11 yr old jack

Question
we have had our 11 year old JR since he was 8 weeks old and he has always
been a great dog - a very typical JR, but has fit in well with our fmily - always
tolerant and patient with the kids and our other dog until about 6 months
ago.  Now he is very cranky, disobedient and has been snipping at all of
without any obvious triggers.  We are concerned about this aggression - we
had a previous JR a long time ago that we had to give up that even the JR
rescue wouldn't take because of her aggression issues, but this is new for this
dog.  Do JRs tend to get cranky in their old age or should we be concerned
about a health issue that isn't showing itself to us that could be causing it?  
We don't want to have to find a new home for im, but we can't tolerate him
biting us either.  Any ideas?

Answer
Hi Gayle,
If this is a sudden change I would definitely take him to the vet for a good check up. If he is in pain he has no other way to tell you other than being grouchy and snappy. 11 years is 84 in human years, he could definitely be experiencing some physical discomfort and problem. It could be ANY number of things from a toothache to something more severe. Dementia is another possibility for a dog in this age and he may not even know he's doing it. Definately take him in to be seen. Good luck with everything.