Sharks are considered as one of the fascinating animals roaming in the ocean. There are numerous types of sharks that are sailing in the world’s oceans for hundreds of millions of years. Recently, scientists have discovered four new species of sharks that can walk. Don’t worry; they are not the scary ones. Walking sharks are such revolutionary superstars that have recently evolved on Earth and belong to the genus Hemiscyllium.
Shark scientists published their findings this week in Marine and Freshwater Research. The researchers spent almost 12 years to study the samples of DNA collected from that first species, discovering four new ones in the process. These species live in tropical waters between northern Australia and New Guinea. They are three-foot-long in size.
"The discovery proves that modern sharks have remarkable evolutionary staying power and the ability to adapt to environmental changes," said Mark Erdmann, the paper's co-author and Conservation International Vice President of Asia-Pacific marine programs. These tiny sharks walk along the seafloor in search of food by using its fins. They move their pectoral fins in the front and pelvic fins in the back to clump. They can walk along the seafloor, outside water, atop coral rocks, at low tide.
“During low tides, they became the top predator on the reef,” says Christine Dudgeon, a researcher at the University of Queensland in Brisbane, Australia.
"We estimated the connection between the species based on comparisons between their mitochondrial DNA which is passed down through the maternal lineage," Dudgeon says.
"This DNA codes for the mitochondria, which are the parts of cells that transform oxygen and nutrients from food into energy for cells," he continued.
Depending on the differences in the sharks, scientists found that the walking sharks started to get separated from their evolutionary relatives around 9 million years ago. Sharks are older than dinosaurs, dominating the sea for 400 million years. The changing behaviour of these sharks may have occurred due to changing sea levels and shifting landscapes that influenced other nine known species to get settled eastern Indonesia and neighbouring islands, New Guinea and parts of Australia.
Like other sharks, they also have life risks because of over-fishing and harvesting for the aquarium trade. Dudgeon also explains that these animals are “homebodies,” laying eggs in the reefs and don’t move far from their birthplace. The research team predicts there may be more walking shark species present in the oceans that are yet to be discovered.