How do penguins differentiate?

Emperor penguins don't build nests but bring eggs on their feet. They identify each other with a special two-voice cry instead of relying on sight.

Imagine you are a child returning to the territory after swimming. You need to find your partner and your children, but how? Emperor penguins don't make nests, so there's no fixed place for you to go and hope to meet your family. Only a large group of penguins stood around on an iceberg. It was very loud, and worse, all penguins looked quite similar. So how do you distinguish who?

Penguins recognize each other with a cry.

Emperor penguins have a cry of two special voices that can be used to identify individuals. This system takes advantage of the characteristics of the bird's body: the bird's phonetic organ, which controls and separates it into a fork in the trachea. This allows many birds to create two separate voices at the same time.

Emperor penguins use two branches of esophagus to produce two different frequencies at the same time, creating a characteristic rhythm of the rhythm. Scientists have determined that these characteristics carry enough personal information for penguins to recognize each other.

The characteristic of this rhythm can also be realized more easily than the sound of a voice in the surrounding noise of a penguin territory, and it moves through obstacles more easily (mostly crowded bird clusters) . Previous experiments showed that when emperor penguins could not make sounds, they had difficulty recognizing each other because they were only based on sight.

King penguins also identify each other with a two-voice cry.

This identification system is also seen in the king's penguin. Like emperor penguins, king penguins also carry eggs on their feet instead of building nests. The species of penguins build their nest does not seem to use a two-tone cry, because they can find each other by returning to their nest.