Port Jackson Shark

Port Jackson Shark (Heterodontus portusjacksoni)

You wouldn’t guess looking at them, but Port Jackson sharks are from a line of ancient sharks that are older than some dinosaurs! Though this species is generally quite peaceful and calm it is capable of delivering a painful bite if it feels threatened.

This species can live for around 30 years.

Port Jackson sharks are able to stay still whilst resting or sleeping whilst still being able to breathe. Some sharks are not able to do this, and must swim constantly even when sleeping. The difference is all to do with how they breathe. Sharks that have to move continuously breathe through ram ventilation, where the water is forced into the mouth and over the gills through the animals swimming in the water. Port Jackson sharks are able to breathe through buccal ventilation, where they alternate between opening and closing their mouths and gill coverings. This draws in water to their mouths even when the shark is staying still.

One of the key things that makes the Port Jackson shark stand out is that the females produce very unusual eggs; they are pretty big and in the shape of a corkscrew! As strange as it sounds, this shape actually helps keep the baby sharks inside safe. Once the female has laid the eggs, she is able to pick them up in her mouth, and wedge them into the cracks and crevices in between rocks. The corkscrew shape helps them to stay in and not fall out. Here, in the rocks, the eggs are much safer from any predators who would like to feast on them.