University of Chicago scientist Jason Bruck tracked the memories of 56 bottlenose dolphins and found they responded to the signature whistle of another dolphin, even if they hadn't heard the sound in 20 years, according to The Washington Post.
Bruck's research, published on Tuesday in the journal "Proceedings of the Royal Society B," found dolphins to "have the potential for lifelong memory for each other regardless of relatedness, sex or duration of association." Bruck went on to spell out the implications, writing:
"This is, to my knowledge, the first study to show that social recognition can last for at least 20 years in a non-human species. ... These results, paired with evidence from elephants and humans, provide suggestive evidence that sociality and cognition could be related, as a good memory is necessary in a fluid social system."
Dolphins have what scientists call a "fission-fusion" social life, the BBC reported, meaning they switch up their social groups much like humans have various communities to which they belong.
More from GlobalPost: In nature, dolphins whistle by name
Bruck's research showed that dolphins were capable of remembering strangers as well as relations, unlike elephants, which also have excellent memories but are only known to be able to recognize family members, according to BBC.
Even so, Eduardo Mercado III, a psychologist at New York's State University in Buffalo not associated with the study, told The Post the research is limited.
“It is in principle possible that a dolphin could find a whistle more ‘interesting’ without having any awareness of why," he said.
Bruck told LiveScience that while humans and primates are believed to have evolved such recognition capacities in order to confuse, and therefore dominate, the other, that is not a dolphin's desire.
"So we need another explanation for where the complex cognitions in these animals comes from," he said.
Here's more from the Washington Post:
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