I've had my cat for just over ten years now, and I got him when he was still a small kitten. He has never been a mean cat. He doesn't like to be picked up and held but even then he won't bite, he will just flail around like crazy until you put him down. He's always been like that with being held. He does like to lay on laps though, and sleeps on my chest any time I'm laying on the couch watching TV.
A few years back, when I was still living with my mom, he would bite her in the feet all the time. To me it always seemed like he was playing but my mom did not find it amusing. He never seemed vicious about it though, and if she yelled at him he'd quit and run off - then come back purring and wanting pets.
When I moved a few years ago I brought the cat with me and he's never bitten me...until recently. Sometimes it seems very obvious he's trying to play. He'll get in the pounce position and start wiggling his butt, and then pounce. More often though he does not seem to be playing. One night he was sleeping on the back of the couch and woke up suddenly, and was staring at me very oddly. I mean I know cats don't really have different facial expressions for the most part, but he really had an odd look on his face. Then he jumped in my lap and just clamped on to my arm. I literally had to fling my arm to get him off.
He's walked by and bitten me in the foot or ankle, and twice now he's jumped on my bed while I'm falling asleep and bitten me in the head.
This has been going on for a couple months, but he's been doing it more frequently lately.
I don't want to sound like he's an attack cat all the time, he's not. He's still his typical self most of the time, but he's biting a lot more. And being bitten in the top of the head hurts!
When he does it I yell at him, shove him off the bed, whatever. Then I ignore all his attempts at getting pets for awhile.
Nothing has changed in his environment since we moved on 11/1/10, and this didn't really start happening until a few months ago. The cat gets plenty of attention. I'm home at night and my SO is home mornings and some afternoons. Also, he only bites me, not my SO.
Is he just playing? It just doesn't seem playful to me, it seems mean. I keep wondering if I'm doing something to cause it or provoke him, but if I am I don't know what it is. My SO thought I was exaggerating until he saw our cat attack my foot one night. He agreed it didn't seem like a playful attack.
Edited to add: I mentioned the flailing around when he's picked up thing - I don't pick him up unless I have to. It's kind of funny, but it really pisses him off so I wouldn't do it just because. Sometimes I have no choice though - he has escaped from our third floor apartment twice and I had to carry him back up all four flights of stairs. That was an adventure.
Does she have stomach issues or tremors? Since treating my cat for pancreatitis she has become much more mellow. Oh, and she also has tremors,twitching and when going through that will give me the hateful stares.
It may be thyroid related (at least it would be a likely guess in dogs where thyroid issues are relatively common, cats it's much less common but behavior & thyroid are very interconnected & the screen is relatively economic) so I'd start with a thorough bloodscreen.
Dr Jean Dodds is the world leader in thyroid investigation.
(she is trained as a vet & immunologist - truly amazing researcher & person!)
Pet Talk Radio has a number of interviews with Dr Dodds - listen to the thyroid 1 before your vet appointment
You need to be very careful. Every cat bite is serious. Feline pasteurella virus is some bad crap and you could easily get it. When my kids were little the dr always said to never ever let one cat bite go by, always bring them in.