A team of academics from Florida Atlantic University and Australia’s James Cook University is studying epaulette sharks, a rare kind of shark. Using their paddle-shaped fins, young individuals of this species have learnt to walk on land. They can also survive for two hours without oxygen and hunt for prey in reef areas where most other sharks would never venture.
Because epaulette sharks are believed to prey only on aquatic animals such as small fish and not on land animals, they spend much of their time walking in and around the reef. During the trial, however, the researchers observed that the sharks could move up to 30 meters on dry land using their fins. The odd skills of epaulette sharks are being seen as an evolutionary step toward weathering the ongoing climatic crisis.
According to the study’s authors, “such locomotor features may not only be critical to survival but also to their prolonged physiological function under demanding environmental conditions, especially those linked with climate change.”
Is there any other walking sharks?
Hemiscyllium ocellatum is the scientific name for the epaulette shark researched by the researchers. Surprisingly, they are not the only shark species capable of walking. According to a 2020 study, at least nine shark species have gained the ability to live on land using their fins.
They are all members of the genus Hemiscyllium, and most are restricted to reefs in the Malay Archipelago. However, Hemiscyllium ocellatum is the first Papuan epaulette shark species (sharks found off the coast of Papua New Guinea) to be discovered to walk.
It also plays an important function in their survival. When a predator pursues epaulette sharks, they can walk into small reef cracks with the help of their fins, or they can pull themselves to dryland if necessary. Furthermore, their ability to walk permits them to feed in areas with less competition.
These walking sharks are rapidly changing in order to adapt to climate change.
During their research, the researchers discovered that epaulette sharks are more adapted to climate change than many other aquatic species. Their ability to exist in the absence of oxygen makes them well-suited to dealing with higher CO2 concentrations and tolerating circumstances such as hypoxia (oxygen deprivation in blood and bodily tissues) that may emerge as a result of climate change.
The evolution of epaulette sharks is likewise quite rapid. For example, it only took them roughly nine million years to acquire fins that allowed them to walk. The thresher shark, a rare long-tail shark, had to wait 55 million years to evolve. Furthermore, despite having less genetic diversity in their population, they are producing new species at breakneck pace.