Extreme Aggressiveness in Female Breeder Rat

[frankykeno]

Just looking for some input here from you rat breeders. We have a female rat that's been raised with us (not a new purchase). She was always a bit nippy but suddenly she's become impossible. She's on her 2nd litter which are currently pup sized (just shy of weaning age).

She became very aggressive with us when she was in with the breeder male and even more so as her pregnancy progressed and after the litter was born. To the point of extremely hard bites for both Mike and I. She has to be physically blocked from getting to us when we feed or water her. This I could deal with however she's now turned that aggressiveness on her own litter.

She's killing them, one every few days! I kept finding a dead pup but not a mark on it and wondered if they were genetically inferior pups. I finally caught her at it last night. She had a perfectly healthy pup in her mouth by it's hip area and was flinging and shaking it, even almost cartwheeling with it in her mouth! I've never in my life seen such behaviour from a female rat. It was highly disturbing to me and I've removed the remainder of her litter to another female who is nursing and has accepted the foster pups.

We will euthanize this female today as I can't have her killing healthy pups plus I like to breed calm, good natured adults. I've just never seen a female turn like this for no reason at all. Nothing has changed in her daily routine, feeding, etc. This was not a particularily big litter to stress her out. I'm just stumped as to why she'd go from a sort of grumpy rat to this horrible aggressiveness to us and her own pups.

[Pork Chops N' Corn Bread]

Hmmmm. Wierd. About how old is she? Sometimes when they aren't lactating enough, due to a large litter(likely not your problem) or age, they will kill their babies off. I wouldn't know why she is acting like that though. Any rat or mouse I buy and it bites me is instant snake food!!! How many litters has she had? Maybe shes just on the end of her breeding life.
Have you introduced any new rats to her? She may just not feel safe and thats why shes killing them

[Smulkin]

Jo we too have had a couple who eventually just seemed to go off the deep end despite the same uniform care and conditions afforded the rest of the rats - and all the other mommies are almost congenial. The last couple times it happened seemed to mirror your experience - a partition would have to be used just to be able to reach in the cage. In both instances after noticing she was destoying her litter we broke down and redistributed them to other moms who had babies of the same size. The seem to be rally great about being universal moms - regarless of genetic parentage.

I am not sure what was at the root - in both instances (coincidence I am sure but they were both albinos) they became food. I have seen the mothers who did not exhibit pregnancy rop litters while still int he cage with a male - and know the males attempts to mate can set the mothers into a defensive frenzy - but in these couple of cases where they are in their own cage with their litter and nothing else I am not sure what to make of it.

[frankykeno]

I haven't a clue what's turned this slightly nippy rat so dangerously mean but irregardless she's being put down humanely today. It's not fair to her pups, dangerous to the kids if they are helping feed the rat colony and in the end not much fun for this rat as she'd have to be kept away from the rest of the colony the rest of her life. She can't even retire to pet status as the other breeders do here when their breeding cycles are done. A quick end is better for all concerned.

As to issues....she's treated wonderfully as our all our breeders, not stressed with back to back breeding, in the prime of her breeding life and in perfect condition, her litter wasn't all that large and it was her second so there is no reason I can see for her going rogue like this. Guess it just happens sometimes.

[JLC]

I wonder if rats can suffer from post-partum depression? Some sort of hormonal/chemical imbalance that was triggered by the most recent pregnancy?

[frankykeno]

Hard to say Judy. It may be hormonal as she began to show real aggression during the breeding cycle for this litter and has just gotten progressively worse. From what a few other rat breeders have said though, she's likely to never be trustworthy again with her litters or even other rats let alone around us or the kids. Apparently once they go mean like this they rarely go back to a more normal rat personality and I hate to see healthy rat pups destroyed like that by their own dam.

She actually didn't start destroying her young until we figured out how to block her from biting us. It's like she's taking out this unnatural instinct to hurt us on her own litter. Just very odd behaviour. Glad I don't see this in my colony normally and I certainly won't use any of her young as future breeders just in case.

[Pork Chops N' Corn Bread]

I wish you luck Joanna. If I were closer I could pick up your huge retired breeders for boa food!!!
I hope this doesn't happen to you again
Good luck

[Jeanne]

Jo, as I said on the phone, you are making the right choice to euthanize her. IME, once a rat goes rogue, you cannot use them for breeding b/c they will continue to kill thier young. And, you cannot use them as pets, b/c they will continue to bite the crud out of you.

[Pork Chops N' Corn Bread]

Good reasoning Jeanne!! How exactually does this happen to a rat? Haven't heard many cases of rats going rogue

[Jeanne]

Good reasoning Jeanne!! How exactually does this happen to a rat? Haven't heard many cases of rats going rogue

Its really not known why this happens, just that it does happen from time to time even with the best of care given.

Find a talking mean rogue rat, and ask it, and then we would know..