These sharks have evolved the ability to undulate their pectoral and pelvic fins in a way that allows them to "walk" across surfaces. Their musculature and skeletal system is different from most other sharks, allowing them to lift and move their body even without the help of buoyancy underwater. They can regulate their breathing and heart rate to survive in these low oxygen conditions.

You might be wondering why these sharks do this. When the tide lowers, there are small pockets of water that larger predators cannot access. During these periods, they have less competition when hunting and additionally don't have to worry about their own predators such as other sharks and groupers. Hunting prey also becomes easier when the prey has nowhere to go.