Anybody who walks a dog knows that dogs are normally selective about choosing a spot to defecate. They sniff around for a long time, while I just want to be on my way.

I understand about marking territory with urine. Is it the same with feces?

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    $\begingroup$ As a dog owner, I personally don't find dogs so complicated to please for pooping spot. They sure investigate the ground for good peeing spots though. $\endgroup$
    – Remi.b
    Dec 4, 2017 at 16:00
  • $\begingroup$ Well then your experience is very different from mine, which was the reason for the question. $\endgroup$
    – Karl Kjer
    Dec 4, 2017 at 16:05
  • $\begingroup$ By your own admission the OP is primarily opinion based, thus, I VTC. $\endgroup$
    – user22020
    Dec 4, 2017 at 19:54
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    $\begingroup$ @Charles and Remi.b, while dogs do certainly have different personalities, being picky about the spot where to defecate (not only to urinate) and spinning around before doing so are very common behaviours (not the exception), and well documented. $\endgroup$
    – user24284
    Dec 5, 2017 at 2:37
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    $\begingroup$ @GerardoFurtado IMO, the OP comes off as opinionated and subjective. I'm not debating that dogs do or don't perform these behaviors, but instead, I have an issue with the manner in which the OP contextualized and supported their claims & question. $\endgroup$
    – user22020
    Dec 5, 2017 at 2:49

1 Answer 1


Marking territory with faeces

Despite urine being the most common way for dogs to mark territory, they also can use faeces to do so. Not only the faeces have a unique scent for the dogs, but, most importantly, it contains secretions from the anal glands, which are very important in dog communication. In fact, when you see two dogs sniffing each other "behinds", they are smelling the other dog's anal glands secretion.

So, being selective about the place to defecate is indeed an expected behaviour in dogs.

Magnetic sensitivity in dogs

However, if you are specifically talking about the dog spinning around after it — more or less — decided where to defecate (which makes the dog seem like it had not yet decided if it is going to defecate or not) one factor that plays an important role is that dogs like to eliminate with their bodies aligned to the North-South axis.

According to Hart et al. (2013):

Dogs preferred to excrete (sic) with the body being aligned along the North–South axis under calm Earth's Magnetic Field (MF) conditions. This directional behavior was abolished under unstable MF. The best predictor of the behavioral switch was the rate of change in declination, i.e., polar orientation of the MF.

So, the dog has to spin some times until it finds the desirable orientation, which explains the behaviour.

It's worth mentioning that the interesting aspect of this research is not the fact that it explains why dogs spin around before eliminating, but the fact that it shows that dogs have magnetoreception!

Still according to Hart et al. (2013):

It is for the first time that (a) magnetic sensitivity was proved in dogs, (b) a measurable, predictable behavioral reaction upon natural MF fluctuations could be unambiguously proven in a mammal, and (c) high sensitivity to small changes in polarity, rather than in intensity, of MF was identified as biologically meaningful.

Source: Hart, V., Nováková, P., Malkemper, E., Begall, S., Hanzal, V., Ježek, M., Kušta, T., Němcová, V., Adámková, J., Benediktová, K., Červený, J. and Burda, H. (2013). Dogs are sensitive to small variations of the Earth’s magnetic field. Frontiers in Zoology, 10(1), p.80.

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    $\begingroup$ And what would be the reason to defecate aligned to the N-S axis? $\endgroup$
    – have fun
    Dec 5, 2017 at 7:20
  • $\begingroup$ Well, that's a very interesting question, which will need a lot of research to be answered. Since this paper is quite new, I doubt any other team have already studied the reason of that alignment. $\endgroup$
    – user24284
    Dec 5, 2017 at 7:24
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    $\begingroup$ My dog is defective. Given a choice, he poops facing east, which is almost all the time. My girls are smarter. They don't obey any inner magnetic nonsense. They just find a spot that feels right to them and do their business, And I pick it up, which makes me a desecrater in their sight. Foolish human. $\endgroup$ Dec 6, 2017 at 3:01

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