Strolling with sharks

There is a small shark just under a metre long among the coral reefs of Papua New Guinea that does something quite incredible: it walks on land. It is called Hemiscyllium ocellatum (common name epaulette shark) and has very little of the typical shark appearance: long and tapered, it has a snout that makes it resemble a lizard, as well as two large round spots above its pectoral fins, which are large and robust. These fins allow the fish to move across the surface with the clumsy gait of a seal. What’s the shark doing out of the water? Hemiscyllium ocellatum catch crabs and other invertebrates in the warm pools that form between the reef corals. When prey is scarce, the fish come out of the water and take a few steps (up to 30 metres) to look for a more abundant pool. This trait is quite old; according to researchers, it evolved around 9 million years ago along with the ability to survive without breathing for as long as it takes to finish its walk.

In this video from Nature on PBS, we can see the shark moving among the surfaced corals: