[chris (OP)]

Recently on the Naked Scientists we discussed why cats play with the animals they catch before they eat - or abandon - them. The answer was intriguing: https://www.thenakedscientists.com/articles/questions/why-do-cats-play-their-food

However, this stimulated another discussion more recently: "Why do dogs chase their tails?"

Anyone know?

[RD]

..."Why do dogs chase their tails?"... 

Stereotypy seems to be the most probable reason ... https://en.wikipedia.org/wiki/Stereotypy_(non-human)

But some apparently don't realize their tail is part of them and will bite it as if it was another creature, so like somatoparaphrenia.

[alancalverd]

Initially, I suspect curiosity - "what's that thing in my peripheral vision?" or possibly irritation - needing to bite an itch. I think dogs grow out of the habit when they realise that the tail is under control (puppies spend a lot of time calibrating their bite and learning to scratch accurately, possibly the tail is the last bit to get fully controlled) and can be better reached by lying down.

Utterly fascinating species altogether, with the intellect of a 3-year-old human and the strength of an adult. And the only other species with which we actually collaborate.   

[chris (OP)]

Dogs set great store by the tail - it's the canine equivalent of facial expression. I'd therefore be quite surprised if they randomly thought it wasn't part of them; I'm also a bit (bite) sceptical that it's used as a bit calibration device - why not use a paw, or their flank in that case?

I think they realise it's part of them, and I think they regard it as a game, or possibly a form of dog yoga?!

[alancalverd]

Apologies for ambiguity. Puppies calibrate their bite by chewing and playfighting, which suggests that just as humans aren't born with the ability to walk, play the piano or throw darts accurately, quite a few motor functions have to be learned or at least polished in some mammals, hence puppy chewing etc and my suggestion is that as the social function of the dog's tail has to be learned, some of its early movements may be a bit random.

Sort of related: dogs and cats have long, heavy tails compared with their herbivorous prey. I've often wondered if this actually helps them run fast? Imagine if you had a second minibrain at the lumbar/cocxxyx junction (as some dinosaurs certainly had). At full gallop, you just need to control your front legs consciously: the minibrain senses the angle between the tail and the lumbar spine, and uses this to drive the rear legs in the appropriate phase - steer at the front, automatic power (or pursuit afterburner) from the rear. Works for cars, and dogs certainly like to be scratched just about where the control system should be, suggesting lots of nerve sensors at the base of the spine! 

[evan_au]

Maybe when they are puppies, any real prey would escape.

So maybe when they practise pursuit, flexibility and strength exercises, they chase something that never gets too far away - their own tail?

But I'm sure that if there was a litter of puppies, they would spend more time chasing each other. We just have the habit of separating the litter off to different human homes, so there is nothing else to play with (without getting into trouble for chewing shoes, etc).

[Colin2B]

Sort of related: dogs and cats have long, heavy tails compared with their herbivorous prey. I've often wondered if this actually helps them run fast?

When I was at school our family went camping on a site where the owner would drive around in an old jeep and his dog would chase the jeep. Nothing odd about that except the dog only had 3 legs and its tail would go round like a propeller. It convinced me that dogs use their tails to balance.
I’ve seen a fox walking along the top of our fence - 12mm wide - and I’m sure that it must use its tail to balance.
Some while ago I saw an article about a 3 legged dog that had a problem with its tail and had difficulty running.
Also found this article https://www.nationalgeographic.com/animals/2018/10/amputee-three-legs-animals-news/

Balance must be important when running fast. Just thinking of cheetah with strong tail. Certainly would help when changing direction.

[bennieAligh]

Can dogs get stud tail? I know Tom cats can get it but its usually really greasy and obvious at the base of the tail.


Im not sure what it is but imagine it might be some kind of patterned hair loss, a lot of dogs lose hair on their tails, Ive never asked why :p