settings on the bottom where it feeds. Though rocky environments are the most common sandy and muddy ones are also possibly, probably near seagrass. Since the shark is nocturnal, during the day it resides in low resistance areas such as caves.
Dietary items include sea urchins, molluscs, crustaceans, and fishes. Black sea urchins and Centrostephanus rodgersi are often eaten.