A new study has found that dolphin mothers also use a kind of high-pitched baby talk with their kids.
Researchers from the University of Southern Mississippi and the University of California, Santa Cruz, recorded the vocalizations of bottlenose dolphins in Sarasota Bay, Florida, and analyzed how they changed over time.
They found that dolphin mothers used a special type of whistle, called a signature whistle, to communicate with their calves. Signature whistles are unique to each dolphin and serve as a way of identifying themselves.
The study, published in the journal Animal Behaviour, revealed that dolphin mothers modified their signature whistles by making them longer, simpler and more repetitive when they were with their calves. The researchers suggest that this may help the calves learn their mothers’ whistles and respond to them more easily.
“We think this is very similar to the way humans use baby talk or motherese with infants,” said lead author Audra Ames, a doctoral student at the University of Southern Mississippi. “It’s a way of simplifying and exaggerating speech to attract attention and facilitate learning.”
The researchers also found that dolphin mothers used their signature whistles more often when they were separated from their calves by more than 10 meters, indicating that they were trying to maintain contact and ensure their safety.
“Dolphin calves face many threats in their first few years of life, such as sharks, fishing gear and boat strikes,” said co-author Rachel Cartwright, a lecturer at the University of California, Santa Cruz. “By staying close to their mothers and learning their whistles, they can avoid these dangers and increase their chances of survival.”
The study is one of the first to document how dolphin vocalizations change over the course of development. The researchers hope that their findings will shed more light on the complex communication and social behavior of these intelligent marine mammals.