Crocodiles are drawn to the wails of crying human babies and infant primates
A new study has revealed that Nile Crocodiles respond to the cries of infants in addition to the infant chimpanzees’ cries and bonobos.
Furthermore, Crocodiles were found to be more at ease with higher-intensity cries. They may be more adept at picking up the degree of distress expressed in these cries than humans.
The study doesn’t reveal whether the behavior was triggered by crocodiles’ desire to hunt vulnerable prey or for a different motive, like confusing infants’ cries as the juvenile crocodiles’ cries, such as the ones that could be sounded like screaming or cooking. These findings give scientists greater insight into how reptiles see the world around them.
Researchers played the cries of bonobos, chimpanzees, and human babies to a group of Nile Crocodiles ( Crocodylus niloticus) in a zoo, recording the number of Crocodiles that turned their heads or moved toward speakers in reaction to the sound. The results were published on 8 August. 8. in Proceedings of the Royal Society B.
The crocodiles reacted to the cries of bonobo, human, and chimp babies. The sound of each cry was not similar.
The researchers used audio recordings of human infants from two situations: bath time at home alongside their families, resulting in a lower intensity of crying, and during vaccinations in the doctor’s office which resulted in a more intense outcry.
Sure, the most violent baby cries led to an increased percentage of crocodiles responding. To determine if specific characteristics of these sounds caused the crocodiles to get excited, they also examined specific acoustic factors of the cries they studied.
They discovered that the Crocs were more sensitive to crying sounds, with more incredible energy in higher frequency, and also crying sounds with certain irregularities in the sound patterns of the waves. Both are related to higher anxiety levels, as the authors pointed out.
Imagine a baby crying that is upset. The sound is different everywhere as the baby screams and loses breath. Miriam Boucher, a doctoral student at Clemson University, was not involved in the latest research, she told Live Science.
Humans are prone to classify higher-pitched calls as more distressing. However, the authors pointed out this only sometimes results in a correct evaluation. For instance, according to the study authors, since bonobo cries tend to be higher pitched than human cries, People tend to underestimate the level of distress that bonobo cries are. On the contrary, crocodiles do not seem to react differently to calls of various pitches.
” Crocodiles thus seem particularly adapted at estimating the degree of distress encoded in an infant’s cry regardless of the hominid species considered,” the authors observed.
It’s possible that the animals heard distress signals to identify a likely meal nearby. The researchers noticed that some Crocodiles responded by swimming in the water. It could be a prey-type move. Boucher said that the ability to swim underwater could indicate they were careful when examining the sounds.
The crocodiles may respond to these calls for a motive other than predation. The study didn’t examine the crocodiles’ responses to these calls to different sounds, like the distress call of a crocodile in its juvenile stage or an unison sound. Kent Vliet, a former biologist working at the University of Florida who was not part of the new study, told Live Science that he’s seen the crocodilians (a species that includes crocodiles as well as caimans and alligators) react strongly to calls for help from young animals even when they were from different species of crocodilian.
Additionally, the animals could be interested in hearing the sound of a different animal nearby.
“What I’ve seen in my own work,” Boucher declared, “is crocodilians can be pretty curious about things in general.”