Dolphins' elaborate octopus-hunting strategy

https://arstechnica.com/science/2017/04/new-study-reveals-dolphins-flinging-octopuses-into-the-air/

by shawndumas • 9 years ago

301 187 9 years ago

custos• 9 years ago

This makes me think of primitive humans working together to kill large animals for food.

Super dangerous and only possible when working together.

Perhaps one day, thousands of years from now, technologically advanced dolphins will one day watch us doing the same thing again, and they will have a similar article about us!

npongratz• 9 years ago

Perhaps one day, thousands of years from now, technologically advanced dolphins will one day watch us doing the same thing again, and they will have a similar article about us!

I'd be curious to know how much of human technical advancement was thanks to the ability to relatively easily smelt metal, and whether the inability to easily smelt underwater creates an impediment to technical advancement of species living underwater.

maxerickson2• 9 years ago

Humans were doing pretty good already in the late stone age.

stcredzero3• 9 years ago

Seawater also plays hell with ropes and hide. You can't construct with stone, because it sinks to the bottom, and the silty bottom is a rotten foundation. You can't build with wood because it floats away, it will soften and weather quickly, and things will eat it quickly. You can't wear tools, as that ruins your streamlining, and fast swimmers will generate high drag forces on anything they wear.

The ocean isn't a good place for tool building!

eru7• 9 years ago

Humans were already pretty handy with wood, leather and stones. No underwater species has made it that far.

(No idea whether there's any wood equivalent underwater.)

dom02• 9 years ago

Eh, smelting metal isn't easy. Even primitive smelting and forging is complex and needs a lot of experience to get right.

maxxxxx2• 9 years ago

I think this very possible. Maybe not a thousand years but give it a few million.

erikpukinskis7• 9 years ago

We will be able to speak with dolphins within 40 years because of augmented reality. 20 for the hardware/software foundation and 20 to raise adolescents who are adapted the augmentation.

The only reason we haven't been able to communicate with them is we haven't found a good mutually comprehensible input medium for them. HMDs could be it, positional audio might help. But either way VR as a metaphor for UI will get researchers thinking in new ways about input as we go deeper into VR ourselves.

Presence will be the Rosetta Stone for animal language. "You are here and this is happening" is orders of magnitude harder to ignore as an atom of communication than a computer screen on the wall of a talk.

We will be able to record entire naturalistic experiences of a dolphin, and then give them an AR keyboard to play back arbitrary slices of it in sequence, and do the same for their friends.

Early dolphin language will look like hip hop music or poetry in structure (a pastiche of samples), and we will quickly find out whether they have the neuroanatomy for grammar.

coldcode• 9 years ago

Then they will take our spaceships and leave the solar system and thank us for the fish.

xherberta2• 9 years ago

You say "the only reason," but I'm not sure.

I think one barrier may be that we're not that interesting to them. Perhaps, rather than sending literal-minded scientists to attempt communication, we ought to send poets and musicians.

I read of a recording of an upset, irate dolphin's sounds. When slowed down significantly, it was clear the dolphin was mimicking it's trainer's reprimands. So, one clue is that their processing speed is way higher than ours.

I also read of a researcher who set out with a box that could make dolphin sounds, and she wanted to teach dolphins to say names she has made up for three objects, with disappointing results. But I'm wondering... these are creatures that can be taught a command that means "innovate" - do something different that you haven't shown me yet today. A rule of their language might be never to use the same word twice.

Also, dolphins are aware of one another's sonar. So, they would never need to vocalize "Look at that over there." They already know what pod-mates are paying attention to. Possibly they wouldn't find it interesting to use nouns to refer to things that are already obvious on the pod's echolocation radar. Their verbal channel might deal with less concrete things like mood, nuance, intuition, and humor.

londons_explore• 9 years ago

It seems surprising that an octopus leg hitting the oceans surface 15 times kills it.

I can't imagine that a dolphin can throw an octopus leg at more than 15-20 mph, and at that kind of speed I wouldn't imagine damage to a soft bodied creature.

I would imagine a better technique to be to leave the octopus legs for 10 minutes for lack of bloodflow to kill it. Wonder why they don't do that? Too hard to defend a bleeding morsel of food from other predators?

quotha2• 9 years ago

You try doing that, eat it, and see what happens

steffan• 9 years ago

I suspect the defensive mechanism in the octopus leg is triggered by the impact. After a number of impacts the remaining energy in the leg is exhausted and it can no longer harm the dolphin.

lnanek2• 9 years ago

If you watch the video, it's not just throwing the leg, there's also a behavior where they hold the legs in their mouth and slam it into the ocean as hard as they can by bending sideways. Considering dolphins use those muscles to swim, they are likely very strong, considerably stronger than human arms tenderizing meat with a mallet like we do.

I don't see why you would think leaving the legs alone for ten minutes would be as effective as hammering them for ten minutes. What's going to bleed out and go lifeless quicker, an arm left alone or an arm being beat on?

dogecoinbase• 9 years ago

Always impressive to see HN find unbroken ground for the expert fallacy.

garaetjjte• 9 years ago

I would imagine a better technique to be to leave the octopus legs for 10 minutes for lack of bloodflow to kill it.

Arms work even 1h after cutting off: http://moscow.sci-hub.cc/58b56284136af39dc0eaf7491b31d759/ha...

0xfeba• 9 years ago

Interesting survival technique, if I can assume it is. The octopus in question dies but the dolphin who tried to eat it does also. Serves as a warning to dissuade eating the species/order as a whole. Same as poisoned toads in that regard, just a little more zombie-like.

random_rr• 9 years ago

Something about a human imagining a "better" strategy for a dolphin is very humorous to me.

awjr• 9 years ago

Sprogis and colleagues muse that the nutritional value of an octopus must be "substantial." Or, as marine biologist Holly Bik points out at Deep Sea News, maybe it's just that "dolphins are a$$holes."

Best line from the article :D

quotha2• 9 years ago

or the worst line

erikpukinskis7• 9 years ago

I didn't get it

tetraodonpuffer2• 9 years ago

It's still unclear why dolphins are willing to risk so much for such a small meal.

maybe it's just they like the taste? it's not like we don't go out of our own way to find some delicacies just because we are in the mood for them.

I know anthropomorphizing animals is a no-no these days, but trying to explain everything based on "nutritional value" seems a bit narrow minded...

rwc• 9 years ago

Why is it a "no-no these days"?

euyyn• 9 years ago

It's a no-no always because it's poor reasoning. Saying "these days" is a way to paint it as some kind of fashion above which the commenter is. In this specific case, I reckon dolphins have taste buds too, so it isn't really anthropomorphizing. I think it's a good hypothesis.

clydethefrog• 9 years ago

I would even argue it's the opposite. The book by biologist Frans de Waal - Are We Smart Enough to Know How Smart Animals Are?[1] was in a lot of best book lists.

[1] See a review about it that explains his findings. https://www.theatlantic.com/magazine/archive/2016/05/how-ani...

cmdrfred• 9 years ago

Perhaps the nutritional value is why it tastes good to them from an evolutionary standpoint.

zenlikethat• 9 years ago

Yup, that's why we like sweet food, because once upon a time it was few and far between, so you darn well better eat it when you come across it.

fredley• 9 years ago

Humans will risk death to ingest or otherwise put things in their body, but not usually because they're tasty, usually because they're addictive.

Do dolphins get high on octopus?

Nadya• 9 years ago

Some potentially deadly foods are considered a tasty delicacy. See, fugu [0]. Which can be really, really really poisonous [1]. It makes cyanide seem harmless in comparison.

Although I just learned from Wikipedia that apparently we figured out how to raise non-poisonous pufferfish. Neat.

[0] https://en.wikipedia.org/wiki/Fugu

[1] https://en.wikipedia.org/wiki/Tetrodotoxin

pvaldes5• 9 years ago

Not. They don't get high on octopus, they feast on octopus and also play with its preys.

got2surf• 9 years ago

Not sure about octopus, but dolphins do get high on pufferfish - http://www.smithsonianmag.com/smart-news/dolphins-seem-to-us...

"Pufferfish produce a potent defensive chemical, which they eject when threatened. In small enough doses, however, the toxin seems to induce "a trance-like state" in dolphins that come into contact with it"

ptha• 9 years ago

There are reports of dogs repeatedly licking the toxic cane toads in Australia. Some are speculating the dogs are "addicted" to the "high" from a non-fatal dose of the toxin the toads excrete in their sweat. http://www.huffingtonpost.com/2013/12/17/dogs-licking-cane-t...

SilasX• 9 years ago

"Why does my cat keep bringing back dead mice? He doesn't need to hunt, I give him all the food he needs!"

'Why do you keep having sex? You already have all the kids you want!'

circlefavshape• 9 years ago

Or hunting something dangerous is just fun?

vinchuco3• 9 years ago

Do they compete for the same food?

glenstein• 9 years ago

I know anthropomorphizing animals is a no-no these days

Well, I think you are making a good point here, so I wouldn't write it off on that basis. In the rush to avoid anthropomorphizing animals, people sometimes go to the opposite extreme and assume that things like "taste" are uniquely, exclusively human experiences and can't be extended to animals.

That seems to attribute full ownership of a category of experience to humans, and to me that kind of assumption is more problematic, if we're talking about the excesses of anthropocentrism. I think your explanation makes perfect sense.

m_fayer• 9 years ago

Any dog owner can tell you stories of the lengths to which animals will go for food that they find particularly tasty.

maxxxxx2• 9 years ago

I have seen dolphins swim in the wake of a ship and I strongly believe they did it just for the kick of it. Maybe they showed off to the dolphin girls, who knows?

pvaldes5• 9 years ago

I think reading the article that the risk is much overstated for sexy story-telling purposes. Dolphins of course do not choke if their mouth is full or blocked. They breath by the spiracle in the top of their head.

mzzter• 9 years ago

"Art of the octopus smackdown" haha very colorful writing

sevensor• 9 years ago

I once saw fresh octopus prepared at a seaside barbecue place. The first thing the octopus did after the cook grabbed it from the kiddie pool full of seawater was to wrap its tentacles around her forearm. Before it could get too firm of a grip, she threw it down on the concrete floor with a loud smack and disassembled it with a cleaver while it was still stunned. It was pretty intense. I can see why the dolphins would have a complex strategy for dealing with the much larger octopus they consume.

Now that it's become clear that the octopus is an intelligent creature capable of solving problems and making plans, I'm going to eat less sophisticated mollusks and leave octopus to the dolphins.

overcast• 9 years ago

I feel bad about eating intelligent species, however if it makes you feel any better, their lifespan is only 3-5 years.

roberto• 9 years ago

Relevant SMBC: http://www.smbc-comics.com/comic/moral-relativity

mmjaa2• 9 years ago

I'm with you, I can't stand the thought of eating them. They're just too darn smart, and seem really aware of you. I've swum all over the world, and any time I get a chance, I'll easily change my plans just to hang and watch a cephalopod in the wild. Thing is, too many times I've felt the situation reversed - that I'm swimming along, and the octopus are watching me, hanging out, trying to learn what this strange creature is up to in their ocean.

cannonpr• 9 years ago

I used to love eating octopus particularly in sashimi form or nigiri, after learning more about their intelligence and behaviours I find my self increasingly unable to eat them... While I understand why I have developed this response in respect to a relatively intelligent animal... it's a shame because they really are so damn tasty. In other words I totally get the dolphins.

ajuc• 9 years ago

I'm pretty sure pigs are smarter still.

lorenzosnap• 9 years ago

agreed. no more octopus with potatoes for me. they are too clever. I will just eat the potatoes.

TurboHaskal• 9 years ago

I suddenly feel the need of reserving a flight to Galicia after reading your comment.

vinchuco3• 9 years ago

You're assuming potatoes aren't clever too (albeit obfuscated in some way or over a larger time scale )

terryf• 9 years ago

Maybe that's exactly what they want you to think and they really are just out to get the potatoes, which they don't like!

qyv• 9 years ago

Dolphins, which are another highly intelligent species, don't seem to have any qualms about eating octopus.

db48x• 9 years ago

Yes, but we don't eat dolphin because we regard them as too intelligent (unless they spend all their money on the lottery).

muninn_• 9 years ago

Dolphins most likely don't have any notions of ethics.

afterburner2• 9 years ago

Neither do many humans.

But there are many, many differences between humans and dolphins. We're smarter, for one. Debate philosophy. Are rarely seriously in danger of starving. Have much more culture. Etc., etc.

self_assembly• 9 years ago

Dolphins also don't seem to have qualms about raping and other violent behavior. I don't think humans should base their ethics around what a dolphin would do.

probablah3• 9 years ago

Dolphins are clearly intelligent, but not smart enough to organize a colony of many thousands of permanent shelters, and share community surplus that advances a dolphin civilization that benefits those who participate.

So, probably as intelligent as nomadic pre-historic humans. I wouldn't rate that as "highly" intelligent. Just somewhat intelligent.

These are still pre-historic dolphins, since they don't seem to record history for themselves yet. If they carry oral traditions, they seem to be limited to hunting techniques, and not specific events and personalities measured across time. There is no evidence of symbolism invented by dolphins.

eru7• 9 years ago

Pigs are also pretty smart. And still delicious.

jjtheblunt• 9 years ago

Just like humans, said every cannibal ever.

whyenot• 9 years ago

So are dogs, depending on who you ask.

virtuabhi4• 9 years ago

I really don't get why this reasoning is not extended to other animals as well. For example, people do eat cows, pigs, dogs and they are pretty smart as well (much more than plants). I think it boils down to "culture" of the place you grew up. Maybe in your country people never ate octopus but in country X (China? Korea?) they never had any doubts about eating octopus.

ep103• 9 years ago

eating dogs is insane.

Pigs are very smart, but they're also probably _the_ most delicious meat. Its unfortunate.

Cows, I think, most people assume are stupid?

mmjaa2• 9 years ago

I've seen Octopus using tools.

I'm from south-west Australia (where these dolphins were observed) and grew up swimming along the coast, scuba and snorkelling to much delight.

Once, in a little sand hole near Yanchep, I was floating around on a particularly hot day, when I thought I saw a crayfish just lolling around on the ocean floor. Diving deeper to get a closer look, I realised it was just the head of the crayfish, long-since hollowed out, albeit with a bit of flesh still onboard.

I took an even closer look, and what I thought was a bit of weed attached to it was actually a long, slender tentacle, which I followed back to a minuscule hole in the rocky sand, and therein I spotted the rest of the octopus.

Delighted, I stuck around for a while to watch.

The octopus was fishing! It held out the cray corpse just a little, out in the currents, waiting patiently for the stupid little white fish to come and try to nail a bite!

When a particularly dumb little fish got its fangs in, BAM! Out came another tentacle, fast as light, and snatched that dumb fish into the hole. All the while, the original bait tentacle continued to just lull about, swinging and swaying, getting those dumb fish even closer and closer, ever more tantalising.

I stayed and watched it all day - it apparently had a nearly-insatiable hunger, or maybe it was just really enjoying itself. To my dying days, I'll never forget that clever little cephalopod ..

max_• 9 years ago

May be zoologists have been underestimating the intelligence of mollusks

macintux3• 9 years ago

We've known for a while that octopuses are surprisingly intelligent. Great read: https://orionmagazine.org/article/deep-intellect/

(tl;dr: don't eat octopus!)

TuringTest5• 9 years ago

I doubt that. There are huge batches experiments (performed by zoologists) experimenting the limits of octopus intelligence. Some have demonstrated that their tentacles have some limited brain power on their own, being able to perform some limited reasoning and problem-solving when isolated from the central brain.

oh_sigh2• 9 years ago

I dunno...gastropods do seem pretty dumb. Cephalopods are where the money is at.

Cuttlefish!

bsder• 9 years ago

Or perhaps we overestimate the intelligence of mammals.

hellofunk• 9 years ago

One more reason why I realize how similar I am to a dolphin. You have no idea how many times I have risked my life so I too could eat octopus.

gigatexal• 9 years ago

The octopus and likely the dolphin is probably much smarter than we give them credit for. On a whim one day I studied the octopus and finding them majestic and so smart I stopped eating them. The kicker was when I learned that female octopus when giving birth find a rock out of sight of predators and spend their last days and minutes doing nothing (no eating etc) but waiting for the next generation to birth and then they subsequently die. It was moving.

munificent2• 9 years ago

I'm probably missing something obvious, but... why don't the dolphins just chew their food better?

SolaceQuantum• 9 years ago

Dolphins haven't developed the kind of jaws necessary to chew substantially like a human, who chews with molars. Also humans still can choke to death on octopus.

nkristoffersen• 9 years ago

And pretzels :-)

ionwake• 9 years ago

I wager that the whole purpose of throwing the tentacles into the air is to provide the dying organism with a lack of stimulus to the neurons in the tentacles for a few seconds, on water impact, the renewed stimulus would make the tentacles move. I reckon after a few tries the tentacles just run out of energy.

This is just a thought and may not be correct.

astrodust5• 9 years ago

They don't chew. Chewing is what land animals who eat leafy plants do.

They can bite, and that's about it. Do these look like chewing teeth? http://4everstatic.com/pictures/674xX/animals/aquatic-life/d...

munificent2• 9 years ago

Ah, of course. That makes sense. :)

zeristor• 9 years ago

David Brin's series the "Uplift War" had a backdrop to human's raising the intelligence of a number of Earth origin animals.

How I wish he had the human society uplift the Octopus instead of the expected mammals.

astrodust5• 9 years ago

They would've taken over the world!

dom02• 9 years ago

Hail Hydra!

Cpoll• 9 years ago

It's not clear to me that they're "risking death."

The article reveals that dolphins can be killed trying to eat octopus in a more conventional fashion, but I don't see any "risk" involved with their throwing method.

astrodust5• 9 years ago

They might be teenaged dolphins that do things on a dare. They're smart and they get bored.

khedoros1• 9 years ago

What about if they don't throw it enough times to stun it? Or if that particular octopus is particularly stun-resistant? Or if the dolphin hesitates at some point in the grab-and-throw maneuver, giving the legs a chance to grab on to its face, mouth, or throat? It seems like there would be a lot of opportunities for error.

awinter-py• 9 years ago

Hmm -- I didn't think dolphin airways were connected to their digestive system.

wungsten• 9 years ago

You're right, they're not. I wonder what the cause of death was, then.

telesilla• 9 years ago

I've seen this behaviour with seals when kayaking. Fascinating to watch, and I swear they were just showing off to us bunch of humans hanging out enthralled by the sight of a large seal slamming the octopus over and over again against the water until it was dead enough to disappear with back into the deep.

metricodus• 9 years ago

I would like to challenge my hard-core religious physics and biology teacher from 7th grade with this evidence. He kept giving me as low a grade as what was acceptable, while I still aced pretty much every test. (Sweden. Småland. 90s. I don't think this is an issue for todays kids.)

itchyjunk• 9 years ago

I thought the brain:body size rank was Humans, chimp then dolphins but looks like I am wrong about it[0].

https://en.wikipedia.org/wiki/Encephalization_quotient

xHopen• 9 years ago

The full article is just amazing, http://onlinelibrary.wiley.com/doi/10.1111/mms.12405/full I love and fear dolphins at the same time

I will totally continue eating octopus

Dolphins' elaborate octopus-hunting strategy

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