According to a study published Monday, female bottlenose dolphins change their tone when communicating with their babies. The researchers recorded the distinctive whistles (signature whistles) of 19 dolphin mothers in Florida when they were accompanied by their calves and when they swam alone or with other adults.
A dolphin’s signature whistle is a unique and important signal, equivalent to saying its name.
“They use those whistles to inform each other of their whereabouts. Periodically they say, ‘here I go, here I go,’ said study co-author Laela Sayigh, a marine biologist at the Woods Hole Oceanographic Institution in Massachusetts.
When signaling to their young, the mother’s whistle pitch is higher-pitched and the pitch range is greater than usual, according to the study published in the Proceedings of the National Academy of Sciences.
“This was true for all the mums in the study, all 19 of them,” said biologist Peter Tyack, a co-author of the study and from the University of St. Andrews in Scotland.
Obtaining these data was not easy. For more than three decades, scientists have repeatedly attached special microphones to the same wild mother dolphins in Florida’s Sarasota Bay to record their distinctive whistles. This spanned the years they had calves and the years they didn’t, as young dolphins stay with their mothers an average of three years in Sarasota; sometimes longer. Parents do not have a prolonged role in upbringing.
“This is unprecedented and absolutely fantastic information,” said Mauricio Cantor, a marine biologist at Oregon State University who was not involved in the study. “This study is the result of a great research effort.”
It’s not known for sure why people, dolphins and other creatures use different language when talking to babies, but scientists think it might help the baby learn to make new sounds. Research dating back to the 1980s suggests that human babies may pay more attention to a voice with a greater range of pitches. Female rhesus macaques alter their calls presumably to get and hold the attention of their young. And mandarin finches raise the pitch and slow down the rate of their calls when addressing their chicks, perhaps making it easier for the birds to learn to sing.
In the dolphin study, the researchers focused solely on their distinctive whistle, so they don’t know if the dolphins also use baby talk for other exchanges or if this helps the calves learn to “talk,” as seems to be the case. with humans.
“It would make sense that there would be similar adaptations in bottlenose dolphins, a long-lived and highly acoustic species,” whose young must learn to make lots of sounds to communicate, said Frants Jensen, a behavioral ecologist at Denmark’s Aarhus University and a co-author of the study.
Another possible reason to use specific tones is to attract the attention of the minor.
“It’s very important for a calf to know, ‘oh, my mom is talking to me now,’ versus just announcing her presence to someone else,” said Janet Mann, a marine biologist at Georgetown University, who was not involved in the study. .
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Christina Larson is on Twitter as @larsonchristina
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FUENTE: Associated Press
