Among non-human species it is dolphins that have been found to have the longest social memory. Scientists found that they can remember each others whistling calls even after twenty years of separation.
Among the most intelligent creatures, apart from human beings, are dolphins. A University of Chicago researcher made a startling discovery when he found that dolphins can recognize each others signature whistles even after two decades of being kept apart. This places them in the selfsame category as chimpanzees, elephants and human beings. The pattern of a dolphin’s signature whistle remains the same over time.
Human facial recognition is not as reliable since a person grows old or obese with time. But these fascinating marine mammals keep their distinctive calls over a fairly long period of time. The experiments were carried out with many dolphins that had been moved for breeding purposes. The dolphins refused to respond to a whistle from an alien dolphin. Yet when they were offered whistles from dolphins they had once been living with, they responded eagerly.
We need to find out if the same behavior occurs in real life conditions rather than in captivity. But to be able to do that would require far more complex heuristics. The species that was experimented upon was the bottlenose dolphin. The remarkable memory banks of these wonderful creatures outranked the elephant which is said to never forget a thing. The findings have corroborated something humans knew all along: animals are not dumb. They just have a different mode of consciousness and senses from human beings.