Although, the subject is about dogs, this is question is about mammals who mark in general.
So dogs are said to mark so as to leave a calling card identifying themselves.
So are there unique compounds in their pee identifying individual dogs like fingerprints ? (I am assuming these compounds are identified using Gas Chromatography / Mass spectroscopy at the ppm/ppb level )?
And if they have these unique compounds, which organ in a dog (or any mammal) for that matter controls them ?
WAG (if this is not allowed in GQ let me know):
Urine is a waste product as is affected by what the organism consumes. I would be willing to bet, in your lifetime, you have noticed that your pee can change in character from one pee to the next. If you want to test this go pee, then eat some asparagus and pee again and see if you notice a difference (that one always kinda amazes me…not sure if this works on everyone but it is common).
I do not think there is enough there to identify an individual though beyond gender. Perhaps if a given animal in an area has a consistent diet (as many house pets would) their pee may be distinct to them. What goes in is largely the same so then what goes out is too. Perhaps that would be enough to identify an individual.
Out in the wild with less consistent diets…not so sure.
There can be a hormonal component too (which is sometimes how they know a female is in heat) but again…not sure if it tells them more than there is a female around ready to breed rather than Susan is good to go but still waiting on Karen and Julie.
Maybe. The canine sense of smell is pretty remarkably acute. It seems likely they can identify self from other. So it also seems likely that they are able to distinguish individuals, but whether they can go the next step to accurately identify individuals by linking the two mentally is a tougher ask. Whether they can zero in on any specific known individual dog (“Oh that is Rex’s pee, I first smelled him last week at the dog park”) doesn’t seem to be definitively established.
A friend of ours says when her dogs are sniffing things on their walks “they’re checking their pee-mail.”
To the extent that dogs can identify individuals, I would expect it to be based not on unique compounds, but on the ratio of different compounds in the urine. That ratio may be somewhat stable over time and allow individuals to be identified.
This is my thought too. It was always my understanding (and if this is a misconception please correct me) that for a dog, smell is the primary sense and the one that the whole mind is built around, the same way our primary sense is vision.
Anecdote::
When I interact with dog(s) then return home, our dogs sniff my pants, obviously aware I’ve been around dog(s).
However, when the dog I interacted with is my daughter’s dog, who they know and have spent time with, they sniff my pants and go absolutely bonkers.
If you observe dogs closely their behaviour is different in these contexts:
Sniffing a marking post in a familiar, often-visited place vs a new place never visited before
Sniffing a dog they have met before vs a dog that is new to them
In both of the latter cases, I have observed what appears to be more careful and considered study of the thing they’re sniffing, which I would argue implies they can differentiate between the scent of known and unknown dogs, and probably discern between known dogs
There are humans who can identify other specific humans by scent. If we can do it, of course dogs can, too.
Absolutely correct. We can’t ask the dogs to get the answer because they are know liars but observation shows this behavior consistently.
Dogs can certainly identify you by scent.
But that does not answer if they can identify your pee as yours.
Maybe they recognize certain characteristics – sex, spayed/neutered or not, size, breed, diet. If they recognize a strange new combo, it might be a new dog. Or the next door dog might have just started a new diet and smells a bit funny, like seeing someone you know in a new hat.
This map that tracks the movements of six wolf packs in a park* shows how well they can distinguish between the members of their own pack and other packs. They may see or hear each other at times but I think there’s no question that scent is the primary way they maintain these borders.
It still doesn’t tell us if they can tell one member or their own pack from another purely on the scent of their urine. It seems possible that whatever allows dogs to distinguish us by scent otherwise could be present in our urine even if it only is there in just trace amounts.
*Map linked to from this thread: ? Awesome Maps
When our guys pee on something vertical we call it, “leaving a message on the bulletin board.”
P-Mail is what we call it. Same idea though.
Hard to say, but both dogs and cats seem to identify their kind and humans by smell as much as anything. Cats also sniff the rear ends of other cats, I am not sure what smell they are trying to identify, but given that they have much more sensitive noses than humans, it is possible that they can identify others by smell. Of course, it is not easy to get definitive proof.
Dogs’ sense of smell so dwarfs ours that even imagining it is difficult. “They possess up to 300 million olofactory receptors in their noses, compared to about six million in us. And the part of a dog’s brain that is devoted to analyzing smells is about 40 times greater than ours.” (quote from a veterinary site)
Dogs can smell dead bodies under running water. They can smell cocaine when masked with other scents so strong even humans can smell them easily. They can smell if someone is about to have an epileptic seizure. They can smell that an earthquake is imminent. Their whole world is odors talking to them all the time in a language we have no way of understanding.
You bet they can smell different dogs. They can smell invisible paw prints from days before and recognize dogs, why not urine?
If a dog is marking a spot, they’re also marking the ground with the scent of their paws. So any dog known by scent can be identified by their ground trail and then associated with the smell of their pee.
I’ve heard that dogs infer the size of other dogs by how far up the marking spot the scent of their urine goes. (Feel free to debunk.) I’ve seen a couple of dogs convolute themselves to get their pee as far up the marking spot as they can.
Some animals also have glands that mix a more personal scent into their urine. The scent from those glands are often produced by bacteria in the gland. Individuals that spend more time together tend to have similar bacterial mixes, so that the scent of the urine not only identifies individuals, but who those individuals are related to by pack and level of intimacy.
We know dogs have super snoots that have amazing sniffing capability.
The question is can they discern Rex’s pee from Mollie’s pee from Fido’s pee over the course of a month. No doubt they can tell there are three dogs but do they know which is which?
Now imagine them in a dog park where dozens of dogs have peed. Is your dog able to know all who have been there by smell?
That’s what I took the OP to mean: do dogs maintain a database of scents that can link a smell back to a particular dog.
Remember the game show, Concentration ?
I think it’s a great question.
I reached out (as I’m wont to do) to my yellow lab for a consult but all he did was lick me (and, by “me,” I only mean the guy sharing the couch with him at the moment. He regards me as a total stranger with kitchen access and a car).