Deadly Reptiles Sing: Crocodiles and Alligators Communicate Similar to Birds

We all know that birds can sing, but did you know that alligators and crocodiles do the same? Scientists have discovered that these large reptiles will actually resonances to communicate with others.

When it comes to communication, animals push air past their vocal force, forcing the air trapped in the vocal tract to vibrate, or resonate. Yet no one knew if reptiles, such as crocodiles and alligators, used resonances to communicate with others.

"Adults of both sexes produce loud vocalizations known as bellows year round, with the highest rate during the mating season," said Stephan Reber, a zoologist who led the study, in an interview with The Daily Mail. "Although the specific function of these vocalizations remains unclear, they may advertise the caller's body size, because relative size differences strongly affect courtship and territorial behavior in crocodilians."

In order to learn a bit more about these reptiles, the researchers examined a small Chinese alligator. They turned her enclosure into a rudimentary sound box complete with heliox atmosphere. This is when the researchers noticed that her bellowing grunts sounded different in the heliox atmosphere.

So what does this mean? After months of analysis, the scientists found that the bellows sounded deeper in heliox and there were resonances that had shifted to higher frequencies. This revealed that crocodilians do use calls for communication.

"If bellows serve as advertisement calls, with formants (vocal tract resonances) as cues to size, crocodilians might be expected to extend their vocal tracts to maximum length during bellows," write the researchers. "The overall morphology of modern crocodilians is highly conserved across species, and all species produce bellow-like vocalizations, suggesting that all crocodilians may possess formants."

The findings are published in the Journal of Experimental Biology.

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