Great White Shark just relaxing having a moment mouthing the strange object to learn more about it.
This video was taken at Seal Island in Mossel Bay a harbour town on the Garden Route in South Africa’s Western Cape Province. You can see other similar behaviour in some of the other clips on the channel.
As we can see in the video the camera starts above the water where you see a fairly limp body of a shark above the water with the head below. The shark is incredibly relaxed, it is not thrashing or expending any unnecessary energy and when the camera dips below the surface you can see that the sharks eyes are rolled forwards with its jaws (relatively) gently around the bars of the cage. The shark has found an intriguing object and without hands his primary tool of investigation is his mouth. When the shark loses interest it simply sinks down away from the cage releasing his jaws from the bars.
An interesting adaptation that has come in useful in this video is the constantly replacing teeth. Mouthing a steel cage or any hard objects is not great on teeth but when you need it to explore your surroundings they can often get damaged. As you see in the video when the shark backs off of the cage one of its teeth comes out. Sharks always have a new set of new teeth developing and they rotate forward like a conveyer belt, as the teeth are lost or worn down, replacements emerge. Sharks can go through thousands of teeth in their lifetime which allows them to continue to hunt effectively with damages and losses.