Quiet and a Calm dog suddenly aggressive with food.?

Nothing wrong with him other than you giving him a treat then stealing it from him

You should endevour learn a little about the nature of dogs then in that case. Take the dog for a vetcheck. its health may be deteriorating at that great age.

Geez,

IMO both Jojo and V are right. Jojo was right in that you approached the dog incorrectly -

BUT (IMO) you should never have had to TAKE the treat back - that was STUPID. You ought to have cut it or broken it, BEFORE YOU GAVE IT TO THE DOG. If that was not possible - until you saw a too large piece likely to go down WHOLE, then in the last 11 YEARS living with you.......the dog OUGHT to have LEARNED the COMMAND to "DROP IT", or you ought to have been able to "TRADE" - for a piece of some other nice treat.

The odd reaction you got is (most) likely due to approaching the dog from behind, rather from the side or front. But as as also been strongly suggested, it also means it is time to see the vet for some examinations especially regarding teeth & eyes, ears, and perhaps joints anything that may cause pain or not be working well and "alter" the dog's perception.

Regardless, with the extreme reaction, I would NOT EVER give this "treat" again.

YOU Shouldn`t have "snatched" at the treat while he was still eating it.

That`s enough to set most dogs off on the defensive.

Old dogs can get very grumpy at times and forget their manners, and also you should have not have touched his back as he would have seen that as a threat from something he could not see and would obviously growl.

You "should" have approached from the side so the dog could see you and then spoken to him or called him to you. He may have then dropped the treat of his own accord.

Everything you did was viewed as a big threat, so of course he acted accordingly.

Yes, of course you should be able to remove food from your dog without any issues, but only if you go about it in a firm and confident way and not in the way you went about it all.

Sometimes we can forget our dogs are animals, and we forget to see things in the way they see them, and we make silly mistakes on our approaches to them sometimes, which confuses them, and their primitive instincts come into play automatically.

Be more careful in future eh? Jmo.

Don't give him this treat again. By now he should have learnt to 'drop'/'leave' on command but many dogs will resource guard so you'll have to keep one step ahead so he doesn't get anything that might cause him harm, and once he has a treat or his normal food, leave him alone.

Now might be a good time to get him in for a health check - including a dental because it could simply be that his teeth/gums hurt meaning he knew he couldn't eat the treat easily, so he walked away with it, to eat it at his own pace.

I hope by punishing him, your didn't hit him!! This would only make a bad situation worse.

Don't give him those treats, anymore. If there may be any health issues, take him to the vet.