Pet rat's companion died and was cannibalized, she is now alone

Question

About 4 months ago I bought two young-ish female rats, Star and Blaze. The store said they were the same litter, but their coloring and size as they grew leads me to believe that may not have been the case.

Blaze has always wanted to crawl rather than just be held, but licks people and I reward her with unsalted sunflower seeds (her favorite) and has never used her teeth on anyone. Star however, while most of her time with me had been sweet despite the lack of kisses, had always been very cuddly; but she bit someone's ear while they were cuddling her against their neck earlier this month. I was shocked because it wasn't an aggressive "I'm scared bite", but she rather just put her teeth on him and slowly clamped down and wouldn't let go until I pried her mouth open at the jaw. Moments before the incident, she was making a chickering noise often associated with happiness and comfort at her surroundings.

Blaze and Star had lived in harmony for the past 4 months for the most part, other than wrestling that didn't seem to be violent other than a few squeaks. I never even seen missing fur on her like I've seen on one rat that was a bit "bullied," when I had five rats at once several years ago.

At 7am this morning all seemed fine, both just waking up and being seemingly energetic and healthy... but when I came back from work at 5:30pm, Star was dead and Blaze was eating her! I know disposing of a body by eating it is completely normal for rats and other small mammals as it's the only way they know how to get rid of the body, regardless of how traumatizing for me it was to witness.

One of my concerns is that many times their wrestling was not long after I fed them (a bowl full every other day) and Blaze was definitely bigger in general either because of them being a different litter like I suspect or her dominance over the cage and the food. I'm worried that Blaze may have killed her either over a food scuffle, by accident or if Star passed for some unrelated reason. With knowing now that she can eat her cage sister, while I don't want her to be lonely, I'm concerned of her taking to a new companion AND that new Rat's safety.

It's hard for me to look at/handle Blaze now, knowing that the insides of her sister are currently in her belly despite how affectionate she's been to me and others in the past... And while I want to leave her be to process the death and for me to get over what I saw, I know rats don't do well alone, especially if they have never been alone before. I don't want to harm Blaze's psyche by leaving her alone in her cage, but I'm scared to witness what I saw earlier again if I get her a new mate.

Does anyone have any advice on:

1. How Star may have died suddenly after having no apparent health issues hours earlier?
2. Is the wrestling I saw normal, or should I have been concerned at the difference in size and the squeaking?
3. If I should get Blaze a new companion, and how long should I wait if I wait at all?

I'd really appreciate any help I can get with this because, despite what happened and how hesitant I am with her right now, I love Blaze and I want to do what's right for her as well as myself. Thanks in advance!

Answer 1

First of all - you're right, this is 100% normal behavior. Blaze didn't enjoy it, but she was simply following her instincts. In fact, it would be more surprising to find a deceased rat that hadn't been eaten, unfortunately.

1) Rats can die suddenly for a myriad of reasons. As prey animals, they are extremely skilled at hiding any injuries or illness, which in the wild would be signs of weakness. She could have had an underlying illness. An internal abcess or cyst that burst. A fast growing tumor (yes, unfortunately, they can grow that fast). A stroke, seizures, megacolon, heart attack... Don't feel guilty that you missed the signs, it honestly happens so often, they're such secretive creatures. Only a vet autopsy would be able to give you a definite answer.

2) Wrestling is completely normal - it's how they show dominance, and how they maintain dominance. The squeaking was Star's way of crying uncle. It's also how they play, like rough toddlers. If there is no blood, no cuts or scratches, then everything was perfectly normal. There was nothing aggressive in their relationship. Blaze didn't kill her sister, especially given the lack of defensive wounds on her. Rats are tough little things.

Also, their shuffles after feeding could be helped by feeding them at least once a day. Every other day is not enough unfortunately. They eat a lot, and even if there is still food left in their bowl, it's likely because those are their least favourite pieces. They need regular feeding, daily fruits and vegetables, occasional treats, and most importantly variety in their diet.

3) Yes, you should get her a new companion as soon as possible. Preferably two younger rats; in trios they are less likely to 'pick on' one particular rat, but also because Blaze will inevitably pass away, likely before your new rat, and you don't want your new girl to be left alone. Don't worry about her being aggressive towards the new rat(s), as long as you do introductions correctly (slow, careful, supervised, outside the cage first, etc) they will get along swimmingly. Just watch for bullying behavior, but this is true for all rat introductions.

Good luck, and please don't feel differently towards Blaze now. She was protecting your territory, and she misses Star just as much as you do.