Dr. Riley Elliott returns to Australia's Norfolk Island with underwater cinematographer Kina Scollay to see what happens when the island's tiger sharks go head-to-head with migrating great whites over an unusual food source: cow carcasses.

Shark experts Dr. Riley Elliot and Kori Burkhardt conduct a one-of-a-kind shark competition to determine which male great white is the alpha in the pack. To see who has the most swagger, they test the sharks' speed, hunting ability and fearlessness.

Shark scientist Riley Elliot is on Norfolk Island to discover if the practice of tossing animal carcasses in the sea has changed the behaviour of the area's huge tiger sharks.

Great white male and female sharks battle each other in a series of contests to prove which is the superior sex.