Kitten biting when pet

Our kitten is around 5 months old. When we pet him anywhere below the shoulders, he immediately starts rapidly biting whatever is in front of him. He doesn't get aggressive or show any signs of pain, it seems to just be an automatic response. It also seems to get more rapid and intense the closer we get to the base of his tail. He doesn't turn to bite the person doing it, and even purrs while this is going on and seems to be enjoying the petting. He's been exhibiting this behavior since we got him a few months ago, when he was around 2 months old. He was neutered about a month ago, but the behavior is the same post- and pre- neutering.

When I search for kitten biting when pet, the response that turns up is stuff about over-stimulation, but the descriptions I read about it don't seem to fit with his behavior. Can anyone shed some light on what might be causing this? Is this anything we should be worried about?

Thanks.

Does he bite really hard? If he 'bites' softly, it is more a sign of affection.

But I think you mean he is biting hard.

Possibly, this kitten is not well socialized. Young kittens learn from their mother and also from their owners what kind of behavior is acceptable or not.

However, I think this more has to do with limits.

Like humans, cats also have limits. We would not like it either if people touches us constantly.
Does he gives any warnings before he bites? Most cats first give warnings through body language.
Some cats run away when they have had enough. For others, first the ears go back, then starts to wag the tail and if you do not stop, the cat will bite or scratch. For cats, this is rational: after all, he has already given some warnings and you still kept petting him.
Some cats do not give a warning. This may be caused by owners (in the past) who systematically ignored the body language of the cat. Then, a cat decided to get right to the point

Suddenly scratching or biting when a cat is petted, is officially called pet aggression. (Excuse me if this is not the right term in English, my native language isn't English).
The best way to prevent this behavior is to read the body language of the cat. Has he seen enough, leave him alone and respect his boundaries. Never respond with a tap or any other form of physical 'punishment', because then you provoke this behavior.

Hm, it's not quite the same but my cat does something similar.  It is only when I clean her butt, never when I'm petting her normally.  Sometimes she doesn't clean her butt well after a poop and I have to help her a little.  It is probably uncomfortable.  Anyways, she will start rapidly licking herself and even biting (biting in the way that cats sometimes do when bathing themselves.) It kind of seems like when a human wants to bite down on something hard or squeeze someone's hand when they are in pain.  This is all just my conjecture, however. 

Anyways, if I were you I would avoid petting kitty below the shoulders too much until he gets more used to it.  Maybe introduce petting gradually.

It may be that your cat has very sensitive skin and is easily over stimulated with petting, esp lower on his back, however it might be worth checking with your vet to make sure he doesn't have anything which is causing him pain as it isn't always obvious and could give rise to the same type of behaviour.   If you don't know what his life was like before you adopted him be aware he might have had some experience that left him feeling anxious or with painful memories when touched at the base of his spine, but it is a commonly sensitive spot that some cats do not tolerate being touched.

As long as he does not have any health issues, you can try approaching him slowly from the side and limiting strokes and petting to his head and upper body areas for now and gradually see if he gets used to you - if you approach face on some cats find this threatening and it can also add to the type of response you get to petting.    Keep petting to short periods of time and gradually increase so you can learn how long is too long for him.   You can also test and see if you can desensitise him to being touched lower on his back by using toys ton touch him during play, like feather wands or larger kicker toys and touch gently but firmly.  That way it will hopefully be the toy that takes the 'hit'.   

If you haven't read them already there are a couple of interesting articles on TCS around this type of thing:

http://www.thecatsite.com/a/cat-aggression-toward-people

http://www.thecatsite.com/a/re-directed-aggression-in-cats

http://www.thecatsite.com/a/when-physical-problems-turn-into-behavior-problems

Good luck, your little guy is still young and his behaviour will no doubt change as he matures and his high octane kitten energy fades a little.  This too will make a difference to how much petting and cuddling you will get away with.

Thank you for the replies. As I mentioned in the original post, he's showing no aggression at all towards people. He just rapidly bites/nips whatever is in front of him (usually a blanket, the couch, the floor)  once you start petting below the shoulders. He also doesn't seem to be in any pain, as he is purring, doesn't get up and leave, and doesn't turn around to bite whoever is petting him. He exhibits the exact same behavior as when we're petting him on the head, just with the addition of the rapid biting. It's actually like an on/off switch - it stars and stops instantly as you move from the head to the back then back to the head, but no other changes occur.

There were some mentions of the previous owner, but the previous owner mostly ignored him from what I understand, and he was living in the house alone with two small dogs for a long period of time. The whole reason we took him in is because our neighbor had rescued him, but they didn't actually want a cat. They were moving back into their house, and were about to take him to the pound, so we decided to take him instead. So his interaction with humans and any conditioning he would have gotten from it would have been very minimal.

It almost seems like his behavior could be due to skin (allergy) or nerve irritation. Almost like he is itchy or has the tingly feeling like when your feet fall asleep...that would explain why he purrs when you are scratching/petting him...it feels good or gives him some relief.

My oldest has something similar...only he has "licky spots" where he'll start licking the air when you get to certain places on his back. I'm certain it is due to allergy and/or nerve issues.

This might seem strange but cats don't only purr when happy and comfortable, they can purr when in pain.  It might make sense that he is over sensitive or has skin irritation and worth checking out.

No idea whether it can happen but I also wonder if most socialisation has been with dogs whether he might have learned some behaviours from the dogs that were his companions, esp if he didn't get a lot of attention from the person he lived with?

I apologise for not noticing your cat is biting objects rather than people.  Don't read too much in to the word aggression in the article titles, it is often the easiest way to explain a biting or scratching behaviour (toward a person or in response to contact with people) rather than a specific and intentional act of aggression.  There may be some piece of information in the articles which could trigger an idea for you about why your cat is doing this.  

Thank you for taking this cat in and caring for him as he learns to socialize with people.  He is very lucky in deed to have met you.  

Not sure how relevant this is but when I was young we had a cat that would lick really fast, anything which was in front of him. The closer you scratched to the base of his tail the faster he would lick, it was almost like when you scratch a dog and their back leg starts to go like they want to scratch. He was perfectly healthy in every way, it was just his funny little quirk. He lived until he was 20.

Thanks for the replies again. What CatPack and KittyWhiskers are describing about their cats seems the most similar, just with rapid biting instead of licking. It's a relief to hear it didn't seem to be a problem with your cats. Hopefully it turns into licking as he gets older, but we can certainly live with it if it doesn't. So long as he's healthy.

Blighty Likes To Be scratched just above his tail.