A new study published in the journal Marine and Freshwater Research could become the basis for a new horror movie involving sharks: Scientists have reported that they have discovered 4 species of sharks evolving the ability to walk on land.
You heard that right, these sharks were caught in the act using their fins to walk like 4 legs. Although they still primarily live underwater, they are sometimes seen wading between coral reefs or even climbing entirely out of the water to move from one puddle to another.
Looking at these sharks, we can see Darwin’s theory of evolution is indeed at work.
The newly discovered sharks were found in a 12-year study, in collaboration with the University of Queensland, Australia, the Commonwealth Scientific and Industrial Research Organisation (CSIRO), the Florida Museum of Natural History, USA, and the Indonesian Institute of Science and Fisheries.
During this process, scientists confirmed a total of 9 species of walking sharks, including 4 newly discovered species off the northern coasts of Australia and New Guinea.
All these walking shark species belong to the genus Hemiscyllium, a group of sharks that diverged from the evolutionary tree during the Late Cretaceous period, about 66 to 100 million years ago. This means their appearance is quite different from their distant relatives like hammerhead or great white sharks.
In fact, all walking sharks look rather adorable. They have short snouts, high-set eyes, and distinctive spotted patterns that are very captivating.
“Measuring an average of less than 1 meter, walking sharks pose no threat to humans,” said biologist Christine Dudgeon from the University of Queensland. “But their ability to tolerate low-oxygen environments and their fin-walking capabilities give them a significant advantage when hunting small crustaceans and mollusks.”
Fortunately, these walking sharks are not a nightmare for us humans. But there remains a question to be answered: When did they become a nightmare for small crustaceans and mollusks?
Scientists say that the walking sharks of the genus Hemiscyllium have appeared in various vast marine areas throughout millions of years of history, making it difficult to determine when they learned to walk and why they developed this ability.
However, they can still make educated guesses. In this case, researchers suggest that the first Hemiscyllium learned to walk about two million years ago. This was a time when tectonic plates on Earth were still actively shifting, causing sea levels to change continuously along with the positions of coral reefs and small islands.
“Data suggests that the newly evolved walking shark species emerged after they left their original population, which became genetically isolated when moving to new areas and evolved into new species,” Dudgeon explained.
“They may have moved by swimming or walking on their fins, and hitchhiked across coral reefs drifting westward towards New Guinea about 2 million years ago.”
Additionally, Dudgeon’s research team predicts that the number of walking shark species will not be limited to 9. Somewhere on this Earth, there are still other shark species evolving to come ashore and walk. The question is whether we can find them or not.
Source: Sciencealert