Dolphins whistle and make other sounds to “talk” to each other. Dolphin moms use a higher pitch for their babies. (SHUTTERSTOCK)
People can tell right away when someone is talking to a baby or a small child. The person’s voice gets higher. Sometimes they talk slower or use silly sounds and words.
It turns out that dolphin mothers also use high-pitched baby talk. Researchers recently reported the findings of a long-term study on it.
Bottlenose dolphins whistle and make other sounds to “talk” to each other. Each dolphin makes what is known as a “signature whistle.” It’s like calling out their name.
“They use these whistles to keep track of each other,” said Laela Sayigh. She helped write the study. “They’re … saying, ‘I’m here, I’m here.”
Riding the Waves
A team of experts spent more than 30 years studying 19 mother dolphins in Sarasota Bay, Florida.
Over the years, they put special microphones on the same wild dolphins again and again. Some years, the mothers had babies. Other years, they didn’t.
Experts found that dolphin mothers used higher-pitched whistles with more range when calling to their babies.
Sounds are made of waves. Pitch changes depending on how fast or slow sound waves travel. Fast waves sound “high” to the human ear. Slow waves sound “low.”
Why Talk High?
Baby dolphins are called calves. In Sarasota Bay, they stay with their mothers for about three years. Father dolphins don’t help care for their children.
The research team found that mothers always changed their pitch when swimming with their young. They didn’t when swimming alone or with other adults.
“That was true for every one of the moms in the study, all 19 of them,” said Peter Tyack. He also helped to write the study.
Other animals also change their pitch when they call to their babies. Female rhesus monkeys do so. Zebra finches are birds that raise their pitch and slow down their songs.
Experts aren’t sure why animals use “baby talk.” They think it might be to help babies learn new sounds.
Listen to Mom!
Team members only studied dolphins’ signature whistles. So they don’t know if dolphins use baby talk at other times. They don’t know if it helps their children learn to “talk,” as it seems to do with people.
But there is another good reason why mother dolphins might use a high pitch. It might get their babies’ attention.
“It’s really important for a calf to know, ‘Oh, Mom is talking to me now,’” said expert Janet Mann. She wasn’t part of the study.
adj. not serious
adj. making a high sound
(phrasal verb) follow the path of something
n. variety of something