You know instantly when someone is speaking to an infant or small child. It turns out that dolphin mothers also use a kind of high-pitched baby talk.

found that female bottlenose dolphins change their tone when addressing their calves. Researchers recorded the signature whistles of 19 mother dolphins in Florida, when accompanied by their young offspring and when swimming alone or with other adults.

The is a unique and important signal 害羞草研究所� akin to calling out their own name.

害羞草研究所淭hey use these whistles to keep track of each other. They害羞草研究所檙e periodically saying, 害羞草研究所業害羞草研究所檓 here, I害羞草研究所檓 here害羞草研究所�,害羞草研究所� said study co-author Laela Sayigh, a Woods Hole Oceanographic Institution marine biologist in Massachusetts.

When directing the signal to their calves, the mother害羞草研究所檚 whistle pitch is higher and her pitch range is greater than usual, according to the study published in the journal,

害羞草研究所淭hat was true for every one of the moms in the study, all 19 of them,害羞草研究所� said biologist Peter Tyack, a study co-author from the University of St. Andrews in Scotland.

Obtaining this data was no simple feat. Over more than three decades, scientists placed special microphones multiple times on the same wild dolphin mothers in Florida害羞草研究所檚 Sarasota Bay to record their signature whistles. That included years when they had calves and when they didn害羞草研究所檛 害羞草研究所� dolphin calves stay with their mothers for an average of three years in Sarasota, and sometimes longer. Fathers don害羞草研究所檛 play a prolonged role in parenting.

害羞草研究所淭his is unprecedented, absolutely fantastic data,害羞草研究所� said Mauricio Cantor, an Oregon State University marine biologist who was not involved in the study. 害羞草研究所淭his study is the result of so much research effort.害羞草研究所�

Why people, dolphins or other creatures use baby talk isn害羞草研究所檛 certain, but scientists believe it may help offspring learn to pronounce novel sounds. Research dating back to the 1980s suggests that human infants may to speech with a greater pitch range. may alter their calls to attract and hold offspring害羞草研究所檚 attention. And Zebra finches and slow down their songs to address chicks, perhaps making it easier to learn birdsong.

For the dolphin study, the researchers focused solely on the signature call, so they don害羞草研究所檛 know if dolphins also use baby talk for other exchanges 害羞草研究所� or whether it helps their offspring learn to 害羞草研究所渢alk害羞草研究所� as it seems to do with humans.

害羞草研究所淚t would make sense if there are similar adaptations in bottlenose dolphins 害羞草研究所� a long lived, highly acoustic species,害羞草研究所� where calves must learn to vocalize many sounds to communicate, said Frants Jensen, a behavioral ecologist at Denmark害羞草研究所檚 Aarhus University and a study co-author.

Another possible reason for using specific pitches is to catch the kids害羞草研究所� attention.

害羞草研究所淚t害羞草研究所檚 really important for a calf to know 害羞草研究所極h, Mom is talking to me now害羞草研究所� __ versus just announcing her presence to someone else,害羞草研究所� added Janet Mann, a marine biologist at Georgetown University, who was not involved in the study.

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Follow Christina Larson on Twitter at: @larsonchristina

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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute害羞草研究所檚 Science and Educational Media Group. The AP is solely responsible for all content.

Christina Larson, The Associated Press

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