A recent study has revealed that bottlenose dolphin mothers modify their signature whistles, akin to their own names, when communicating with their calves, exhibiting a form of "baby talk" similar to human caregivers. The phenomenon, known as "motherese" or "infant-directed speech," has been widely observed among humans, but its presence among nonhuman species has been rare.
The research, conducted by a team of scientists, highlights the remarkable similarities between human and dolphin communication patterns. Bottlenose dolphins, known for their long-term mother-offspring bonds and lifelong vocal learning abilities, exhibit changes in their vocalizations when interacting with their calves, much like the alterations seen in human motherese.
To investigate this behavior, the researchers focused on the signature whistles of female bottlenose dolphins, which serve as unique identifiers similar to calling out their own names. By analyzing recordings made during catch-and-release events in the waters near Sarasota Bay, Florida, the team compared the vocalizations produced by female dolphins in the presence and absence of their dependent calves.
The findings demonstrated that when accompanied by their offspring, female dolphins increased the maximum frequency and frequency range of their signature whistles. These changes align with the higher pitch and wider range observed in human motherese. The results provide compelling evidence of convergent evolution of motherese in a nonhuman mammal and support the hypothesis that this form of communication facilitates bonding and vocal learning, both in humans and dolphins.
While the study focused solely on signature whistles, it remains unclear whether dolphins employ baby talk in other types of vocal exchanges or if it aids in their calves' language acquisition, as it does in humans.
This research adds to the growing body of evidence suggesting that dolphins serve as a valuable animal model for studying the evolution of vocal learning and language. Previous studies have shown that dolphins respond to their own unique signature whistles, behaving as if they are responding to their names. These findings, combined with the recent discovery of motherese in dolphins, highlight the sophisticated communication abilities of these marine mammals and their potential similarities to humans in terms of vocal communication and social bonding.