Rat seems clumsier, rubbing himself against things.

Question
QUESTION: Two days ago my usually affectionate and friendly rat (around 5 or 6 months old) bit me very badly, gashing my arm open. He had been acting nervously beforehand, but the attack itself was seemingly unprovoked - he ran up my arm as I was sitting in a chair and suddenly sunk his teeth into me, hissing. Since then he has not been aggressive when handled, and I was hoping it was a one off - but I've noticed some other changes in his behaviour that make me worry that there is something strange going on. He's always been fairly clumsy but he seems to be falling over while cleaning himself more, and missing more jumps than normal. As well as this he keeps rubbing his right side against things - my hand, the wall, a chair leg. I thought at first he was rubbing an itch as he has been a bit scabby as he turned out to be allergic to something in his old food mix - however on closer inspection it seems more like an involuntary thing, almost like he's losing balance. Could this be something neurological, and could that be related to why he bit me? I'm taking him to the vet as soon as I can get an appointment (hopefully tomorrow,) but I'd be interested to know if you have any opinions on what might be going on.

ANSWER:
Since I havent examined him of course, its hard to really be able to give a definite diagnosis.  I am going to be positive and say he may have vestibular disease caused by inner ear infection.  Inflammation in the inner ear from infection can cause pressure on the 8th cranial nerve in the brain. This is what controls equilibrium and may be responsible for his loss of balance. They also may develop a head tilt with this condition too. Antibiotics and steroids or even an NSAID (I prefer streoids actually) for inflammation and a bit of time for everything to take effect and they usually recover without incident. Sometimes if the rat develops a head tilt, this takes longer to recover from and if it was severe, they may not get rid of it totally but can live with it just fine.

However, the aggression has me stumped. Reacting the way he did is sheer aggression, but what was he reacting to?  Sometimes an intact buck gets super hormonal around this age, or a bit older, and they will mark things not only with urine, but by rubbing the side of their body against things. Sometimes they will brush up against their opponent  sideways, like they are marking the other rat or something. They also will do this against objects. Usually when they see another rat or even another animal they feel territorial around.  You said he seemed like he was losing balance when he did this, so I may just have a different image in my head.   Something scared him though, and to make him hiss and bite you is really really odd. I have only heard two other bucks hiss and they were raging mad at another rat. Stupid me broke up the fight and yes, I have nerve damage in two fingers that took the bites. live and learn, I guess.
Where did you get him from? If he came from a breeder, I would call the breeder and ask about his background. If he came from a pet store etc....there is no way to know his temperament and chances are he was inbred more times than Sara Palin says "MAVERICK."  

Does he have a cagemate?  I am going to assume that he doesnt since you didnt mention how he gets along with other rats etc..

Also the vet, is your vet an exotics vet or a vet that has a specialty with exotic companion animals?

Whatever is wrong may be black and white and a vet that is up to par with rats should be able to at least have an idea or two as to what is going on.  I am curious myself actually since this is only a virtual diagnosis and of course an educated guess because of the lack of being able to do a hands on exam.   Please keep me posted. How is he tonight?

---------- FOLLOW-UP ----------

QUESTION: It is very possible that his rubbing behaviour is what you have described - he only does it to certain things or in certain places, like the base of the floor lamp and the side of certain chairs, and he's always been something of a klutz anyway, so it wouldn't surprise me if he overbalanced occasionally while doing something like that. I certainly hope it is a territorial thing rather than any balance problem, as apart from ripping my arm open, he generally has a lovely nature (possibly the smartest of all the rats I've had - he worked out how to unzip my bag!) and I'd be sad for anything to happen to him.

My local vet is part of a group which has two exotic animal specialists in the area, so I should be able to book to see one of them.

He was a pet shop rat I'm afraid - although from a very good shop, so I might go and ask the owner if she knows his background - and he does live alone. He was the last of his litter when I got him - he was so sweet and friendly (not to mention tiny) I just couldn't help myself! I have tried introducing him to friends' rats to see how he would react to a cage mate - he's fine around other rats on neutral ground for short periods of time, but has shown himself to be rather dominant and short tempered on occasion and I'm loath to get another rat without knowing first whether he would tolerate them and then have to keep them, even take them out separately if they don't get one: considering that Kije is out of his cage and with me pretty much whenever I'm at home, it would impact badly on his quality of life. Since I am a student and funds are limited I also don't want to take on another rat if it would mean providing substandard care for both of them, rather than the best care for one. Still, I feel bad for him living without a rat buddy, I just wish I could take a rat on a trial basis!

Tonight he has been pretty normal, although earlier on he had what my flatmate termed a "hectic moment" on the table - darting from side to side and chattering violently - even though there wasn't any stimulus apparent to us (of course, I don't have his sense of smell or hearing.) This is part of what makes me worry there could be an underlying problem, although I also wonder now whether he could be highly hormonal at the moment - he has been scent-marking more recently. If it is hormonal, is this change permanent, or will he chill with time, and would neutering him help?

Answer

The fact he doesnt like other rats....he may be having issues with aggression.  I would neuter him. Do you have a good exotic vet? If not I can find one for you and give you some names of vets in your neck of the woods.  I do think neutering will help. The fact he acts uber aggressive now at his age just doesnt seem like he will outgrow it. I dont want you to become scared of him. If he picks up that you fear him that could throw him off even more.  I dont think he is ill, however, but the vet will check it all out for you just to be sure.