Dolphins can remember an old friend's whistle even after 20 years of being apart, according to Science Mag.
A press release published by the University of Chicago confirmed that dolphins have the longest social memory ever recorded among all species excluding humans.
According to HNGN, dolphins are known for having long-term memories that have surpassed other mentally sophisticated animals likes chimpanzees and elephants.
Jason Bruck, leader of study and a PhD holder from the University of Chicago's Comparative Human Development Department, told HNGN that dolphins operate cognitively that is also very consistent with the human's social memory.
The research analyzed 53 bottlenose dolphins from a breeding consortium which often rotates the dolphins' tank-mates. Reports regarding the shuffles were properly monitored.
Bruck told HNGN that it is impossible to do the same kind of study among animals in the wild because it is imperative that the researcher know how long animals have been apart.
Studies from the past confirmed that each dolphin has a unique whistle which they use to name themselves so they also respond to their friend's whistles differently.
Bruck also told HNGN that dolphins get bored easily when listening to whistles of the dolphins they do not really know.
He recorded each of the dolphin's whistles and played it several times.
Bruck further lamented that if the dolphins are familiar with the sound of a particular whistle they listen very carefully and hover around.
He also noticed a pattern that dolphins reacted to familiar calls and whistles with more enthusiasm compared to unfamiliar ones.
He told HNGN that the conclusion of his research is that dolphins are able to maintain life-long social memory up until they are 20 years old.