The cookie-cutter did it

It was one of the greatest mysteries of the deep blue sea. Migrating whales often turn up with crater-like wounds on their skin but, until now, nobody has ever known why or how the injuries are sustained. The main suspects ranged from barnacles to infection, but two South African scientists - Peter Best and Theoni Photopoulou, from the universities of Pretoria and Cape Town respectively - have finally solved this global mystery.