Dolphins makes their own unique whistles, and close friends and family reply with the same sound, just as humans do when we call each other by name.
Dolphins call to each other using distinctive whistles, similar to humans using proper names, a new study says.
The study, from the Sea Mammal Research Unit at the University of St. Andrews in Scotland, expands on past research that discovered that dolphins had personal whistles, but it wasn't clear until now that other members of their group learned that whistle, Live Science explained.
Dolphins identify each other by name
The research crew followed wild bottlenose dolphins off the coast of Scotland, recording the distinctive whistles known as “signature whistles” that dolphins use to hail each other. Then, using a hydrophone, the crew broadcast back those same calls altered by a computer synthesizer, so it would sound as if the familiar call was being broadcast by an unfamiliar dolphin.
When the dolphins heard a familiar name, they called back, whistling out a copy of that same name, often with additional flourishes. When they heard an unfamiliar name (the crew also broadcast the calls of dolphins that they knew to be strangers to the group), they ignored it.
If dolphins are capable of assigning and using names, it places them in a unique category, one that so far seems to be limited to humans, dolphins and parrots.
Another recent study found that dolphins call out to other dolphins that are closely associated with them within a group when they become separated. They also add their own variations to signature whistles instead of mimicking each other, as birds do.
If dolphins do indeed have a language, which studies like these increasingly suggest, it’s even more significant in light of their evolutionary journey. Like whales, dolphins were once land creatures that returned to the sea. The dolphin researcher Peter Madsen has speculated that the land-based ancestors of dolphins also produced sounds, lost that skill when they returned to the water and then evolved it again, using a completely different anatomy in their noses.
This latest study was published in the July 22 in the journal Proceedings of the National Academy of Sciences.
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