>but do other animals exhibit the same effect? I have an arthritic cat whose hind leg occasionally pops as loud as my knuckles. I don't know if it's the same p

>but do other animals exhibit the same effect? I have an arthritic cat whose hind leg occasionally pops as loud as my knuckles. I don't know if it's the same phenomenon, but it sure sounds similar. No, you can't probe her. :)