It looks like something out of a storybook – and in fact it can be traced back to accounts told thousands of years ago – a crocodile opens its mouth, invites a bird in before … what? ::Chomp:: it swallows the sap alive? Amazingly, the crocodile remains still while the plover picks meat from its mouth. This cleans the crocodile’s teeth and prevents infection while providing a somewhat scary meal for the hungry bird.