Artificial eyespots on cattle reduce predation by large carnivores | Hacker News Reader

Artificial eyespots on cattle reduce predation by large carnivores

nature.com

254 pointsdsr12139 comments

I live in an area with native Cougar and Bear. Local hunters told me a couple decades ago the best thing to do in the woods when you are alone is to put your sunglasses on the back of your head. They explained that large cats typically attack from behind. When the glasses are on the back of your head it confuses the cat as to which direction you are looking and makes them hesitate (therefore less likely) to attack you.

It always made sense to me. This study seems to reinforce their advice.

Tangentially related: fighter jets do this too.

Interesting how universal these tricks seem to be.

https://en.wikipedia.org/wiki/McDonnell_Douglas_CF-18_Hornet...

Awesome! This is similar to dazzle camouflage from WW1, the idea being to disguise the heading of the ship. I'm not sure it was ever shown to actually work though.

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

Dazzle was meant to fool coincidence rangefinders. The method of operation of such a rangefinder is that you see two halves of a picture, and your job as the operator is to adjust a range knob until the two halves "line up" and produce a single picture. By making parts of the ship easy to mistake for other parts, dazzle made this hard.

Dazzle fundamentally failed at this task because the primary opponent, Imperial Germany, did not use coincidence rangefinders. Instead, they used stereoscopic rangefinders, against which Dazzle had little effect. (Incidentally, the Germans also went to war with a naval camouflage paint scheme that was best designed to defeat their own instruments, and was notably less effective against the Royal Navy.)

This has me really curious about a bigger topic: “what are some massive wartime expenditures (money, resources, attention) that ended up being completely ineffective?”

Soviet anti-tank dogs [0] in WW2. Although in truth the expenditure wasn't massive.

> the Soviets used their own diesel engine tanks to train the dogs rather than German tanks which had gasoline engines.[5] As the dogs relied on their acute sense of smell, the dogs sought out familiar Soviet tanks instead of strange-smelling German tanks

[0] https://en.wikipedia.org/wiki/Anti-tank_dog

https://en.wikipedia.org/wiki/Semi-Automatic_Ground_Environm...

Cost billions; more than the Manhattan project. Obsolete soon after deployment due to ICBMs.

(Taking your "war time" to include cold war time)

My favorite example of this is the Spruce Goose.

https://en.m.wikipedia.org/wiki/Hughes_H-4_Hercules

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

The canonical example is probably the Maginot Line--to such an extent that it became a general metaphor for that sort of thing.

https://en.wikipedia.org/wiki/Stanley_R._Mickelsen_Safeguard... https://en.wikipedia.org/wiki/Safeguard_Program

Most of the German "wunderwaffe", really. The V2 programme killed more during its manufacture than it did as targets.

There is a comedic book on this called "My Tank is Fight"

On the other hand, dazzle did make the crew feel better. And the ships had to be painted anyway....

Dazzle arguably made incidence range finders more effective, providing more edges to align.

Now I'm laughing at the idea that this was the purpose behind the WW2-era fake teeth painted on fighter planes.

They really need a second study that paints big gnarly WW2 fighter teeth on cows to see what effect it has.

No big gnarly teeth, but re: the sibling comments, searching "dazzle cows" reveals https://journals.plos.org/plosone/article/figures?id=10.1371...

sadly not genuine dazzle camo but in the ballpark

That's neat and makes sense. I mean, aren't zebras basically "dazzle horses"?

I can't find the story now, but painting teeth on train doors reduces the number of people trying to jump through them as they're closing.

As I expected, the tigers adapted and there were other mixed results too

https://skeptics.stackexchange.com/questions/9179/does-weari...

IIRC, In Sundarban Delta (India/Bangladesh) people put on masks on the back of the head for similar reasons.

EDIT: Yeap, here's NYT article from 1989 https://www.nytimes.com/1989/09/05/science/face-masks-fool-t...

This reminds me of a Calvin and Hobbes comic where Calvin, having read about this practice, makes his own mask to protect himself from Hobbes' pouncing.

[1] https://www.gocomics.com/calvinandhobbes/1990/10/23

The outcome of Calvin's "experiment"

That's cool. The comic was about one year after the newspaper, so perhaps it got into the public consciousness during that period!

Apparently putting on a mask at the back of the head stopped working after a while https://books.google.com/books?id=zU7PmIjthpoC&pg=PA38#v=one...

It work on magpies. When they nest, Maggies "swoop" at people, dogs and such that get too close. In australia (where all birds are much bolder), people do the sunglasses trick.

My second day in Australia I had one swoop me about 5 times and then finally peck or claw my scalp and it was a bloody mess. I went into the trailer I was staying in and the bird perched on a branch and evil eyed me for 30 minutes. Those birds are gangster.

Later I saw kids waiting for the school bus with ice cream boxes on their head with two dots drawn on the back. Definitely not a fashion thing.

The locals got I good laugh from me getting pecked because they all know the tricks after the first warning swoop.

The magpies near me never swoop me, I've somehow made friends with them. They used to swoop my dog, until they saw me and my dog outside together, now they leave her alone. I love them though, they're friendly to other birds (but they have no tolerance for bullies), and they'll even chase off invasive species (Indian Myna birds). They are certainly the dons of my garden.

Could just be that you were new to the area. I walk everywhere so the magpies see me all year round, and by the time it's swooping season they know I'm not a threat. I only get swooped when I take a different path to normal and come across an unfamiliar family.

Yeah. Schoolkids do the ice cream container helmet. In groups, one usually walks backwards... like a troop of little commandos.

Even big cats use this technique to ward off big cats:

https://www.mindenpictures.com/cache/pcache2/00539194.jpg

I came to a different conclusion after watching footage of a family hunting together at night.

There is also a third very similar white dot on the tip of the tail which is very much more dynamic that the two fixed points on the ears. By moving the tail relative to the ears I would swear the ones in front could at least communicate their own intents to the ones behind them if not issue perfectly silent directives

Interesting theory, Tigers not know to hunt in packs, but you might be right thats it's a way to counter their own camouflage. Do you remember the footage.

It was a mother and juveniles, and it would have been decades ago. Maybe not exactly "Mutual of Omaha's Wild Kindom" but something similar.

[]https://en.wikipedia.org/wiki/Wild_Kingdom

I heard the exact same from a shark expert in the Great Barrier Reef. Rather than using a cage or anything we'd normally associate with shark diving, he puts a set of googly eyes on the back of his head and had been safely shark diving professionally for 2 decades.

Did you ever hear the tragedy of Vitaly Nikolayenko?

"He spent 33 years living with the brown bears (Ursus arctos) native to the Kamchatka peninsula (...) For over 20 years, Nikolayenko followed an enormous male he named Dobrynya, forming such an easy bond that the bear would often curl up to sleep just a few feet from him."

Eventually he died of a bear mauling.

Moral of the story: it works until it doesn't.

"True Stories of Survivorship Bias"

> Eventually he died of a bear mauling

Wow, same year and two months later than Timothy Treadwell, "Grizzly Man".

https://en.m.wikipedia.org/wiki/Timothy_Treadwell

Please don't tell the Discovery Channel about this. We'll be inundated by bear-related conspiracy theories. Or "Bear Week".

An unbearable week.

Did that bear maul him though?

I listen to Joe Rogan podcasts and he always mentions bears being very different than people think. He said they do all kinds of terrible things, even their own kind. (think how much food a large bear has to eat to stay alive)

To save someone the search: https://en.wikipedia.org/wiki/Vitaly_Nikolayenko

I don't think sharks have the same cognitive capacities as felines plus felines imply a lot of things about their prey when they do this like : there are only two eyes, facing the same direction, prey can only move in 2d etc... which are not true under water

Keep in mind the best shark experts have no idea how sharks reproduce.

I wouldn't call this "no idea"

https://en.wikipedia.org/wiki/Shark#Reproduction

Looks like 9 paragraphs to me. For comparison, we have MRI scans of human beings orgasming. Most of what we know about wild shark reproduction comes from observing a single population of nurse sharks living in the Dry Tortugas. That's a single population, of a single species, in one place on earth, at one time of year (summer). That's about it.

Why would animals recognize sunglasses as eyes?

Well, I still see Orca eyespots as eyes and I've known they're not for at least two decades now.

Deer and Elk have very dark eyes. https://tpwd.texas.gov/huntwild/wild/game_management/deer/im...

Some sunglasses (probably not all) kinda look like 2 dark circles with a gap between. If you can make the cat second guess it sometimes is all it takes to make it look for other game. They really don't like to eat us anyways from what I hear.

As a kid, to defend against magpie attacks we used to paint eyes on the back of the upturned ice-cream bucket we used as a helmet.

Worked as far as I could tell.

Sounds like survivorship bias to me /s

That is cool.

TIL :)

The eyes were painted on the cattle's butts.

Went looking for images, the article did not disappoint: https://www.nature.com/articles/s42003-020-01156-0/figures/1

Whoa!!

Went in expecting a couple of crude round spots for eyes

Got ACTUAL EYES with the whites, iris\pupil, darkened rims, even a suggestion of tear ducts

That is indeed terrifying. I can see how predators might have second thoughts

I wonder how it affects their fellow cattle, though. It must be weird to see your colleagues staring at you with their butts.

Wow, they don’t look very real at all.

Those predators must be feeling foolish

Anyone who’s read Babar the Elephant knows that trick :-)

https://www.telerama.fr/sites/tr_master/files/styles/simplec...

In India, Tigers attack and eat people on a regular basis. Villagers wear specially made face masks on the back of the head to confuse and dissuade attacks from the back.

There is evidence that prehistoric cats preyed on humans enough to have evolved specialized incisor teeth for crushing human sculls.

I’m assuming they’re a protected species or firearms of sufficient caliber are not prevalent in these villages?

They are:

* A protected endangered species

* Hard to track

* Better to not encounter than to fight

It's sort of like grizzlies in Northern America National Parks. Your ideal situation is you aren't encountering a half-ton apex predator so if you dissuade the encounter and you also avoid it, it's much better than attempting to perform Pavlovian training.

Attacks "on a regular basis" means a few dozen times per year in a country with hundreds of millions of people. Like pretty much all big predator attacks, the risk is really, really small; it's just so viscerally frightening that people get worked up about them.

I live in the US and hear far more concern about mountain lions than deer, even though people here are hundreds of times more likely to be killed by a deer. And do you know what helps control deer overpopulation? A healthy predator population.

High caliber firearms could be cost prohibitive, or simply illegal in that jurisdiction. Alternatively, firearms are only as useful as you are aware and capable of reacting...

Tigers tend to ambush their prey. You don't know you're under attack until its teeth are severing your jugular.

A handgun won't be of much use if you're jumped on from behind by a beast 3 times your weight and many times your strength.

If pouncing on villagers routinely resulted in catching a 12ga slug (buddy system when doing high risk things will do a pretty good job of guaranteeing that) then the tigers that live long enough to pass on their genes would be the ones that don't make a habit of pouncing on villagers.

It only takes a few generations for animals to become afraid of or lose their fear of humans. You see this in all sorts of species when hunting pressure is applied/removed.

I suspect you’d find that a single untrained human, even well-armed, isn’t always sufficient to kill a tiger.

So rather than avenge your buddy and improve the tiger gene pool, you’d get killed too.

For grizzly bear attacks, bear mace is more effective than guns. https://www.cbc.ca/news/technology/spray-more-effective-than...

You don't have to get them every time just often enough that they stop doing it It's about making it statically much riskier for the tigers to misbehave, not saving everyone.

Per https://en.wikipedia.org/wiki/Tiger_attack the majority who attack humans are infirm and desperate. Doubt taking them out of the gene pool would do any long-term good.

To get any firearm in India, you need to prove immediate danger from other humans, plus average basic daily income is $2 or something, so firearms are basically for rich people with enough connections.

I'm kind of thinking that this wouldn't scale. If some of the cattle have eye spots and others in the same area don't, the predators might be intimidated, or they might just say "that's weird, I'll hunt something else". But if all of the cattle have eye spots added, the cougars might just think "f it, I'm hungry".

My thoughts exactly. It'd be good if multiple separate herds could be tested, but that would get pretty expensive.

Then just paint large teeth under the eyes.

> Although no known contemporary mammals display anti-predator eyespots, the effects of eye patterns and gaze have been shown to modify behaviour in this Class including in humans, domestic and wild canids, and domestic cats.

Is there a reason mammals don't/haven't evolved this way? With cattle and other domestic animals I can understand that humans have been knowingly and unknowingly interfering with evolution so I suppose that isn't surprising. But why haven't deer or bunnies, for example, evolved to have white patches on their rear ends the way insects and birds have?

> But why haven't deer or bunnies, for example, evolved to have white patches on their rear ends

They have. Bunnies famously have distinct white tails that bob up and down as they run.

http://blogs.nature.com/news/2013/08/why-rabbits-have-white-...

And some deer have distinct white/dark patches on their backside:

https://krahnpix.files.wordpress.com/2012/09/t6c8813.jpg

https://i.imgur.com/6JZdQBz.jpg

The article conjectures that the function of these is to be a super-salient signal for a predator's visual system, so they attend to the wrong end of the prey in a chase. Maybe tracking the back end gives a degraded cue to the predators prey-motion-model. But the high-contrast patches are hard to ignore, like chaff for radar.

This is probably a different effect than false eyes have on cats, since cats sneak up on prey that aren't looking.

I'd guess possibly time? Insects have had a lot more generations filled with more frequent predation attempts and they've been doing it for longer. There is a lot more variation across insects than across mammals.

>Is there a reason mammals don't/haven't evolved this way?

Zebra is likely the closest adaptation. That's more of an optical illusion than eye logic.

I suspect it has to do with how fast big predators learn. If you put a fake snake in a fruit tree for example it takes about a month before the birds learn. Big apex predators learn even faster presumably. So that's just too fast on a evolution time scale.

Maybe there's not enough evolutionary pressure from predation to necessitate it. For deer and rabbits, they seem to be optimizing for speed and agility which makes other deterrence modes less necessary.

An eye pattern only deters ambush predators and the pattern could make them more vulnerable to other predators.

Sounds like the predators may eventually learn that they're fake:

"it is recommended that the technique be applied periodically, when predation rates are higher, also to avoid predator habituation."

With their bigger brains, perhaps cats and wolves can learn or visually identify discrepancies better than birds.

Fawns are covered in white spots, could that be why?

As for other animals, the RNG probably just didn't spin that way.

I suppose if they all had it, noone would be fooled anymore.

That argument would seem to apply to insects with eye markings as well, so can't be correct here.

First black and white spots to reduce mosquito bites, now artificial eyespots to reduce predation. By the end of decade, the cattles will look like mutants from a glance.

It's not bad though.

https://www.popsci.com/muscular-animals-babies-myostatin/

We already have mutant cattle, and dogs, and mice.

Zebra stripes reduced biting by horse-flies, indeed: https://journals.plos.org/plosone/article?id=10.1371/journal...

We are all mutants.

In fact, you are descendant from the original mutant(s)

I'm wondering if the same effect applies to humans. For example adding pictures of staring managers/bosses in offices, painting faces/eyes reduce certain behavior. A cool experiment would be paintings of police men reducing graffiti

Posters of eyes in cafeterias make it more likely for people to clean up after themselves https://www.sciencedirect.com/science/article/abs/pii/S10905...

Authoritarian regimes seem to be into portraits of the glorious leader "watching" everywhere.

A shop in England, 'poundland', which is quite a target for low value casual thieves, has a lifesize mural of a policeman in uniform at each store.

Don't know if it works, but they must at least think it does.

It does, the article mentions that painted eyes can deter bicycle theft, for example. There are more examples in the article.

Not exactly the same but that's a symbol in The Great Gatsby.

The eyes of Doctor T. J. Eckleburg are a pair of fading, bespectacled eyes painted on an old advertising billboard.

Everything is better with googly eyes on.

Interesting. If that's the case, I wonder why no large mammals evolved these patterns like for example, butterflies did.

It might be one of those things that fools predators for a few generations, and then starts having the opposite effect. Lions learn to look for the massive eyes, cos they're the tastiest bit of a cow...

Seagulls are real rascals where I live. The rude little buggers will grab your lunch right out of your hands, especially if you sit down, and become unobservant for a second. But here's a neat trick. Just look them in the eyes. This will make them really uneasy. An informal test is to put your lunch down on the ground while you stare into their hungry eyes. Usually they won't dare to grab it, or they'll stay insecure longer, before making an attempt. Some will just straight out fly off, once you start to give them the evil eye. And about that, another great way to get rid of birds, is to start walking around them like someone stalking them for dinner. They won't stay long if you give off predator vibes.

It works in stores to prevent shoplifting too.

And to keep people from trying to buy cigarettes while underage.

Eyes are magic. Pattern recognition that reaches down deep, maybe past the reptilian. Getting looked at can cause anxiety.

Maybe this adds to the appeal of masks.

>reaches down deep, maybe past the reptilian

it goes straight to the amygdala - the "lizard" or the "fight or flight" brain - see the brain scans in the link below for example. It is very short connection path from retina, something like right past the primary visual cortex, right beyond the last layers of simple/automatic pattern matching.

http://nautil.us/issue/39/sport/the-strange-brain-of-the-wor...

> Getting looked at can cause anxiety.

not surprisingly as it is usually the last thing one see before being attacked, so no wonder that amygdala starts to fire well before your conscious comes up with upper level decision whether there is any danger.

You when you're in the tool section of home depot and that little chime plus tv display beeps at you?

I'm uncertain if it prevents shoplifting, but it sure pisses off people like me who were browsing and prevents actual shopping.

Indeed, there are lots of stories about the effect of eye contact in human behavior, charisma and persuasion. Sam Harris has a few stories about this, and [writes a bit in this post](https://samharris.org/look-into-my-eyes/). Try to catch Osho, the guru in the video, blinking. He doesn't, he barely moves his eyelids 1/4 of the way down once a minute or so. It's fascinating.

Reminds me of the watching-eye effect:

https://en.wikipedia.org/wiki/Watching-eye_effect

The Eye of Sauron is a great motivator.

The really surprising thing about this is that it took so long for people to think of it.

People have been painting eyes on boats for millennia (for no practical reason we know about--maybe our ancestors had a problem now passed?) and wearing fake eyes on their own backsides for decades, but painting cattle never came up.

Even more novel is the idea, suggested in the conclusion, of using eyespots to protect depleted predator species against retribution by armed herdkeepers.

Wow, eyes on your butt saves your butt. I'm surprised that predators would not have figured this out and started ignoring them but apparently 100% survival rate. Definitely an improvement.

I wonder if you could make highly durable vinyl stick on eyes that would allow you to just apply them once a year. Put prism covers and you could make them blink as the cow moved like those cards that flip between two images based on the angle.

Interesting. From what I understand, an 'eye' pattern can be computed by taking variations of the standard map.

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

Cellular automata and reaction-diffusion is well observed in biology as morphogenesis.

I'm curious, is there a color-specific advantage to monochromatic patterns that can be explained by theory?

I was amused by a podcast I listened to where some guy delivered donuts and a pay on the honor system coffee can. He found that drawing a pair of obviously fake eyes on the collection box significantly increased the amount of money he received per donut.

So apparently even humans are sensitive to obviously fake eyes.

The reduction in predation by large carnivores masks the fact that african large carnivores are being systematically wipped.

And, well... most large carnivores hunt at night. I think that white eyespots just would make preys more visible in the dusk and dawn, when the "90%" of predation events happen.

I remember seeing a documentary where they showed fish having "eye" spots on their rear: https://en.wikipedia.org/wiki/Foureye_butterflyfish. I found it such a hack.

What's more crazy about this is that the 25 day survival rate for these cattle is only 98%.

I've heard years ago that wearing googly eyes on the back of your helmet is a good way to cut the chance of a cougar attack on a bike. Just like you I think I'll go grab some today!

I wonder if googly eyes on the back of a bike helmet would reduce the chance that you get rear-ended by a car as well.

“Should animals have more eyes? Why don't they? Onion Science Editor Raef Gillis wonders.” https://www.youtube.com/watch?v=yUOAZisYQjM

Surely predators will eventually learn that eyes on the back of animals are to be ignored?

> ... eyes on the back of animals ...

Q: Cubs! If you attack a horned prey animal from the front, what will happen to you?

A: You will be gored.

Q: Cubs! How do we know which end of the animal is the back?

A: The back end has no eyes.

Q: Cubs! What happens to us if we do not pay attention to prey eyes?

A: We will not reproduce.

The back ends tend to be a bit kick-y.

Is that a quote?

Remember that every adaptation comes with a tradeoff. This adaptation may require more complex brains which cost space and/or energy.

Which side is the back?

kinda of like avoiding any opportunist predator spammer, hacker, advertising ... If you do anything chances are really good they will just move one to something that is not.

"Eventually" may take a long time.

I can honestly say that this is the most unusual article I have ever seen on Hacker News.

It’s interesting to relate this to adversarial attacks on computer vision systems. Something “low-tech” like this that works on mammal predators might protect against predator drones one day.

Looks like the cross marked cattle faired better than unmarked as well (though not as well as those with false eyes). I wonder the significance of that.

Maybe painting a gaping artificial mouth snarling with long pointy fangs on a cow's butt would help too?

Sounds like adversarial patches

Won't predators learn eventually not to get fooled by that?

Do you mean at an evolutionary time scale or within their life times?

I think both would occur, as long as the particular predator has a sophisticated enough brain to learn this.

On an evolutionary timescale, there would probably be an arms race of sorts leading to an equilibrium of predator/prey phenotypes.

Depends. If there isn't a strong enough selection pressure (there is plenty of wild prey, they only rarely attack cattle) then they wouldn't learn to ignore the eyespots for many generations.

These are basically adversarial techniques to take advantage of weaknesses in a biological neural net. Love it.

Even better: Eyespots with built in lasers.

I bet if you painted a picture of Jimmy Wales (Wikipedia founder) on the cow, not only would the carnivores not eat the cows, they would probably bring the cows food.

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