Took our 9yo cat to the vet's last week, clean bill of health except for some bite marks at the base of the tail. Vet diagnosed this as fleas, tried to sell us Frontline. But, I'm 100% sure there are no fleas in the house, including the crawlspaces she likes to go into. Also no evidence of any fleas on the cat, and she's 100% indoors, with no other animals in the house. I'm wondering what else those bite marks could be, if not fleas? Notice she bites herself in that area occasionally, but didn't think it was enough to cause scabbing. Just don't want to go through a 3-month flea treatment for nothing.