Overweight cats chew the air, or anything in reach, when you scratch the top of their tail.

Heavy cats will sometimes chew the air or anything they can reach when they can’t get to it themselves. Heavy cats can’t bend around far enough to really sink their teeth into the itchiness of their own rump – so the ‘tail-scritch-air-biting-thing’ appears to be a reflex, a ‘release’ of pent-up chewing that they’d RATHER be doing to their own tailhead (top-base-of-tail) but simply, mechanically can’t.

It can be a BIG liability if someone is petting the head-end of the cat while someone else scritches the tailhead.

Further, some people worry that the cat is in PAIN  –  clients mention “We thought she had arthritis and it was tender” as the reason she bites when touched there.

The cat’s not angry, or in pain when it does this. It’s supposedly part-pleasure, part frustration.

Is there some kind of treatment?

Well, kind of. Weight loss can help a cat “get around to its own butt” and that’s nice. But weight loss in cats MUST BE SLOW because their liver can be ruined (fatty infiltration) with rapid weight loss. So you kind of get stuck limiting AMOUNTS of food but never really letting the cat “not eat”. I don’t even recommend changing foods in case the cat ‘goes off feed’ and contracts “hepatic lipidosis”.

Usually cutting back a tablespoon or two a day will exert some slow weight loss.

If the cat is pruritic, (itchy) then correcting the causes and condition of “itchiness” will reduce the impact of the rump-scratch. I sometimes like cortisones for this, but since those may trigger diabetes in a vast minority of cats, it should be weighed against the risks.