If you ever read the Brothers Grimm,  who popularised folk tales such as Cinderella, Hansel and Gretel, Rapunzel, Rumpelstiltskin, Snow White, you may also know the story of The Frog Prince.

There are various iterations of the tale, which sees a pampered, privileged princess coming across a prince who has been transformed into a frog. In some versions, the princess restores the frog to a prince by bestowing a kiss upon him.

These days, it seems, frogs and other amphibians could use more than a kiss. A number of frog populations are on the decline, and are recognised as endangered species.