I have a three year old rat terrier that about 4 months ago started chasing his tail.  He will be fine and then he just starts growling and barking and going in circles to attempt to bite his tail. I took him to the vet in February because he was scooting on the carpet and they had to express his anal gland.  The vet checked his prostate at that time and everything is healthy, EXCEPT for the tail chasing.  He normally does it several times a day.  I don't know if it is allergies but I think it is very coincidental that it started around the time I took him to the vet in Feb.

Has anyone else experienced similar issues with their rat terriers? 

Thanks,

Stubsmom

Oh yeah, Daphne chases her tail all the time.  As a matter of fact, she chased her tail so hard on Saturday night ( she didn't catch it, I might add) that she wore herself out and literally fell asleep out in the middle of the floor.  Sometime I will hear her growling in another room, and when I go check on her, she will be growling at her tail.  

I never assumed it was abnormal, though.  I figure as long as she is not gnawing her tail off then she must just be playing.  I find it pretty hilarious.