Rat-aggressive Rat

Question
QUESTION: I have a male dumbo that is very aggressive towards other rats. I've tried introducing him to my hairless on neutral territory but he bit him several times in a few seconds. The hairless was about 2 1/2 months old at the time (he recently past away from a respiratory infection). I had the dumbo neutered, hoping it would get rid of some if not all of the aggression. I bought a young male rat from the pet store, I'm estimating that he was about 6 weeks old. They've had their cages close, to get used to each others smells and one meeting on my lap in a neutral room. My dumbo bit him so I waited a couple days. Today, I tried again (worst decision of my life). My dumbo got ahold of the little one around his neck and he bled to death before we could get to the vet. Is there explanation you could give me for why he's so rat-aggressive?

ANSWER: Hi Katie

I am so sorry for what occured.  As I was reading this I was actually saying out loud when I read you bought a baby rat around 6 weeks old to introduce to the dumbo......I was saying....."oh no...no no...not a baby rat..."  and thats when I got to the part where the dumbo killed him.

I was going to warn you against letting them together. Its not a good idea to let any male rat around a baby rat, aggressive or not.

However, I think you need to resign yourself to the fact that this dumbo, intact or not, is aggressive toward other rats and he needs to be alone. Its ok that he is alone. He obviously wants no part of other rats and thats ok.  Why?  Why is he like that?  Many reasons.  Inbreeding is the main reason, and if he comes from a line of aggressive rats, there ya go. Is he a pet store rat?
The thing is....does he bite YOU? There is a difference when your talking about aggressive rats.  If he cant get along with other rats PLUS he is a biter to humans, your dealing with some mental issues, but if he is just simply aggressive toward other rats, it can be hormones and inbreeding together.   When was he neutered?  How old is he now?

I have had many aggressive rats, from my wild girl, Holly, who, although she bit me to pieces I was able to train her and she was the sweetest little wild rat ever, but..yeah, always a BUT.....she hated domestic rats and they hated her. She would hiss, spit, hop sideways, spray urine at them (I had never seen this before with rats until Holly)  wild rats and domestic rats dont mix well at all which is why she hated the other rats so much.  I also had lab rats too that were mean toward humans but there was one big 3 pounder that charged at the other three lab rats and attacked them and me too. His problem was stress from being a test rat, no doubt.  I can go on.....

I do want to ask though, if your trying to put the dumbo with other males because you think he would be unhappy alone for the rest of his life?  If thats your worry, dont worry...there truly are some rats that honestly want to be alone and he is one that is proving to you that he wants to be the solo rat and I think after what just happened, I would just retire the idea of getting him a friend.  

Again though, I ask how long ago he was neutered...sometimes it takes some time for the hormones to drop and even out etc....



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

QUESTION: Through my research about rats I've gotten several different views on adult males and babies so that's why I was taking it slow, but apparently not slow enough. Several sites said that you should introduce the young one early so that the adult don't see them as a threat. But  I've also read that some rats just like to be by themselves so from now on he's going to stay by himself. He doesn't bite me or any other people just other rats. He was neutered a couple weeks ago but I guess for him that's not long enough for the hormones to balance out. I'm not sure of his exact age because I did get him from a pet store, all I know is that he's a young adult. His aggression towards other rats and unknown pedigree are two of the reasons I had him neutered. I love having a pet rat which is the second reason I bought other rats (the first being a cage companion) but from now on any new rats will be separate from the dumbo.

Is there any advice you could give me if I decide to get a pair of young rats from the pet store? (The reason I even getting rats from a pet store vs a breeder is due to the fact that there are no breeders located close to my town)

Answer
With a neuter, its 3 weeks to prevent pregnancy (really it is just about 8 days and sperm is dead but just to be safe we suggest a full 3 weeks before putting males with Does) but...and here is the "but" it may take longer for hormones to drop.   This could be why he was still aggressive with the pup. The websites that said adult males could be put with young pups is dangerously incorrect, as you have found. One reason we suggest to people that have the father of new babies to be removed at once is not only to protect her from pregnancy since Does can get pregnant right after giving birth, but to prevent the male from killing the new rats and yes, even at 6 weeks they kill them. Not every male will do this, but its not unheard of.  An adult male could be introduced to a younger rat who is more around 4 months of age, but its still not always an easy       transition. It depends so much on the temperament of the existing buck. I have had some super laid back rats that are willing to be friends with any thing that moves. Right now I have two solo bucks, ages 2 and 3.5 years of age. They lived with their own cagemates/brothers but both of them lost their cagemates a few weeks apart.  Bo, the older buck, is set in his ways and he was even a grouch to his brother, Templeton. Once Templeton passed away, I worried a bit about Bo and if he would adjust after being with Templeton for 3.5 years.  He seemed and still seems just fine and it has been over 6 weeks.  Santana, the other buck that is over 2 years old, lost his brother back in the summer.  He also is donig fine on his own.  I  thought i would at least let them mingle through the cage bars like I usually do, the cages are across the room from each other.  However, Santana is absolutely ridiculous!  He walks sideways, pressing against Bos cage, urinates on the sides of it, puffs out his fur, hisses and spits if Bo comes near him, and they smack each other through the bars, all the while they are making this odd hissing  sound.  I dont dare bother letting them together. Santana has only one eye, losing the other from a bad infection, and I cant take the chance that they fight and Bo may hurt Santana and possibly hurt his only eye.  Its not worth it....so I give both boys extra attention.  Bo could care less, but I forgive him, hes my old grumpy   grouch, but Santana is my bud, and he is more clingy now than he used to be with me. I love it though so its ok.

I cant tell you to try again in all good consciousness though, but there may be a chance his testosterone levels are still super high. A vet could always do some lab work on him to see whats up. The good news is, he isnt really that aggressive since he is not a biter, he just likes to be the king and thats just how he is. He is one rat that doesnt mind being alone and thats ok too.