A memory like an elephant
We could replace ‘a memory like an elephant’ by ‘a memory like a dolphin’.
New research has shown that they remember their friends’ sounds after not having heard it for 20 years. That proves that they have the best social memory of all non-human species.
Jason Bruck, a famous researcher of animal benaviour, came up with the idea to study animal memory when his brother's dog, usually not happy of male strangers, remembered and greeted him four years after last seeing him. "That got me thinking: How long do other animals remember each other?"
I Remember You!
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Bruck studied dolphins because their social bonds are extremely important. He collected data from 43 bottlenose dolphins at six facilities in the U.S. and Bermuda. They work together and have swapped dolphins for decades and kept careful records of each animal's social partners.
He first played recordings of lots of unfamiliar whistles to the dolphins in the study. The dolphins soon got bored. Then he played the whistles of old friends.When the dolphins heard these familiar whistles, they would be happy and approach the speakers, often whistling their own name and listening for a response.
Their memory goes back a long time: Dolphin Bailey got to hear the whistles of Allie. They hadn’t seen each other 20 years and 6 months.He recognized the whistle immediately.
There are also stories about elephants who recognize their mother after 20 years, but we cannot compare this to the dolphins because in the elephants’ cases it was about family ties. They dolphins recognized random friends.
Cheeky Dolphins
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Working with animals as intelligent as dolphins was a challenge, Bruck added. The animals loved participating in the experiment very much.
One set of cheeky young dolphins swam up to Bruck and started whistling the names of the dominant males in their previous group in order of rank, perhaps suggesting the names they wanted to hear, Bruck said.
Why dolphins need long-term memory is still unknown. But it may have to do with maintaining relationships, since over time dolphin groups often break up and reorganize into new ones.
