Crocodiles are drawn to the sounds of crying babies, new research suggests.

Nile crocodiles were found to react to the cries of baby bonobos, chimpanzees, and humans – and they appear to be able to detect the degree of distress, research published in Proceedings of the Royal Society B, the Royal Society’s main biological research journal, found.

Researchers played audio recordings of infants crying to the carnivorous crocodiles and discovered they were drawn to those in the most distress.

The reactions could be explained as predatory by the giant reptiles, but it may also suggest a maternal instinct in female crocodiles, the researchers said.

Around 300 Nile crocodiles at CrocoParc in Agadir, Morocco, were played the sounds of cries on loudspeakers, per The Independent, with many of the crocodiles responding quickly.

The higher the infant’s distress level, the more crocodiles would respond.


“Our experiments obviously do not mean that crocodiles cannot be attracted by other signals than distress calls – they are opportunistic hunters,” the authors wrote in the study, “but they suggest that the readiness of these animals to react increases with the presence of acoustic features marking a level of distress.”

“It cannot be entirely ruled out that some individuals responded in a parental care context,” they said.

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The researchers compared the findings to another study in which a group of humans were played the same cries. It revealed that humans and crocodiles use different criteria to judge distress in other species and that humans’ judgment is less accurate.

While humans primarily responded to the pitch of the cries, crocodiles responded based on levels of “deterministic chaos, harmonicity, and spectral prominences.”

A crocodile in a tank at the Dubai Crocodile Park in the United Arab Emirates. Photo: EPA-EFE

The authors noted that crocodiles could recognise the distress levels of species very distantly related to them.

Nile crocodiles can grow to about 20 feet long and can weigh up to 1,650 pounds, per National Geographic.


The creatures “live throughout sub-Saharan Africa, the Nile Basin, and Madagascar in rivers, freshwater marshes, and mangrove swamps,” it adds.

According to the publication, Nile crocodiles generally live close to humans, meaning encounters happen relatively often. It estimates that up to 200 people a year die from Nile crocodile attacks.