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Comment by nate_meurer | Hacker News Reader

I have four dogs, and I watch them poop every day. For some reason they have to slowly turn lots of circles before they're satisfied they have the best pooping position, and if the sun is out, they almost always settle on a position where they're not facing directly into the sun.

Makes sense from a practical viewpoint. You're more vulnerable to attack when you're pooping out in the open, and even moreso if the sun is right in your eyes.

To the extent that more pooping is done near the middle of the day, north-south pooping orientation would naturally dominate. No need for a sixth "compass" sense.

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> Makes sense from a practical viewpoint. You're more vulnerable [..] and even moreso if the sun is right in your eyes.

"Dogs, like everyone, don't like the sun in their eyes." would be enough of an explanation for me. Predators even don't like the sun in their eyes, that's why they attack with sun behind them, if they can. Wouldn't make much sense for the dog to turn it's back in the most likely direction a predator is going to attack.

If predators attack with the sun behind them then shouldn’t dogs look into the sun to protect themselves?

Dogs look to their pack for protection while doing their business. If your dog stares at you while he's pooping, this is why. It's also why he might follow you into the bathroom... to keep you safe while you do your business.

But dogs are descended from wolves, which I think are apex predators, and were domesticated by humans, another apex predator.

Dogs are predators. We've domesticated a lot of that out of them, sure, but they've got the eyes facing forward and carnivore digestive tract. What would be higher to a wild dog or wolf in the wild?

Actually dogs & wolves have jaws and digestive tracts consistent with omnivores which are significantly longer than that of carnivores.

Correct. They can digest quite a bit of plant matter.

Cats, on the other hand, are carnivores.

I had a cat who liked tomato. It was weird.

Anything can be explained away depending on which variables you take into account.

Some people like heated toilet seats. Maybe most dogs like some warm sunhine on their behinds while pooping.

Or maybe they want to face upwind for other reasons.

> Predators even don't like the sun in their eyes, that's why they attack with sun behind them, if they can.

While I have no doubt that predators don't like having the sun in their eyes, they would obviously still prefer to attack with the sun behind them even if they didn't care. It's very advantageous, because the prey doesn't like having the sun in its eyes.

Attacking with the sun behind you is to prey with eyes what attacking from downwind is to prey with noses.

> and if the sun is out, they almost always settle on a position where they're not facing directly into the sun.

The (linked) article says:

> (...) This calls for necessity to test whether the dog alignment is not actually influenced primarily by time of the day and most probably by position of the sun on the sky. We can, however, exclude this alternative. (...)

This has been discussed elsewhere in this thread. See my earlier comments for a rebuttal. Others like jwmerrill, dodobirdlord, MrEldritch, etc. have also made insightful remarks.

This is also why dogs stare directly into your eyes as they poop. They're vulnerable, and you're their lookout.

Might also be why they come into the bathroom or wait by the door when you're doing your business.

That looks like a good explanation for all that monitoring borderline stalking going on in that specific room! I never thought of it, from now on I'll thank my dog for their service!

I’d ask for a source, but I choose for this to be true.

Sounds easy to test in the Southern Hemisphere. The sun being north rather than south is one of the things that threw me off when I first went to Australia.

> north-south pooping orientation would naturally dominate. No need for a sixth "compass" sense.

What if it's both? Compass sense helps align them north/south for better vantage even when the clouds obscure the sun at the start of defecation/urination.

I skimmed the study and did not see anything regarding having controlled for day/night/cloud cover.

That's a hypothesis that can be checked. Go over the data and splice it by time of day, or rather position of the sun given the location/time/day of year. Then you should see a much higher correlation when the suns out than when pooping at night.

from the paper -- https://frontiersinzoology.biomedcentral.com/track/pdf/10.11...

Typically, the daily declination comprises westwardshifts in the morning and eastward-shifts in the afternoon, while the magnetic field is rather stable at night [21,22]. This calls for necessity to test whether the dog alignment is not actually influenced primarily by time of the day and most probably by position of the sun on the sky. We can, however, exclude this alternative. First, days when the magnetic field parameters change erratically and unpredictably (i.e., magnetic storms) are quite frequent. These changes have been well studied by others and are described in the literature (cf. [21,22] for reviews). Second, the data collection was not biased to either morning or afternoon (Table 8). Third, periods of sampling under conditions of quiet magnetic field were rather evenly distributed in the course of the day. Fourth, and most importantly, alignment during excreting was apparent under conditions of quiet magnet field, irrespective of the time of day or month. Time of day per se was not a reliable predictor of expression of alignment (Figure 2, Tables 3, 9). Fifth, generally, there are on average 1,450 sunshine hours per year at maximum in the Czech Republic and in Germany, on localities where measurements were done. Even if we would assume that these sunshine hours were evenly distributed over the daylight period and the year (as our observations were), there would only be a probability of 33% that the observation was made when the sun was visible. Hence, with high probability (67%) most walks during the daylight period were made when it was cloudy.

Last but not least, the argument that the dogs might orient with regard to sun position so that they turn with their back to the sun in order to avoid dazzling by sunshine during such a sensitive and vulnerable act as excretion can be questioned. This argument is not plausible for urine marking, which is a brief act. We doubt that a dog that cares of not being attacked would always make sure to be turned away from the sun. The dog will likely look in that direction from where danger can most probably be expected - and this is for sure not always the direction away from the sun. In contrast to a human, the dog is relying also on its nose and its ears (in some breeds even more than on its eyes) when monitoring its surroundings - so we may expect that the dog heads with its nose and pinnae against the wind or in the direction of interest. Directing the pinnae and the nose may take priority over eyes. One can also often observe that dogs (especially during defecation) align in a certain direction, which is actually a different one from the direction of interest and they turn their head then in that other direction. Also we have to take into account that dogs are smaller than humans, they look at a different angle over the horizon and even in situations when we are dazzled, they might be not. Quite important: note also that the preference is axial - there are many cases when the dog actually looks southwards. There is no evidence for shift of the alignment axis during the day.

that is.. a stretch. so they didnt actually look at sunlight hours they simply assumed the probability from the distribution of the data?? both hypotheses are plausible (sunlight vs magnetic fields) but this reads like data fitting rather than treating each possibility equally blind. where was it published?

Yes, I read the whole thing when it came out years ago. I remain thoroughly unconvinced. Back when this study came out, pop-sci magazines and websites reported it uncritically. But it was also a much less cynical time, before the reproducibility crisis really took hold.

Aside from the blatant and unapologetic p-hacking, there are some other flaws of data gathering and analysis that make their conclusions dubious. For example, note that your first paragraph above seems to admit that the actual presence of direct sunlight was not recorded in the raw data. They only figure in a statistical inference based on average hours of sun in a locale.

Rather than copy-pasting myself, here's a better critique from 2014 with good explanations of the study's problems:

http://skeptvet.com/Blog/2014/01/do-dogs-line-themselves-up-...

Maybe you should have started with that, rather than anecdotal evidence. I agree as a case study of potential p-hacking, it's pretty illustrative. Not sure if it's failed p-hacking though. For example -

High school students, but did make it into a journal ..

Dogs excreted with the body aligned along the North–South axis, but when exposed to small bar magnets, significantly changed their directional positions. The study suggests that dogs are able to recognize MF.

Additional value of this research is that the data were collected by local high school students, which required collaboration with teachers and their parents. We think that this idea has great potential and can be developed at a global scale and to become a citizen-science project involving other high school pupils and their families.

https://www.sciencedirect.com/science/article/abs/pii/S15587...

Dogs can be trained to find a bar magnet

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6301327/

We excluded visual cues and used control trials with food treats to test for the role of olfaction in finding the magnet. While 13 out of 16 dogs detected the magnet significantly above chance level (53–73% success rate), none of the dogs managed to do so in finding the food treat (23–40% success rate). In a replication of the experiment under strictly blinded conditions five out of six dogs detected the magnet above chance level (53–63% success rate). These experiments support the existence of a magnetic sense in domestic dogs. Whether the sense enables dogs to perceive MFs as weak as the Earth’s MF, if they use it for orientation, and by which mechanism the fields are perceived remain open questions.

So maybe there is some value in p-hacking, when taken with an appropriate grain of salt? The problem is science journalism and its readers often don't know how to do that.

> Maybe you should have started with that, rather than anecdotal evidence.

Oh dear. You mean I didn't approach this topic with the care it deserved?

> High school students...

Good for them! I only glanced at it, but it looks interesting.

> Dogs can be trained to find a bar magnet...

I read this. Right away, I can tell you the authors didn't take nearly enough care to eliminate the dogs' olfactory sense from the data, and the proof of that is that the dogs couldn't locate the jars containing food. Dogs should easily have been able perform that task, as anyone who operates a sniffer dog will confirm. The fact that these dogs couldn't do it means something is wrong, and I'd bet money that the problem was that the jars were handled in such a way that they all smelled of food.

To be fair, this would be quite hard to get right. Dogs have a sense of smell that can seem downright supernatural. When I was in high school, Denver PD had a bloodhound named Yogi who tracked down the body of a murdered child who had been transported ten miles by car. Yes, by car [1]. In training exercises, Yogi was able to track things that had been sunk thirty feet underwater at a local reservoir.

That craziness obviously presents an enormous challenge when designing a study on another hypothetical dog sense, and while this study went to some length to address it, something clearly slipped through the cracks such that the study's "food" arm (which was intended to serve as a control arm) was rendered useless. It also makes me strongly suspect that the magnets were also handled in such a way that there was some olfactory indication of which jars contained them. The paper doesn't tell us how the preparers handled the magnets and their containers, and there's no indication that they took measures to either prevent the transfer of any odor from the magnets to the jars, or somehow ensure that the odor was transferred equally to all jars.

My skepticism notwithstanding, I'm fascinated by the concept of magnetoreception in animals, especially birds, and I think it definitely deserves extensive study.

1 - Look up the Alie Berrelez murder case.

Police claimed that Yogi could smell whether a car carrying the victim had driven along the highway or down the exiat ramp, 4 days later. Supposedly the car exhaust blows your body cells out of the car and somehow into the ground but stays within a range of a few dozen feet. It doesn't pas the sniff test. Something else was going on, maybe a tip-off and the dog was cover for it.

https://unsolved.com/gallery/alie-berrelez/

> It doesn't pas the sniff test.

Was this pun intended? If so, well done!

I've heard some conspiracy theories in my time, but that's surely one of the lamest.

This was a search for a child who may still have been alive, and a suspect still at large. The cops were begging for tip-offs. Why in the fuck would they waste days or even hours with a fake search in order to "cover" for anything? Yogi worked out in the open, and he had an audience. Civilians were involved in the search, and in fact the body was actually found by a group of students who were assisting. People were able to watch the dog repeatedly lose the scent, backtrack, and pick it back up, working his way up into the canyon. That would be one hell of a dirty, dishonest performance by Yogi's handler, who by the way is still active in the K9 community.

Nobody knows exactly how Yogi did it, but given that dogs are to known smell at parts-per-trillion levels, and that there are many ways the killer's scent could be transferred to his own car tires, I don't think it requires an excess of credulity to take the police at their word.

That's an awful lot of unsubstantiated speculation. This has the vibe of a writer that has a foregone conclusion which they seek to reach.

Lots of pooping happens at night too, though...

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