A blunt-headed bottom shark with a dark harness marking, resting under ledges by day in the temperate south-east.
To about 1.65 m, pale grey-brown with a dark harness marking running from behind each eye, across the back and down the flanks. The head is blunt and high with a pig-like snout, and there is a spine at the front of each dorsal fin, which is what a heterodontid is. The teeth are the other character and are the reason for the family name: pointed at the front for gripping, flattened at the back for crushing shellfish.
It spends the day resting under ledges and in caves, often several together and often on top of one another, and feeds at night on urchins, molluscs and crabs. The egg case is the thing most divers remember: a dark spiral, screwed like an auger, which the female wedges into a rock crevice where the water cannot lift it out. Empty cases wash up in numbers on southern beaches. It is a winter animal on the New South Wales coast, aggregating to breed and then dispersing.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.