A team of bioacoustics researchers from the University of Saint-Etienne in France discovered that Nile crocodiles respond to a variety of infant mammal noises, including human screams. The scientists investigated crocodile reactions to recordings of newborns screaming at CrocoParc in Agadir, Morocco, in their study, which was published in the journal Proceedings of the Royal Society B: Biological Sciences.
Previous research has revealed that crocodiles perk up and often head toward the sound of distress in prey, hoping for a quick and easy meal. The research team questioned if crocodiles would react similarly to other species that do not necessarily prey on this new endeavor.
They assembled a collection of recordings of babies of various species screaming or shrieking in distress to find out. The recordings included sounds from chimps, bonobos, and human infants in varying states of stress. Human recordings included wailing newborns receiving immunizations at home and in a medical office.
The team next traveled to Morocco’s CrocoParc, an outdoor facility designed to host over 300 crocodiles. The crocs are permitted to roam freely throughout the park and behave almost as if they were wild animals. The researchers set up speakers and played the audio while filming the crocodiles’ reactions.
The majority of the crocs responded to the audio, according to the study. They also noticed that when they heard extremely anxious cries, their replies became more immediate. They also discovered that most people reacted quickly, especially when the sounds indicated that a newborn of some type was in critical peril.
Notably, after approaching the speaker from which newborn cries were emanating, one croc, presumably a female, abruptly turned around and confronted others who had reacted. According to the experts, such a reaction is analogous to how a mother would react when safeguarding her children.
The research team concluded that baby screams are ubiquitous, and there is a lengthy history of crocodiles swallowing infants who venture too far from parental safety.