Hello, My Name Is Dolphin: The Mammal That Never Forgets

Our oceangoing cousins show an astonishing memory for names

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In his Hitchhiker’s Guide to the Galaxy books, the late, great British satirist Douglas Adams wrote that dolphins are the second most intelligent creatures on earth — before humans and after mice, which spend their time running complex lab experiments on scientists. The mice might not quite live up to their No. 1 billing, but the more we learn about the cognitive abilities of dolphins, the more they indeed seem to have the No. 2 spot locked up. Not only do dolphins have impressive memories for tasks, the ability to use tools and elaborate social structures, but they also have their own names, distinctive identifying whistles that they develop themselves. Now a study in Proceedings of the Royal Society B reports that dolphins can recognize the whistles of others they shared a tank with as long as 20 years ago, the most enduring social memories ever observed outside of humans.

The study, undertaken by Jason Bruck, then a graduate student at the University of Chicago, used 43 dolphins ranging from 4 months to 47 years old that are cycled among various institutions as part of a captive breeding program. Some of them had lived together for only three months; others had shared a tank for more than 18 years before being separated. Bruck first obtained recordings of each dolphin’s name whistle. Then he set up an underwater speaker in the dolphins’ tanks that played whistles from strangers and from former tankmates. The difference in the dolphins’ reactions was unmistakable.

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“When they hear a dolphin they know, they often quickly approach the speaker playing the recording,” Bruck said in a prepared statement. “At times they will hover around, whistle at it, try to get it to whistle back.” They paid far less attention to a stranger’s whistle-name.

Moreover, it didn’t matter how long the animals had been separated — a dolphin could recognize the call of a companion it had last seen decades ago just as easily as one it last saw six months ago. Nor did it matter how short or long the animals had been housed together; they responded with the same recognition to a long-term friend or a more fleeting acquaintance. In the most impressive case, a dolphin named Bailey recognized the whistle of Allie, her tankmate 20 years and six months ago. “This shows us an animal operating cognitively at a level that’s very consistent with human social memory,” Bruck said.

Wild dolphins have a life expectancy that ranges from 20 to 50 years (though such superannuated adults are rare), and they live in ever shifting pods, with individuals constantly splitting off and reuniting with the group. Bruck suggests that animals with such a social structure may benefit from a long memory for one another, perhaps supporting a connection between complex social behavior and the evolution of memory. But it may also be that a prodigious memory for names is just part of the larger, fascinating package of dolphin intelligence, included for no particular evolutionary reason — another element of the hidden depths of a mammalian cousin that we continue to explore.

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12 comments
CherieGrayLester
CherieGrayLester

How incredibly sad.  What would it be like if we were locked in a room our entire life, had friends introduced to us then ripped away and then had someone play their voice back to us almost as a cruel joke?  These intelligent, amazing, complex and compassionate creatures have a right to live in their natural environment and we have an obligation to see to it that they do - and also to make sure that their natural environment is clean and pollution free. 

ramfroggie
ramfroggie like.author.displayName like.author.displayName 2 Like

So they are so intelligent...which I so agree with...but instead of respecting them as our colleagues and equals (or better, in my view, since they aren't fouling the planet or forcing humans into little pens) we treat them horribly and kill them as if they are garden slugs.  What does that say about us as a species?  I know that some are rescued from various emergencies and rehabbed, but still...intelligent.  They form such bonds and instead of wondering if they miss those friends/family they were ripped from, humans just say hey, they recognize each other.  I say duh.  Of course creatures with such complex systems of communication and who play, bond, and are so intelligent know each others' voices.  Communication is how they survive...why on earth wouldn't they remember each others' names?  We humans need to step back and look at how arrogant we are.  We take such intelligent animals (just as we are, supposedly) and keep them in little tanks, separate them from their family and companions,  and we disrespect that they aren't meant to be trained domesticated dogs.  

How sad.  What a horrible statement about us.  We assume we are the ones who are amazing, but look how we treat other animals and the whole planet.  Ever hear of a dolphin attacking swimmers near the shore?  Just randomly killing them?  No, despite the fact that they are totally capable of it.  Guess they didn't consider that the dolphins coming to the speakers were excited a loved one might be there and then sad and confused.  Perhaps I could play their deceased grandmothers' voices over a speaker and see what they do.  Sad.  Just sad.

Aletheya
Aletheya like.author.displayName like.author.displayName 2 Like

So ... keeping dolphins (and whales) in captivity in small, bare tanks, amounts to slavery and cruel & unusual punishment.  Like keeping a person prisoner in a small, bare closet.  And killing them, particularly barbaric practices such as the japanese community that traps entire pods in a bay and then brutally stabs them all to death, turning the water red with blood as the dolphins scream, is nothing else but murder.  Such compassionate creatures we humans are.

shoos
shoos like.author.displayName like.author.displayName 2 Like

They have discovered such high intelligence in these animals, yet still they have no qualms about the captivity.  It would be a much more interesting article if the reporter to ask the researchers these kind of questions. Some of this research seem almost inhumane, since they have proven how evolved their social bonds seem to be.   

shoos
shoos

decided to ask...sorry missed a word.

oksunny
oksunny

As for the grammar, I noticed that too...

oksunny
oksunny like.author.displayName 1 Like

This is SO sad to me. Just because they can't walk or talk (like humans) they are forced to succumb to our whims. 

Moving them around like they do, is like coming home to your mother/father/husband/wife/son/daughter just vanished....

Akela
Akela

It's hard to get anything out of an article with bad grammar. It's careless and implies the information is sloppy too.

AlfredoSitarosa
AlfredoSitarosa like.author.displayName like.author.displayName 2 Like

Very poor grammar!  Wow where do they find editors like this?  Sad.


"The mice might not quite LIFE up to their number one billing....


they also have their own names, distinctive identifying whistles they DEVELOPED themselves.


mefoster86
mefoster86 like.author.displayName 1 Like

Agree on the "life" part, but using "develop" makes sense. It doesn't need to be past tense. For example, "Parents name their children." If you aren't referring to specific individuals (just dolphins in general here) it's correct.

JenniferAldoretta
JenniferAldoretta like.author.displayName like.author.displayName like.author.displayName 3 Like

Dolphins are fascinating, but I always find it difficult to continue reading an article when there's a vocab error in the first two sentences.

AlfredoSitarosa
AlfredoSitarosa like.author.displayName like.author.displayName 2 Like

@JenniferAldoretta I agree, if they don't know how to pay attention to details such as spelling, well, what does that say for they facts they supposedly gathered.  I lost faith too.