Ear biting

[Snakerats]

Hey, very new to owning rats and have already stumbled into a possible problem that I haven't been able to find awnsers for.
I have 3 female rats from the same litter, my biggest, Mamba seems to be biting at my smaller rat Boa. At first I had thought it was a dominance problem, since Mamba is obviously the "alpha" and Boa isn't one to go down without a fight, but now that Boa has torn ear tips it's becoming concerning. It's scaping over and they don't look to be reopened in a few days now, but there's a very notable notch in her ear.
Both of them leave their very friendly and submissive sister Kobra alone so there's no problem there.

Boa is very reserved, she does not like being held or touched too much while Mamba is a cuddle bug, could it have something to do with that? All three of them have more than enough entertainment in the cage and I've started to take them out to explore the room (they still aren't a fan of that but we're working on it) so I don't think it's boredom, but I don't know.

I'd rather not separate or rehome one of them if it can be avoided so any help would be appreciated.

 

[lilspaz68]

is Boa scared of Mamba, stiffens up when she's around or do they end up still sleeping and hanging together the rest of the time?
How long has this been going on now? Mamba may be going through a phase with her hormones which makes her think that the other rats are babies that need to be dragged back to the safety of the nest. They will grab onto fur and on dumbos those big ears are a great handle LOL

 

[Snakerats]

Boa hasn't shown any fear towards Mamba that I've seen of, she was a little standoffish at the start when I first got them but she isn't anymore. They sleep in the same hammock still, but Boa seems to either chosen or has been forced to sleep in the lower part of the hammock away from Kobra and Mamba. I noticed the bite marks about 5 days ago and have been keeping an eye on them, it doesn't look like Boa has gotten new wounds moreso just the scaps falling off and leaning behind torn ears.
Funny enough Boa is the only one that not a dumbo.