News: Scientists recently discovered four new species of sharks that use their fins as feet to walk along the sea bed in the waters around Northern Australia and Papua New Guinea.
What? One imagines sharks swimming in the depths of the ocean looking for prey but there are groups of sharks that use their fins to move over rocks and sand on the sea bed and even coral at low tide.
How do they look? They are less than a metre long (3 feet) and have military-like patterns on them. They prey on small crustaceans such as crab and shrimp and mollusks in shallow waters. They are very resilient to warm water and can withstand low oxygen environments.
Why is this discovery important? This isn’t the first time scientists have discovered walking sharks. During this 12 year-long study, scientists were sampling DNA of the only known walking shark species to estimate when they evolved. They found four new species while they were at it bringing the total number of known walking shark species to 9.
To give this discovery some context it is important to know that, sharks are very old creatures. Some form of this fish has existed on our planet for 450 million years (older than dinosaurs). In addition, they are very slow to evolve, slow to reproduce, and long-lived.
But the study of their DNA reveals that walking sharks only evolved their unique capability 9 million years ago making them the ‘youngest’ sharks on our planet. Of the 4 new species that diverged (changed) from the other walking sharks, the youngest species may have evolved less than 2 million years ago.
This is exciting for scientists as this may be the one place in the world where they can study the evolutionary process by which walking sharks evolve to become distinct species.