The reported discovery of a giant crocodile's head on a South African beach has locals fearing a huge great white shark is on the prowl.



Brigitte Cary-Smith and husband Neale, from St Lucia, discovered and filmed the crocodile head while walking their dogs down a beach near their home.



The video has attracted worldwide attention, with coverage on CNN and The Daily Mail, among many others.



In the video, Neale can be heard describing the reasons why they think a giant shark is responsible.



"You can see where the shark has actually ripped it... on the side here in the flesh you can see the shark teeth.''



At one point he asks Brigitte to put her hand on its head and then he tries to pry its jaws open. He theorises that the crocodile, likely more than 3 metres long, has probably gone out a nearby river mouth and then been chomped.



"It's quite normal for sharks to swim here in the sea at St Lucia and it's also very normal for very large sharks to be very close to the shore."



Other possibilities mooted include poachers, but the Daily Mail reported this was unlikely as the head and jaw were normally the most valuable part of the animal.