Recordings Reveal Dolphin Mothers Employ a Unique Pitch to Communicate with their Calves

It’s easy to recognize when an individual is communicating with a toddler, and surprisingly, a similar phenomenon occurs among dolphin mothers – they modify their pitch to a form of “baby talk” when interacting with their young.

In a study unveiled on Monday, it was discovered that female bottlenose dolphins alter their vocal tones when addressing their offspring. The team of researchers were able to record the distinctive whistles of 19 mother dolphins located in Florida, both when they were with their calves and when they were swimming alone or alongside other adults.

This particular whistle is crucial for dolphins as it serves as their unique identifier – comparable to humans calling each other by names.

“They utilize these whistles to maintain contact. They’re essentially saying, ‘I’m present, I’m present’,” elaborated study co-author Laela Sayigh, a marine biologist at the Woods Hole Oceanographic Institution in Massachusetts.

When communicating with their offspring, the mother dolphins produced a higher pitched whistle with an increased pitch range than usual, the study, published in the journal Proceedings of the National Academy of Sciences, confirmed.

“This was consistently observed across all the 19 mother dolphins in the study,” added biologist Peter Tyack, a co-author of the study from the University of St. Andrews in Scotland.

The process of collecting this data was complex and time-consuming. For over thirty years, scientists repeatedly attached specialized microphones to the same wild dolphin mothers in Sarasota Bay, Florida, to document their distinctive whistles, both during the years when they had calves and when they didn’t. Dolphin calves usually stay with their mothers for about three years, and sometimes longer. Dolphin fathers, in contrast, don’t have a significant parental role.

Describing the research findings, Mauricio Cantor, a marine biologist at Oregon State University who did not contribute to the study, stated, “This is extraordinary, completely spectacular data. The study is a culmination of tremendous research efforts.”

The exact reasons why humans, dolphins, or other animals use “baby talk” remains unclear. Nonetheless, scientists theorize it could aid young ones in learning to articulate novel sounds. Previous studies suggest that infants may be more attentive to speech with a wider pitch range. Similarly, female rhesus monkeys might alter their calls to engage their offspring’s attention, while Zebra finches slow down and increase the pitch of their songs to address chicks, potentially simplifying birdsong learning.

However, for this dolphin study, the researchers only focused on the signature call, leaving it unclear whether dolphins use a similar form of baby talk for other types of communication or if it assists their young in learning to “speak.”

Frants Jensen, a behavioral ecologist at Denmark’s Aarhus University and a co-author of the study, expressed, “If similar adaptations exist in bottlenose dolphins, a long-lived, acoustically sophisticated species, where the young have to learn a vast array of sounds to communicate, it would make logical sense.”

Another potential explanation for employing specific pitches could be to gain the attention of the young dolphins.

“It’s crucial for a calf to differentiate when ‘Mom is specifically addressing me’ versus simply announcing her presence to others,” added Janet Mann, a marine biologist at Georgetown University, not part of the study.

You can follow Christina Larson on Twitter at: @larsonchristina

The Health and Science Department at The Big Big News is supported by the Science and Educational Media Group at the Howard Hughes Medical Institute. The content responsibility rests entirely with AP.

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