The BackScratcher Penguin has a very broad end to its beak. Like the Adelie penguin, the beak is almost completely covered with feathers, which allows heat to be conserved. The Backscratcher’s beak is extremely hard, but the feathers cushion the hardness, making it an ideal instrument to provide back massages to other species of penguin.
Backscratcher Penguins aren’t particularly good fishers; they can catch fish, but not with the same efficiency as other penguins. However, it’s believed these penguins obtain fish by providing a service to other penguins with sore backs or who feel stiff having stood on the ice for many hours on end.
Backscratcher Penguins live in colonies slightly away from other penguins. If one of these other penguins requires a massage, it will walk over to the Backscratcher Penguin colony and beat its own beak against those of the Backscratcher’s looking for a beak that feels right. Once a suitable Backscratcher has been found, the penguins will again touch each other’s beaks, but this time they will be negotiating a price, maybe half a fish for a smaller penguin or a whole fish for a particularly large Emperor Penguin.
Extract from Animals Evolution Forgot