Baby talk is used by mothers of bottlenose dolphins to communicate with their young.

• Rating

• language
• inflections
• child-directed communication
• higher pitches
• pitch range
• dolphin communication
• marine animal behavioral ecologist

Humans often use a squeaky, high-pitched speech pattern known as "baby talk" while communicating with small children. It was discovered that certain species of dolphins have this trait.

According to a study that was published on June 26 in the Proceedings of the National Academy of Sciences, bottlenose dolphin mothers alter their own uniquely identifiable whistles when their young are in the immediate vicinity. This "parentese" might potentially improve a calf's attention, bonding, and verbal learning, similar to how it seems to do in humans.

Each common bottlenose dolphin (Tursiops truncatus), during its first few months of life, develops a distinctive song, often known as a trademark whistle, which is similar to a name (SN: 7/22/13). Laela Sayigh, a marine researcher at the Woods Hole Oceanographic Institution in Massachusetts, believes that the dolphins call out their own "names" in the water "probably as a way to keep track of each other."

However, it seems that mother dolphins change their tune when their young are around. Dolphin calves usually stay close to their mothers for the first three to six years of their lives. Sayigh initially became aware of this shift after reading about it in a research conducted by one of her students and published in 2009. But, as she puts it, "it was just one little piece of this much larger study,"

Sayigh explains that human caretakers utilize actual words and language, but with particular inflections, which is why these whistle changes sound similar to baby babble. These inflections, which are more formally known as child-directed communication, often entail higher pitches and a larger pitch range, similar to what was seen in the dolphins' communication.

Quincy Gibson, a marine animal behavioral ecologist who was not involved in the research, believes that bottlenose dolphins are an excellent choice for child-directed or calf-directed communication. "Bottlenose dolphins are a prime candidate for child-directed or calf-directed communication," he adds. These dolphins, like people, have close relationships with their mothers and learn to communicate via vocalizations.

According to Gibson, who is the head of the Dolphin Research Program at the University of North Florida Dolphin Research Program in Jacksonville, scientists should evaluate the distinctive whistles of freely swimming, unrestrained dolphin mothers in order to validate the findings of this research. It is necessary for us to investigate this matter in circumstances that are less artificial and more natural.

No one can be certain of anything "until the day we can ask the dolphins what they're actually doing," says behavioral ecologist Mauricio Cantor of the Oregon State University Marine Mammal Institute in Newport, who was also not involved in the study. This is despite the fact that researchers speculate dolphin parentese could have the same functions as human speech.

In order to investigate the implications of this finding further, Sayigh and her colleagues evaluated the distinctive whistles of 19 female dolphins when they were either with or without their young. During catch-and-release health evaluations that were place between 1984 and 2018, audio recordings were collected from a natural population that resides close to Sarasota Bay in Florida.

The researchers listened to forty examples of each dolphin's trademark whistle, which was validated by the distinctive manner in which the frequencies of each vocalization changed over time. In the company of her young, a mother dolphin will only blow out fifty percent of her whole whistle repertoire. When there were young calves present, the mothers' whistles had, on average, a higher maximum pitch and a slightly lower minimum pitch than when there were no young calves present, leading to a wider pitch range overall.

CITATIONS

• L.S. Sayigh et al. Bottlenose dolphin mothers modify signature whistles in the presence of their own calves. Proceedings of the National Academy of Sciences. Published online June 26, 2023. doi: 10.1073/pnas.2300262120.
• H.C. Esch et al. Whistles as potential indicators of stress in bottlenose dolphins. Journal of Mammalogy. Vol. 90, June 2, 2009, p. 638. doi: 10.1644/08-MAMM-A-069R.1.