If you encounter someone on the street after twenty years with whom you were in the same classroom, would you still recognize the person from his or her voice? Dolphin has a long social memory and do recognize old friends. This was discovered by the American biologist Jason Bruck when the dolphin sounds in aquariums uttered by former group members. His research is described in Proceedings of the Royal Society. 43 dolphins involved in the research of Bruck. They all lived for years in captivity. It is common for marine mammals move from one to another aquarium. That gave the opportunity to watch the amount of time animals had ever lived by knowing each other. In the same aquarium Dolphins recognize each other by their ‘ name ‘, a characteristic whistle for every individual dolphin. The biologist played several such whistles off in the abodes of the animals through an underwater speaker. Bruck calculated as the degree of recognition and the extent of which the animals turned their attention to sound. Dolphins were clearly more interested in sounds of dolphins they knew than in those of unknown dolphins. She then came close to the example speaker and touched him too. At the sound of strangers they did not pay any attention. It turned out not to matter how long the dolphins had lived separated in all this. The animals reacted to the whistle of co specifics they already had not seen or heard for twenty years.
Animals with Social Memory
Brucks study provides additional evidence for the idea that recognition of peers is very important for social animals. And dolphins play the seventh species has been scientifically proven that they can relate after a long time together. The other six to recognize each other are crows (with a social memory of at least 3 years), Japanese macaques (4 years), the Campbell meercat (4 years), elephants (over 10 years), hyenas (at least 1 year) and of course humans.