In a study published in Proceedings of the National Academy of Sciences, researchers identified the first nonhuman animal mother to use baby talk with their young. Bottlenose dolphin mothers use a higher pitch of their whistles when communicating with their calves. They also employ a signature whistle that functions like a name, and calves learn their names and those of their mother and members of their pod early on.

Scientists from Florida’s Sarasota Dolphin Research Program have been recording the whistles of adult female dolphins and their calves for decades. Analysis of the recordings of 19 pairs of mothers and calves found that dolphin mothers produced signature whistles with a significantly higher maximum frequency and wider frequency ranges when they were with their calves than not with them. It is thought that the baby talk enhances a calf’s attention, allowing for bonding with their mother and vocal learning. The research may provide insight into the evolution of vocal learning, a prerequisite for language.