My dog snoop has been doing this the last week on and off and loads this morning.
As anyone else had this happen to with their dogs before and any ideas on what it means?

Every time I stroke his head he chatters his teeth really odd ?
The only other thing I notice is that the hair from his tail is raised up half way up his back in a square shape. 

The hair raising makes me think its his 'spine' coming up (sorry dont know the correct term) which only usually happens when irritated or upset but if he's chattering as well it sound slike excitement?
Has he just been playing with his toys and getting really excited before this happens or do you have a bitch which he has just had a sniff  of her bits before he starts chattering?
Only saying because My bitch Stafford will chatter when she becomes ball obsessed and has had a good game of fetch and my boy stafford will chatter when he's smelt Mitzys bits lol

Only time Ive encountered it so hope it helps?

Hackles rise when the dog is aroused by something, but the teeth-chattering is often sex-related. Is there a bitch in season nearby?

Another thought - how old is he?

My boy snoop chatters his teeth when my girls are in season, it gets that bad he bites his tongue and makes it bleed.
There could be a in season girl close by that he can smell.

> but the teeth-chattering is often sex-related. Is there a bitch in season nearby?
>

Thats what my Sparky does!! LOL, whenever there is a bitch around either just come off or in or even just a lady friend he fancies, his jaw chatters.. people think he is cold, but its a different chatter, its like his lips arent attached to his face lol!!

In the absence of an in-season (or possibly just about to come in) bitch in the house or vicinity, it may be a pain response. 

My older girl was recovering after an op recently and after the initial pain relief wore off she did this now and again for the next 48 hours when her twice daily meds were wearing off too.....

Usually teeth chattering is associated with an aroused response

> Usually teeth chattering is associated with an aroused response

Buster used to do this quite a bit when he was younger, mostly when he saw my sister (he LOVES my sister), occasionally he'll still do it when my dad or sister visit, he gets so excited he quivers and his chops chatter a bit (along with major butt & tail wagging).

In-season humans might also be met with a similar response. Just one that hasn't been mentioned.

>In-season humans might also be met with a similar response.

One of my dogs always lets me know when female guests have 'a visitor'.

I would of also thought of pain somewhere i.e. back or neck.

How come my boy Turbo gets the chatters when he sniff Mitzy if its sex related?
She is spade so has no pheromones as such, he does get his nose right in her bits tho lol!!

Definitely a 'kinky' thing with my boy.  Looks like something out of the film Alien is going to pop out of his head sometimes the way the muscles react after he's got a sniff of something 'nice'!
My girl has been spayed too Rach, but there is still scent in the urine too.

I posted recently about my spayed Samoyed girl who does this a lot - my Cavalier is in season at the mo and Megan can't take her nose away from Gypsy's lady parts... When she has stopped sniffing her she chatters her teeth just like male dogs sometimes do when they have been sniffing something particularly interesting. So in my dogs' case it is definitely a sexual thing (confused girlies)

Ahh thanks guys, so Turbo is just liking what he's smelling lol what a compliment for Mitzy as he only chatters when he sniffs her lady bits so she must be extra special lol

My girl will chatter if she scoots when her glands need emptying after she has licked it up.....or when smelling my other girls bits.

> In the absence of an in-season (or possibly just about to come in) bitch in the house or vicinity, it may be a pain response.

This is what the vet's thought when our pup was in hospital, chattering or grinding teeth

Diane 

Thanks peeps for all your replies-

After all your suggestions think it might be him being in discomfort with his back & neck injury.
Can't think him getting aroused anymore as had his bits off at 7 years and he's 9 now!

I thought it might be all the medication he is on and was acting like he needed a fix lol

Most probably with Snoop he was rather upset this morning- I came down to a house filled with gas fumes! Starsky had turned on the knob on the cooker and nearly gassed them all !! Snoop was in the lounge but the other 2 were in the kitchen luckily had a window open for the cats!! 

my 3 month old puppy chatters her teeth when she see's me eating or holding food... surely thats not sex related??

My older pup does it if I hold a treat but make her wait for it. I just put it down to excitement.