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Bottlenose Dolphins (Tursiops truncatus), Caribbean

Bottlenose dolphins (pictured in the Caribbean) have amazing memories, a new study says.

Photograph by Konrad Wothe, Minden Pictures

Christine Dell'Amore

National Geographic News

Published August 6, 2013

Sorry, elephants: Dolphins have taken the top spot for best memory, at least for now.

New experiments show that bottlenose dolphins can remember whistles of other dolphins they'd lived with after 20 years of separation. Each dolphin has a unique whistle that functions like a name, allowing the marine mammals to keep close social bonds.

The new research shows that dolphins have the longest memory yet known in any species other than people. Elephants and chimpanzees are thought to have similar abilities, but they haven't yet been tested, said study author Jason Bruck, an animal behaviorist at the University of Chicago. (Also see "Chimps, Orangutans Have Human-Like Memory.")

Bruck came up with the idea to study animal memory when his brother's dog, usually wary of male strangers, remembered and greeted him four years after last seeing him. "That got me thinking: How long do other animals remember each other?"

I Remember You!

Bruck studied dolphins because their social bonds are extremely important and because there are good records for captive dolphins (as opposed to wild ones).

So he 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. (Watch video: "Dolphin Talk Decoded.")

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.

Overall, the dolphins responded more to animals they'd known decades ago than to random animals—suggesting they recognized their former companions, according to the study, published recently in Proceedings of the Royal Society B.

Cheeky Dolphins

Working with animals as intelligent as dolphins was a challenge, Bruck added. The animals loved participating in the experiment so much that they'd often hover over the speaker, blocking the noise. (See "The Secret Language of Dolphins.")

Others would begin "whistling directly at me as if I could understand them," he said.

And one set of cheeky young dolphins swam up to Bruck and started whistling the names of the dominant males in their group in order of rank, perhaps suggesting the names they wanted to hear, Bruck said.

Memory Linked to Smarts?

Why dolphins—which live an average of 20 years in the wild—need long-term memory is still unknown. But it may have to do with maintaining relationships, since over time dolphin groups often break up and reorganize into new alliances.

This sort of social system is called "fission-fusion," and it's also seen in elephants and chimpanzees—two other highly intelligent and social beings. (See pictures of intelligent animals in National Geographic magazine.)

Coincidence? Bruck suspects not: "It seems that maybe complex cognition comes from a place of trying to remember who your buddies are," he said.

13 comments
Dwayne LaGrou
Dwayne LaGrou

I often wonder if it is possible to communicate with dolphins in any way such as Koko (I think that's how it's spelled) the Gorilla that can sign many words. It would be WONDERFUL if we could communicate with other sentient species. Just imagine the information we could learn about them and the other species that THEY know about. I think that would be awesome and inspiring!

Babu Ranganathan
Babu Ranganathan

NATURAL LIMITS TO EVOLUTION: Only micro-evolution, or evolution within biological "kinds," is genetically possible (such as the varieties of dogs, cats, horses, cows, etc.), but not macro-evolution, or evolution across biological "kinds," (such as from sea sponge to human). How could species have survived if their vital tissues, organs, reproductive systems, etc. were still evolving? A partially evolved trait or organ that is not complete and fully functioning from the start would be a liability to a species, not a survival asset. Plants and animals in the process of macro-evolution would be unfit for survival. For example, “if a leg of a reptile were to evolve (over supposedly millions of years) into a wing of a bird, it would become a bad leg long before it became a good wing” (Dr. Walt Brown, scientist and creationist). Survival of the fittest actually would have prevented evolution across biological kinds! Read my Internet article: WAR AMONG EVOLUTIONISTS! (2nd Edition).

What about natural selection? Natural selection doesn't produce biological traits or variations. It can only "select" from biological variations that are possible and which have survival value. The term "natural selection" is a figure of speech. Nature doesn't do any conscious selecting. If a variation occurs in a species (i.e. change in skin color) that helps the species survive then that survival is called being "selected." That's all it is. Natural selection is a passive process in nature, not a creative process.

The real issue is what biological variations are possible, not natural selection. Only limited evolution, variations of already existing genes and traits, is possible. Nature is mindless and has no ability to design and program entirely new genes for entirely new traits. Evolutionists believe and hope that over, supposedly millions of years, random genetic mutations caused by environmental radiation will generate entirely new genes. This is total blind and irrational faith on the part of evolutionists. Read my articles.

Visit my latest Internet site: THE SCIENCE SUPPORTING CREATION .

I discuss: Punctuated Equilibria, "Junk DNA," genetics, mutations, natural selection, fossils, dinosaur “feathers,” the genetic and biological similarities between various species, etc., etc.

Babu G. Ranganathan*
B.A. Bible/Biology
 
Author of popular Internet article, TRADITIONAL DOCTRINE OF HELL EVOLVED FROM GREEK ROOTS
 
*I have given successful lectures (with question and answer period afterwards) defending creation before evolutionist science faculty and students at various colleges and universities. I've been privileged to be recognized in the 24th edition of Marquis "Who's Who in The East" for my writings on religion and science.





Fredrik Asplund
Fredrik Asplund

Not too surprised by this. The brains of dolphins seems to be quite amazing indeed.

Linked on Sprawler: sprawler.tumblr.com

Robert Spreitzer
Robert Spreitzer

We can't ask them of course, but one does get the impression that they seem so much happier in the wild!

Dave Pan
Dave Pan

Just a question...when Bruck says the dolphins loved the experiment to the point of blocking the speaker, could it not be argued they were upset?  Perhaps the excitement of recognizing an old friend turned into disappointment once they realized it was fake and no longer wanted to hear these familiar sounds?

Russ Nash
Russ Nash

Well, they shouldn't be in captivity but the least they could do is give them intercoms to their old friends - even to the sea. That would be very interesting. Presumably (hopefully) the ones in captivity would warn their ocean going cousins to avoid getting captured.

Vera C.
Vera C.

Hey, National Geographic - humans are an integral part of the Animal Kingdom! We are vertebrates, mammals, primates and part of the Great Ape group.

Christine Dell'Amore
Christine Dell'Amore

@Vera Chevrolet Hart Thanks Vera, I debated that in the headline but decided it would be OK, since the term "animal kingdom" in our culture usually refers to animals other than us. But yes of course we are animals!

Juliet Morin
Juliet Morin

@Christine Dell'Amore @Vera Chevrolet Hart

While people in our culture don't generally think of humans when they hear the term "animal" used colloquially , the  term "animal kingdom" definitely seems to imply that the user is referring to Animalia in a technical sense. 

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