Forget Elephants! Dolphins Have the Longest Memory

Scientific Minds Want To Know

Forget elephants! A new study has shown that bottlenose dolphins have the longest memory in the animal kingdom.
Each bottlenose dolphin has a unique whistle that fuctions like a name. Research by Jason Bruck, animal behaviorist at the University of Chicago, shows that dolphins remember the unique whistles of other dolphins they've lived with, even after 20 years of separation.
Bruck got the idea for the study when he visited his family and was greeted by his brother's dog, who is usually wary of strangers. The dog remembered him from Bruck's last visit four years ago. That got him thinking, "How long do other animals remember each other?"
Dolphins, it turns out, are the perfect test subject. According to Christine Dell'Amore of National Geographic News:

[Bruck] collected data from 43 bottlenose dolphins at six facilities in the U.S. and Bermuda, members of a breeding consortium that has 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 until the subjects got bored and stopped inspecting the underwater speaker making the sounds.
At this point, he played the whistles of the listening dolphins' old friends.
When the dolphins heard these familiar whistles, they would perk up and approach the speakers, often whistling their own name and listening for a response.

Furthermore, it seems like the dolphins actually enjoyed hearing whistles from their old friends. Bruck added that a set of cheeky young dolphins came up to him and whistled the names of other dolphins they wanted to hear next.
Read the rest over at National Geographic