Isn't it heartwarming to recognise in animals a romantic behaviour typical of humans? While elephants use their trunks instead of hands to caress one another, penguins give stones in place of flowers and candy when courting the ladies. Hold on, people actually do the same with precious stones, and while a man might search for the finest diamond, male penguin will go looking for the smoothest pebble he can find. Having selected one, he'll offer it to the girl he fancies, and she will show her acceptance (of both the pebble and the guy) by putting it in her nest. They try to be monogamous and some breeds will mate with the same partner each year. However, if their sweetheart fails to show up, they'll choose another.