Wild Dolphins Assign Unique Whistle "Names" to Call Each Other

A new study has shown that wild bottlenose dolphins have unique whistles that they use to call out "names" of their relatives.

The latest study conducted by researchers from University of St. Andrews in Scotland found that bottlenose dolphins can create unique whistles to distinguish between family and strangers and can even recognize their own sound, reports Smithsonnian.com. 

Dolphins are unique creatures; they can not only solve complex math problems but are also self-aware with complex personalities. Dolphins are known to take special interest in knowing pregnant women and help people from sharks.

However, they are also known to kill for fun and even assault divers. This new study found that some dolphins call each other by unique names further adds to the growing literature that supports the idea that dolphins are non-human people.

There are birds and other mammals that can identify objects using vocal recognition. This behavior is usually taught by parents to offsprings. In case of dolphins, they actively assign names via unique whistles and respond to chirps of their family.

The current study isn't the first one to say that dolphins have advanced communication skills. One study reported in 2011, that dolphins don't really whistle, but rely on vibrating tissues on their nasal cavities, analogous to the human vocal chords.

Back in 2006, Stephanie King and Vincent Janik from the University of St. Andrews in Scotland found that dolphins were more likely to move towards an audio speaker that was emitting the whistles of a relative than an unrelated bottlenose. The study had shown that dolphins could be using whistles that are unique to an individual dolphin.

Recently, in February 2013, another study by King and Janik reported that mother dolphins copy their offspring's unique whistle during a separation period, which she then uses to call and locate her offspring.

The current study was conducted on wild bottlenose dolphins. Researchers collected data over a decade by following wild bottlenose populations off the east coast of Scotland and recording each individual's whistle.

In one of the experiment, dolphins were made to listen to copy of their own calls or calls made by another similar sounding dolphin or calls made by an unrelated dolphin. Researchers found that dolphins were more likely to start whistling when they heard the exact copy of their own calls rather than those of a stranger.

In another trial, researchers blindly tested their hypothesis by randomly playing records of dolphin whistles and listening to the response made by the dolphins. They then coded the two whistles to see whether they matched. They again found that the animals were more likely to "call back" when they heard their own whistle rather than other sounds.

In eight of 12 trials that was based on a member dolphin listening to its own group's chirps, at least one dolphin responded with a chirp compared with about 2 out of 22 trials where the participant dolphin was listening to chirps of unfamiliar dolphins, according to Smithsonnian.com .

Also, researchers found that dolphins moved towards the audio players when they heard their chirps being played, which shows that these animals are self aware.

Note that the experiment had its limitations. The researchers weren't sure which dolphin in the group responded to the player. But, previous work on the subject shows that dolphins can identify themselves.

Dolphins belong to the familes Delphinidae (oceanic dolphins) or Platanistidae (river dolphins). Most dolphins are small with beaklike snouts and needle-like teeth. Bottlenose dolphins are popular due to their friendliness, grace and intelligence and also because their curved faces give the appearance of a permanent smile.

The study is published in the journal Proceedings of the National Academy of Sciences.