Burping, barking and begging: study reveals how whale calves communicate with mothers
Published in Science & Technology News
As many parents can attest, babies often make telltale noises when they’re hungry. It turns out, newborn whales do the same thing.
Humpback whale calves signal their desire to eat by making barking, burping, begging and snorting sounds, according to a study published on Dec. 18 in the journal Proceedings of the Royal Society B: Biological Sciences.
While whale vocalizations are not new to science, these specific cacophonies of cues had previously gone unidentified due to the logistical difficulties of studying the aquatic creatures, particularly while they are nursing.
“This is a nice start, at least from my perspective, in understanding what whales ‘say’ to each other,” Dr. Maevatiana Ratsimbazafindranahaka, the lead study author, told McClatchy News in an email.
In order to reach their conclusions, researchers attached multi-sensor tags equipped with cameras to whale calves. These tools were fastened to the animals using a cautious, gentle approach in order to minimize any disturbances.
Once the data was collected, the calls were then categorized using clustering techniques.
The researchers found that suckling sessions — periods when calves drank milk from their mothers — were associated with low-frequency calls that sound like burping, snorting and barking.
“The surprising and funny part is that we always had these barking and burping calls right in front of our eyes (ears?) when we were listening to various recordings from calves,” Ratsimbazafindranahaka said.
“But only when we finally managed to accurately describe nursing behavior did we realize they were, in fact, linked to nursing,” Ratsimbazafindranahaka added. “And it seems like calves mainly rely on these sounds to nurse.”
Audio recordings also indicated that, during feeding sessions, the calves made begging sounds — a phenomenon observed in many other species, but never in humpback whales.
“Begging behaviors are common and well-described in terrestrial mammals,” Ratsimbazafindranahaka said. “After all, the survival and success of the young rely on their ability to get enough food in the form of milk from their mother.”
Other sounds were also documented and associated with different types of behavior.
For example, while playing at the ocean surface, calves elicited mid-frequency calls, which sound like whooping noises.
One of the main takeaways from the study is the realization that man-made noises in the ocean could have an effect on the ability of whale calves to communicate.
“These pairs seem to use low-frequency calls, which can easily be masked by boat motors, for example, to initiate one of their most vital activities,” Ratsimbazafindranahaka said.
The study was carried out with the assistance of Paris-Saclay University, the University of Antananarivo in Madagascar and the Cétamada Association.
In addition to Ratsimbazafindranahaka, the study authors are: Chloé Huetz, Anjara Saloma, Aristide Andrianarimisa, Olivier Adam and Isabelle Charrier.
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