Dolphins Tell Each Other Apart by Their Whistles

Characters like Mickey Mouse and the seven dwarves have signature whistles. It turns out dolphins do too. But dolphins don't use them to grab attention or pass the time while they work. Instead, they use their whistles to identify themselves, according to scientists.    

Dolphins’ unique whistles are like their names. Researchers have studied the sounds they make for more than 50 years. However, a study published Thursday in the journal Scientific Reports finds two conditions that influence these sounds: dolphins’ specific habitat and pod.  

The study showed those who swim in seas with more seagrass have shorter, higher pitched whistles than those who swim above muddier ocean floors. Dolphins that swim in small groups change their whistles’ pitch more than those in large groups, according to the study.  

Dolphin whistles are "often said to be similar to a name." That's according to Brittany Jones, a researcher who spoke with NBC News. Jones studies marine mammals. 

Jones added that dolphins use their whistles more than humans say their own names. It's how they identify themselves. A 2013 study found that dolphins will use the whistles of other dolphins to try to contact them.

Researchers believe dolphins have good long-term memories. Dolphins, they say, can recall other dolphins from the sounds they make even after twenty years without contact.  

Photo from Arnaud 25 courtesy of Wikimedia Commons.