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Robotics Hardware Idle Science

Robotic Squirrels Battle It Out With Rattlesnakes 125

Posted by samzenpus
from the I-for-one-welcome-our-new-metal-sciuridae-overlords dept.
Hugh Pickens writes "Alasdair Wilkins writes that when a squirrel encounters a rattlesnake in the wild, it does something very peculiar to survive its brush with the predator — something is so peculiar that scientists are building robotic squirrels just to try to understand the behavior. A live squirrel does two things when it sees a rattlesnake. It starts moving its tail in a flagging motion and actually heats up the temperature of its tail. Because rattlesnakes can see in the infrared wavelengths, they should be able to see both the tail move and heat up. The question is which of these two signals is important and just what message it's supposed to send to the rattlesnake. To that end, engineers at UC Davis have built robosquirrels, which allow the biologists to simulate the two squirrel behaviors one a time and the research so far suggests it's the heated tail, not the flagging motion, that the snake responds to, making it one of the first known examples of infrared communication between two distinct species. 'Snakes will rarely strike at a flagging adult squirrel — and if they do they almost always miss,' says Rulon Clark, assistant professor of biology at San Diego State University and an expert on snake behavior. 'In some cases, it seems the rattlesnakes just decide it's best to cut their losses after dealing with these confusing critters,' adds Wilkins, 'as sometimes the snakes just leave the area completely after encountering these flagging, tail-heating squirrels.'"
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Robotic Squirrels Battle It Out With Rattlesnakes

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  • by ColdWetDog (752185) on Thursday April 05, 2012 @03:21AM (#39582219) Homepage

    Perhaps these robocritters can deal with the plague of our snake-in-the-grass politicians.

    I, for one, welcome our new hot tailed rodent overlords.

    • I can see a movie starring the likes of Steven Seagal/Bruce Willis/Sylvester Stallone/Arnold Schwarzenegger being pitched to Hollywood execs right now.

      God damn you, Michael Bay.
      • by geekmux (1040042)

        I can see a movie starring the likes of Steven Seagal/Bruce Willis/Sylvester Stallone/Arnold Schwarzenegger being pitched to Hollywood execs right now...

        (overheard near Sly Stallone talking to someone on his cell phone)...

        "What?!? What do you mean the script was leaked for Expendables 3?!? How the fuck do they know about the robot squirrels!?! Dammit, heads are gonna roll!"

      • ...starring the likes of Steven Seagal/Bruce Willis/Sylvester Stallone/Arnold Schwarzenegger

        Geriatric brigade vs. Squirrels? My money is on the tree rats.

  • The question is which of these two signals is important and just what message it's supposed to send to the rattlesnake.

    The most important message: Dinner is served!

  • by terminalhype (971547) on Thursday April 05, 2012 @03:25AM (#39582231)
    They also need to make a moose...
  • by nooneelsesname (2368368) on Thursday April 05, 2012 @03:33AM (#39582253)
    ... the tail wagging evolved to attract strikes from snake species that target movement, while the "heating tail" evolved to attract strikes from species that target heat (like rattlers). Maybe in the daylight it will be the wagging that saves the squirrel. Perhaps, if the waggging has no effect on squirrel survival, it's a leftover from an earlier evolutionary stage, where the snakes didn't have the infrared targetting capability.
    • by Anonymous Coward on Thursday April 05, 2012 @03:36AM (#39582267)

      Or it could be that the tail wagging helps get the blood flowing through the tail and causes the tail muscles to generate heat through use...

      • by Captain Hook (923766) on Thursday April 05, 2012 @04:20AM (#39582395)
        The article also said that the snake almost never struck at the flagging tail and if it did it normally misses.

        That suggests the tail is being heated up to make it a more inviting target and the movement is there to ensure that the snake never get a chance to actually strike (which presumably would still kill the squirrel unless it can cast off the tail/shutdown all blood flow before the poison makes its way into the core organs). I assume the tail can be moved far more quickly and erratically than the squirrels main body mass.

        It sounds to me more like a matador using a cloak as a target for the bull. Something to draw the attention in a way which encourages an attack (or at least preparation for an attack) at the point which has least chance of causing damage.
        • by hairyfeet (841228) <bassbeast1968 AT gmail DOT com> on Thursday April 05, 2012 @05:16AM (#39582511) Journal

          Well you have to figure in the fluff of the tail which means most strikes unless the snake hits dead solid perfect all he is gonna get is a mouth full of fur. if you have ever seen a squirrel's tail up close it really is just this little thin string, much like a rat's tail, and it only looks big because of the way the fur poofs out.

          So it makes sense, give the snake a fast moving target that severely cuts down his chances of actually getting a strike and of course once it has struck the squirrel has time to scamper off. Just another case of the classic predator and prey evolution at work.

          • by TheCarp (96830)

            Thats what I was thinking. Also.... what kind of a bite is it going to get on a tail? Tails are bony and thin. A good strike might break the tail right off.... and if it didn't, there just isn't much space to leave poison in.

            In fact, some poisonous snakes have been shown to not use their fangs in some situations, like defensive striking. The studies I have seen in the past theorised that the snake was protecting its fangs. Think what could happen if they got a good chomp, sinking their fangs straight on int

            • by datavirtue (1104259) on Thursday April 05, 2012 @08:54AM (#39583497)

              You've obviously never been bitten by a snake. They are real pussies. There isn't much force to the bite and their fangs (most of them) are like hollow tubes. I emerged from my apartment one day (some years ago) to find that my neighbor (a real brainiac) had a large brown snake pinned down under his foot. The head and about 8inches was loose and in full honey badger mode--it was pissed. Nonetheless, I decided it might be a good idea to grab the head of the snake whilst he had it pinned down. Of course, it struck at me in an attempt to sink its fangs into the plump part of my hand between the index finger and thumb (bible bump?). Upon screaming like a little girl, and yanking my hand away at lightning speed, the snake's fangs broke off after having penetrated my skin ever so slightly. I learned several things from that incident.

              • Re: (Score:3, Interesting)

                by Anonymous Coward

                > I learned several things from that incident.

                1. don't grab snake with bare hands?
                2. don't denigrate your neighbor who was smart enough not to try to grab snake with bare hands?
                3. ?

                • by vonhammer (992352)

                  Hmm, I'm guessing:

                  3. Always scream like a girl when something bites your bible bump.

                • how did he denigrate his neighbor? - being a brainiac is a good thing, no? I didnt take it as sarcastic because the point of the post was to denigrate the author (humorously)
          • by fredrated (639554)

            Except that the heat, which a rattlesnake perceives, would not be in the fluff but in the body of the tail.

            • by hairyfeet (841228)
              Heat radiates very quickly through fur, which is why you don't see squirrels dropping dead in the summer. I'm sure if you looked at the thermal image of the squirrels tail it looks like a bed red blob with the heat being spread pretty quickly to the fur.
            • The actual flesh of a squirrel's tail is going to be roughly a quarter inch wide. If the snake's strike were perfectly on center, each fang would miss the tail, one fang on each side. The squirrel is much more likely to get away than if the snake strikes the squirrel's body.
        • by TubeSteak (669689)

          That suggests the tail is being heated up to make it a more inviting target and the movement is there to ensure that the snake never get a chance to actually strike (which presumably would still kill the squirrel unless it can cast off the tail/shutdown all blood flow before the poison makes its way into the core organs).

          Most animals have a much higher tolerance (by bodyweight) for venom than us puny humans do.
          The really interesting thing is that studies show this tolerance varies between populations of the same animal.
          Squirrels that live in poisonous snake country are naturally selected for tolerance.

          Other animals (like badgers or humans) can gain tolerance over time as a result of repeated exposure to venom.

    • Re: (Score:2, Funny)

      by Anonymous Coward

      Yep, a countermeasure. Obviously squirrels couldn't evolve an IR flare dispenser, so this is the next best thing.

      Not much to a squirrel's tail other than fluff to bite on anyways, so the odds of the snake striking anything vital are pretty slim.

      • by X0563511 (793323)

        Indeed. I wouldn't call this a communication method, but an active defense measure. If you insist on calling this a form of communication, then I suggest "biting" and such be as well.

  • by perpenso (1613749) on Thursday April 05, 2012 @03:33AM (#39582257)

    A live squirrel does two things when it sees a rattlesnake. It starts moving its tail in a flagging motion and actually heats up the temperature of its tail. Because rattlesnakes can see in the infrared wavelengths, they should be able to see both the tail move and heat up. The question is which of these two signals is important and just what message it's supposed to send to the rattlesnake.

    Its not sending a messages. Its presenting a decoy target.

    • by Anonymous Coward

      A live squirrel does two things when it sees a rattlesnake. It starts moving its tail in a flagging motion and actually heats up the temperature of its tail. Because rattlesnakes can see in the infrared wavelengths, they should be able to see both the tail move and heat up. The question is which of these two signals is important and just what message it's supposed to send to the rattlesnake.

      Its not sending a messages. Its presenting a decoy target.

      It is a secret message, you're supposed to decode it with the a snake decoder ring. I used my pet snake's ring and it says: Be sure to drink your Ovaltine.

    • by Mr. Underbridge (666784) on Thursday April 05, 2012 @04:08AM (#39582363)

      Its not sending a messages. Its presenting a decoy target.

      The message is "Look, over here! No, over here! Hah, made you miss! You suck! That's right, slither away with your tail between your legs! Hahahaha, you don't have legs! Loser!"

      It's just that at normal speed instead of squirrel speed, you can't hear the trash talk that accompanies the flagging.

      • Its not sending a messages. Its presenting a decoy target.

        The message is "Look, over here! No, over here! Hah, made you miss! You suck! That's right, slither away with your tail between your legs! Hahahaha, you don't have legs! Loser!"

        It's just that at normal speed instead of squirrel speed, you can't hear the trash talk that accompanies the flagging.

        So squirrels are the world's first trolls? I can dig it

      • I think you just wrote a Randall script. Good job.

    • by Anonymous Coward

      Predator/prey relationships are fascinating biology, psychology, physics, chemistry, optics, acoustics, and many soft and hard sciences in the mix. Add the drama and sex inherent to the systems, and you have a recipe for endless fun and entertainment. A lot applies to human relationshps, too.

      Check out Wolfgang Wickler's "mimicry" book for a lot of fascinating study and beautiful illustrations to learn a lot about the the biological world and even some lessons about human mating. The idea that a deadlier poi

    • It may be a little more complicated. Many years ago in a wildland area in southern California I came on half a dozen or so ground squirrels who had discovered a rattlesnake and were driving it from their feeding area. The snake would attempt to move away and then two or three of the smaller squirrels would dash up and nip it (counting coup, I guess). The snake would then whip around and attempt a short strike that would miss, coil, wait a bit and then attempt to flee again. This repeated itself for some

      • by X0563511 (793323)

        Usually a snake's vision is really only adequate to detect motion - so the higher temperature spoofs the thermal detection, and the shaking spoofs the visual. I'd say it's more that than anything else - squirrels aren't exactly mute and do a good job of shouting out about danger... so the use of the tail to signal would be secondary if anything.

    • by Fned (43219)

      Its not sending a messages. Its presenting a decoy target.

      Presenting a decoy target IS sending messages. Unless you can think of a way to "present a decoy target" without sending specific, tailored information to the incoming threat's sensors...

  • This is one of the strangest things I've seen on Slashdot. Heated tail countermeasure causes snakes to give up. W T F.
  • easy (Score:5, Interesting)

    by dutchwhizzman (817898) on Thursday April 05, 2012 @04:06AM (#39582355)
    I have had pet snakes for the last 10 years of various species, some with IR receptors.

    Big warmed things tend to trigger the "too big to eat" response in snakes. That is, as long as they are moving. Stationary dead but still warm prey, may be looked upon as "luck, I found myself a free meal".

    Most poisonous snakes tend to either not inject venom at all, or tone down the dose considerably when attacking as a defensive movement. Hence, even if the snake seems to miss, it might actually have hit and bitten, but no big damage is done. Making yourself too big to eat is an advantage even if it comes to a fight for the squirrel. For the snake, it makes no sense to waste valuable poison on something you can't eat, so just a warning dose will be more economical.

    The squirrel can counter-attack and bite the snake behind the head if it attacks the big moving warm thing just next to the tail. There is plenty of evidence on youtube they do just that.

    It will take quite some robotic squirrels before you can statistically prove these things, but I'm fairly certain most of these logical assumptions will be backed up by numbers.
    • The squirrel can counter-attack and bite the snake behind the head if it attacks the big moving warm thing just next to the tail. There is plenty of evidence on youtube they do just that.

      So you're saying that a squirrel is really a small mongoose?

      (Eyes furry rodent hanging out at the bird feeder with a bit more respect.)

      • Except that squirrels eat nuts and mongoose eat snakes. Otherwise spot on.

      • (Eyes furry rodent hanging out at the bird feeder with a bit more respect.)

        I honestly think that the squirrels around my house are smarter than my dogs (of course that's not saying much). And there are sooooo many crazy squirrel stories I could tell...

        Suffice to say, once one of the squirrels stole my coffee, I had very little trouble with choosing my subject for an ethology project.

    • by Formalin (1945560)

      The only snake I have with thermal receptors is a little python.

      He usually has pretty good aim, even in the dark. However, after he squeezes the prey for a few minutes... it often seems like it's too cold, and he has a very hard time finding the rodent. My heat-pit-less snakes never have this problem - maybe their smell is considerably better, to compensate? Or their physical (touch) heat sensing is better. Hmm.

      Not sure if that's common, or if he's just extra special, though...

      A python has a bunch of heat p

    • by symes (835608)

      I'm glad a fellow snake owner commented on this - my first reaction to the story was why don't they just go chat with some people who feed snakes regularly rather than rush off an build robotic squirrels. Obviously building robotic things are a priority it just seems there's probably more interesting robotic things to build. Anyhow, as far as I know, rattle snakes eyesight is far from their strongest sense and it would, in general, be odd for any land-based snake to rely on eyesight very much at all. Mine r

      • by X0563511 (793323)

        Because statements from snake owners are not scientific evidence. Sure, they can be used to help build the hypothesis, but not to prove/disprove it (which is what the robots were for).

        You should go bone up on the scientific method, seems you forgot some of it :P

        • by symes (835608)

          Simulation whether with robots or simple models have never been as useful as they might be - a small change to a parameter can yield very unstable results. No problem with drawing in expertise to refine hypotheses, whether they are selling snake oil or not

    • You're the Adam Smith of the snake world.

    • Nitpick mode on:

      It's not 'poisonous', it's 'venomous'

    • by X0563511 (793323)

      Lets also not forget that most snake's vision is only acute enough to detect motion effectively - there are exceptions of course. So the tale shaking couples with the heat to draw the snake's attention away from the body with two senses.

  • by julesh (229690) on Thursday April 05, 2012 @04:07AM (#39582357)

    Article title sounds like one of his games.

  • by Anonymous Coward on Thursday April 05, 2012 @04:08AM (#39582365)

    Interestingly, it turns out that the squirrels (North American ground squirrels, in this case) are even cleverer than that, as the same team at UC Davis have previously shown. When confronted with a snake with infrared sensing organs (i.e. a pit viper, of which rattlesnakes are one variety), they engorge their tails with blood to send that infrared decoy signal. However, when they meet up with other kinds of non-infrared sensitive snakes (e.g. gopher snakes), they only flag with their tails; they don't use the infrared trick as well:

    Squirrels wield a hot secret weapon [newscientist.com]

    Why the difference? Presumably because it costs energy to send blood to your tail, where it then cools as it sends out its infrared signal. Thus, in evolutionary terms, it only makes sense to incur that cost if it has an advantage. Since gopher snakes can't sense in the infrared, why bother?

    Of course, with respect to the current findings, it suggests that both flagging and infrared decoy measures are important to a ground squirrel, not just the infrared part. Otherwise, why would they bother flagging? Perhaps just because they have fun annoying snakes ...

    And while the snakes might come off as just dumb reptiles in this story, let's not forget that those infrared sensing organs are pretty amazing as well. They have limited spatial resolution, but extraordinary temperature resolution, down to 0.001K. Indeed, once upon a time as a PhD student, I calculated that if you strapped a rattlesnake to the back of a 4 metre infrared telescope (!), it could detect the signal from Eta Carinae, one of the brightest infrared stars in the sky. Strap on thousands of rattlesnakes and count when each one rattled its tail, and you could take images :-)

    • Bugger: sorry, forgot to log in before posting the previous comment: it was from me, honest ... :-)
      • Has anyone given thought to attaching rattlesnakes to sharks to assist with laser targeting? It would be a wonderfully evil contraption.

    • by Anonymous Coward

      Strap on thousands of rattlesnakes and count when each one rattled its tail, and you could take images :-)

      It's called the Snake Kicking Array, they're still trying to figure out where to build it. Last I heard they wanted to build it in some desert in Australia or South Africa just in case the snakes escape.

    • by itmo (605864)
      They should read up on heat seeking missile seeker heads and how to jam them. It seems to me Sidewinders have more commonalities with Sidewinders than previously thought. Basically it could be that the tail acts like a flare does or that it acts like an IRCM pulsing jammer does. ie. it either attracts the snake to strike at the center of the heat signature, which in this case is probably between the tail and body == air, or causes the snake to get confused about where to aim it's strike if the infrared sigh
      • by itmo (605864)
        (disclaimer:I don't know much about snake heat-sensor anatomy) It seems to me that (according to wikipedia) , the organs are adaptive and register relative temperature and calibrate themselves with a certain latency (50-150ms). So it might be that the squirrels are basically jamming the snake's heat detectors by moving the heat source at a certain hertz.
        • by itmo (605864) on Thursday April 05, 2012 @06:14AM (#39582683) Homepage
          wikipedia: "The nerve fibers in the pit organ are constantly firing at a very low rate. Objects that are within a neutral temperature range do not change the rate of firing; the neutral range is determined by the average thermal radiation of all objects in the receptive field of the organ. The thermal radiation above a given threshold causes an increase in the temperature of the nerve fiber, resulting in stimulation of the nerve and subsequent firing, with increased temperature resulting in increased firing rate.[9] The sensitivity of the nerve fibers is estimated to be >0.001 C.[10]" So assuming I fill up your sight picture with a moving heat source which will cause the average temperature of the whole area to rise. Will that not mess up your contrast by making your signal show up less from the average? So by filling up the field of visiion with a heated moving tail, they are actually making their body show up less. So what the snake sees is a confusing , low contrast blob of heat.
          • by mbkennel (97636)

            not only that, but the blob of heat looks much bigger, as in "maybe this is actually a coyote and too big to eat" size.

            By the way, the infrared jammer of heat-seeking missiles doesn't quite work like that. The missiles (older designs) have some kind of rotating "optical chopper" used to increase the signal to noise ratio of a point target and help with angular control. The IR detectors themselves were only one pixel or so. The jammer is designed with special knowledge (ahem) of the particular control syste

    • by splutty (43475)

      And then the bar closed..

    • Isn't it easier to "send blood flow" to a moving limb? Try warming up your hands or feet on a cold day without flexing them: it really does help to move them. Also, just thinking about the body movements, I think an animal that already has some motion going can dodge or jump more easily than one standing completely still. That tail gives some leverage to twist or turn the _rest_ of the body, doesn't it?

      Did you publish the rattlesnake IR astronomy theory? That kind of analysis is one of the delights of scien

    • by Anonymous Coward

      How does the squirrel know which species of snakes use IR and which don't?

    • by X0563511 (793323)

      It could be that pumping extra blood into the decoy is an extra risk - eg, a successful strike from the snake would result in more blood loss.

      • by BluBrick (1924)
        Wait, what? A successful strike from the snake would result in a bit more than mere blood loss. These are venomous snakes, remember. A bite which would make a big animal like a human sick for a few days will kill a little squirrel in pretty short order.
        • by X0563511 (793323)

          Snakes generally do not put much, if at all, venom into a defensive strike against something it thinks is too big to eat (which is what the heated tail tricks them into thinking). Humans are stupid and clumsy so they usually get bit several times in an encounter.

          At least these are my understandings.

  • Unusual (Score:4, Funny)

    by LittleBigScript (618162) on Thursday April 05, 2012 @04:16AM (#39582387) Homepage Journal

    I find it odd that a snake in the grass wouldn't stike out at some hot tail.

    • by Rhacman (1528815)
      It's intimidating, some tail is just too hot to be had. It plays against the snake's feelings of inadequacy. The moral of the story is that you've just got to keep slithering out of your hole in the ground every morning, keep searching for that hot tail, and don't be afraid to strike when you find it!
  • I'm guessing it's unlikely, but I was wondering if this trait can also be found in the Red Squirrel native to the UK - no rattle snake prey here, so I'm guessing this trait was never needed. Either that, or the Red's were so good at it, the rattle snakes were wiped out by starvation ;)
    • The squirrels in question aren't the grey or red ones that run around in trees; they're ground squirrels, so things like marmots and prairie dogs at the big end and chipmunks at the small end.

      I don't think regular grey tree squirrels are from the same genus. And I'm not 100% sure that all ground squirrels do this; the classic example of an infrared light sabre wielding species is the California ground squirrel.

      • by hannza (2480742)

        Yeah, the species studied is Spermophilus beecheyi, the California Ground Squirrel.
        The grey squirrels in the US are Sciurus griseus (the Western Grey squirrel), Sciurus arizonensis (Arizona grey) and Sciurus carolinensis (the Eastern Grey squirrel), and the 'red' (more brownish) squirrels in the US are Sciurus niger (the fox squirrel, pretty much all over North America) and Tamiasciurus hudsonicus (red squirrel). The red squirrels in the UK are most likely Sciurus vulgaris (the Eurasian red squirrel) and t

  • Oh, come on. This is just a form of cockfighting thinly shrouded in a veil of "scientific experiment." The scientists just really want to watch and bet on the fights. Wait until the PETA folks hear about this!

    It there a PETR for robots, cruelly forced into combat with vicious snakes, to entertain bloodthirsty humans?

  • When you've confirmed that IR link has been established, hit CTRL+P.
    You still had to walk right over there.

    • by uncanny (954868)
      so.... to connect this to the topic of the article, um... when an Airlink is confronted with a rattlesnake, its defense mechanism is to cause you to walk over to it, thus causing excess heat to buildup and scare away the snake, or at least get you bitten instead of the airlink?
      that's quite a leap you made, but i guess it makes sense!
  • by Anonymous Coward

    Sitting at work I read the subject "Robotic Squirrels Battle It Out With Rattlesnakes". My mind starts to race with cool images of robotic squirrels trashing some serious bad ass rattle snakes.

    My hand shaking in anticipation I decide just this once to open up a post on slashdot when I should be working. Looking around I see the mindless drones tapping on their keyboards and I think to myself - after I read this the world will some how be different.

    I then open the article and find that it's a robot squirrel

  • While this topic makes for some fun and entertaining reading, I cannot help but wonder "who pays for this crap?" I recognize that there is value in humans exploring and understanding our world as well as the general pursuit of knowledge in all forms. However, I have seen a lot of very important research that fails to receive funding because there are simply higher priorities and so I wonder how something like this managed to get above the line where someone was willing to put time and money into it. Maybe t

    • by X0563511 (793323)

      Newsflash: not everyone shares the same priorities.

      • by iamwahoo2 (594922)

        You are very correct. a lot of personal donations fund a lot of research targeted at those individuals personal priorities, but this is National Science Foundation money which usually means there is some sort of public interest being served by the research and since there are so many areas that rank high on the public interest for funding, the goal is usually to put the money towards those areas that will have the greatest impact for the public. I am just struggling to see great value in this research. Are

  • Their life is already bad enough...

    "Now I lay me down to bed
    Darkness won't engulf my head
    I can see by infrared
    How I hate the night"

    --Marvin

    • by markian (745705)

      It's, "Now the world has gone to bed"

      You were thinking of the first verse,

      "Now I lay me down to sleep
      Try to count electric sheep
      Sweet dream wishes you can keep
      How I hate the night"

  • by 2fuf (993808) on Thursday April 05, 2012 @08:39AM (#39583383)

    definitely ig Nobel worthy

  • Ah, good. Some good old fashioned nightmare fuel.

  • I'm sorry, but what important problem are they trying to solve with this "research"?

  • If you put rocket launchers on the squirrel? We must test it... FOR SCIENCE!
  • "research so far suggests it's the heated tail, not the flagging motion"

    The rattlesnake is a pit viper. IR is it's targeting flag. Holy shit, every herpetologist in the damned world knows this. Hell, every biologist in the world. Every fucking kid who likes snakes.

    "Research" like this is only proving the known with an empirical test. Worthwhile in the textbook sense that some other animal has evolved a mechanism to defeat it, worthless as news concerning the snake.
  • The fact is,ADULT California ground squirrels are largely immune to rattlesnake venom. What the squirrel is doing is flagging to attract attention away from their PUPS which have not yet developed immunity.
  • Rattlesnakes have poor eyesight. A squirrels tail heating up has little actual skin/bone/tissue. A snake striking at the tail (which the squirrel is enticing the snake to bite with the movement) is a hell of a lot smaller target than the squirrels body. So a snake that expends it's venom in a missed strike is worthless.

    Meerkats do something similar except that they will form a line and undulate opposing each other, you up, neighbor down. This tends to confuse cobras and in the end the snakes look for an ea
  • The tail heats up so that it's more obvious to the snake than the body, while it moves rapidly to reduce the chance of the fangs actually stabbing the flesh of the tail.

It is not for me to attempt to fathom the inscrutable workings of Providence. -- The Earl of Birkenhead

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