It’s Shark Week, and the Discovery Channel have already jumped the shark with a fake documentary, asking if a giant prehistoric shark Megalodon is actually still alive. It’s not, and the show was filled with lies, fabrications and actors playing scientists.

Here’s a radical alternative idea: I thought I might celebrate Shark Week by telling you some actual facts about sharks. This, therefore, is a collection of my earlier Not Exactly Rocket Science posts on sharks (and a couple of rays, for good measure).

On 25 August 2010, diver Gerardo del Villar, saw a great white shark off Guadalupe Island with two odd wounds on its head. One was a crescent-shaped scar. The other was a round crater, still open and bloody.