African penguins have another name: “beach donkeys.” Early European explorers were said to have named them that after they followed the sound of donkey calls, only to find a coast full of birds. Now we know what these donkey calls mean.

African penguins aren’t the only penguins that sound like donkeys. Several species from South America do as well. African penguins, otherwise known as jackass penguins, are the most studied, and researchers have figured out what the donkey call means.

The penguins make a range of sounds from begging peeps to moaning contact calls—but they save the full donkey brays for when they want to attract a mate. These calls are what’s known as “ecstatic display songs,” and when a “donkey call” finally nets the penguin a mate, they sing together.

And if they like that, they should try listening to actual donkeys.

Image: Joachim Huber