Look at these images and it's easy to imagine how a shark might mistake a swimmer or surfer for a seal.

At least that's the premise behind the "mistaken identity" theory that tries to explain why sharks sometimes attack people.

"You can see quite easily how that mistaken identity might come about," Dr Nathan Hart explains. Credit:Taronga Zoo

While the idea seems reasonable, even logical, it has never been tested until now.

At Taronga Zoo, researchers have this month run a series of experiments to understand what drives a shark to attack by mimicking what they see and hear underwater.