Sharks are commonly represented by pop culture as predators that will almost certainly circle their prey before closing in for the kill. But the truth of the matter is that you wouldn’t see them coming if they were certain you were a food item – they probably aren’t all that convinced if they’re circling.

This, from HuffPo:

Sharks have less than stellar eyesight — they often rely on their ability to detect the electric fields of hidden prey — and are forced to take extra time to fully comprehend what they are seeing. To understand and study what they spy floating in the water — surfer, seal or otherwise — sharks circle to get a 360 degree picture, and more often than not they get it wrong.

But South African marine biologist, Alison Towner of Grootbos Private Nature Reserve says that Great Whites won’t circle in every scenario:

In Gansbaai White sharks are often observed circling objects to investigate – birds, items dropped over board, or decoys that may have occasionally been bitten off. The footage of Chris Fallows on a paddle board is a classic example of a shark checking something non prey out in good visibility and deciding not to bite. It seems that white shark hunting strategies are quite site specific and vary place to place. At Dyer Island we have tracked male sharks showing diurnal hunting patterns in the channel. One 4,2 metre male endlessly patrolled Shark Alley not far from the seal colony edge, stealthily using the kelp patches and then rushed up to predate on seals almost on the shore, very deliberate area restricted hunting patterns influenced by the visual senses of both predator and prey.

[Source : Huffington Post]