Take a look at the teeth of any animal. The chances are you’ll then have a good idea if it’s a meat eater or a vegetarian. Sharp canines? Easy. All the better to eat you with. But how would you find out whether your chosen species got by on dead meat, or if it survived and thrived by catching live prey? To answer that kind of question you have to go beyond teeth and look at many other aspects of its biology—from the way the creature moves to how far it can see.