Female Bottlenose Dolphins Change Tones When Addressing Their Young

Dolphins are known for their intelligence and communication skills, but a new study has revealed that they also have a special way of talking to their babies.

Researchers have found that dolphin mothers use a kind of high-pitched baby talk when addressing their calves, a finding that may shed light on how these marine mammals learn and bond.

Signature whistles: the dolphin's name

(Photo : TOSHIFUMI KITAMURA/AFP via Getty Images)

The study, published in the journal Proceedings of the National Academy of Sciences, focused on the signature whistles of bottlenose dolphins, as per Phys.org.

These are unique and important signals that dolphins use to identify themselves and keep track of each other.

The researchers recorded the signature whistles of 19 mother dolphins in Florida, when accompanied by their young offspring and when swimming alone or with other adults. They used special microphones that were attached to the dolphins multiple times over more than three decades.

The researchers found that when directing the signal to their calves, the mother's whistle pitch was higher and her pitch range was greater than usual. This was true for every one of the 19 mothers in the study.

They suggest that dolphin mothers use baby talk to attract and hold their offspring's attention, as well as to facilitate learning and bonding. They say this is similar to how human mothers and other animals use baby talk with their young.

Baby talk: a universal phenomenon

Researchers said this is the first time that baby talk has been documented in dolphins, and they hope to further explore how it affects their development and social interactions, as per Seaworld Parks and Entertainment.

They say that baby talk may help offspring learn to pronounce novel sounds, as previous research has shown that human infants may pay more attention to speech with a greater pitch range.

They also say that baby talk may help strengthen the bond between mother and calf, as other studies have shown that female rhesus monkeys may alter their calls to attract and hold offspring's attention.

Furthermore, they mentioned that zebra finches elevate their pitch and slow down their songs to address chicks, perhaps making it easier to learn birdsong.

Also Read: 10 Disturbing Facts About Dolphins You'll Wish You Never Knew!

Calf development: a challenging process

The study also highlights the challenges that dolphin calves face in their early life.

The researchers say that dolphin calves are born after a gestation period of about 11-12 months, but some species take longer to develop than others, as per The Shark Bay Dolphin Project.

For example, bottlenose dolphin calves may suckle for up to 18 months, but may stay with their mother up to four years. For common dolphins, the calving period is between one and three years.

The researchers say that dolphin calves are born in the water, usually tail-first, and have to learn to coordinate their movements with their mother, breathe at the surface, dive, nurse, and avoid danger such as sharks.

Dolphin calves have lumps or folds in their skin at birth, which disappear within six months, and they have distinctive whistles that they use to mediate reunions with their mother after separations.

Unfortunately, dolphin calves face high mortality rates in the wild, especially in the first year of life.

There are many factors can contribute to calf mortality, such as calf condition, predation, habitat quality, prey availability, competition, environmental conditions, and human activities.

Some calves show signs of poor health prior to their death, and seek more contact with their mothers than surviving calves.

The researchers say that dolphin calves are remarkable animals that can adapt to different habitats and food resources.

However, they also say that dolphin calves are vulnerable to microparticle pollution, which may have negative consequences for their health and survival.