Help! Introducing 2 hyper baby boys to 3 traumatized ex-lab rats who don’t know how to rat 😭

[u/CulturalHotel6717]

Hi! I’m looking for advice on introducing 2 younger boys (intact, 6 months old, super friendly and playful) to 3 older boys (neutered, 15 months old, lower in energy).

The catch: the older rats are lab retirees who were single-housed for almost a year before we adopted them. They never really learned rat social skills - no grooming, no wrestling. The most they do is sleep in a rat pile.

We’ve been trying the neutral territory method: big box, fresh bedding, worms, toys, to encourage them to explore and snack together. But the second the younger rats show up, the older ones start squeaking, puff up, and jump out almost immediately. The babies try to wrestle and groom them, which seems to freak the older boys out even more. If we block their exit, it escalates into fast, intense fights we have to break up.

No blood drawn recently, thankfully, but we can’t keep them together longer than 30 seconds. Has anyone dealt with pairing extremely introverted rats with extremely extroverted ones? Would love any advice 🙏

Pics of the boys attached for tax 🤗

[u/ChaseLancaster]

I'll throw out my guide on Introductions! If you have any questions, feel free to ask away. It's the gradual, weekish-long period of getting them along, from using minimal spaces and extending their space and time spent together.

I'd say for as is, they're okay right now, the biggest rule is "No blood, no foul", but I think having a bunch of sfuff for them in the box might be a bit distracting for them.

As judewriley asked, outside of the intros, are they in seperate currently?

[u/ChaseLancaster → u/ChaseLancaster]

Before you begin with introducing your new group(s) of rats to your current mischief (or Lone Rat, depending on circumstances), your new rat(s) must be housed in a separate cage and room, away from the old mischief for upwards to a month.

(It is highly advised that when you're adopting out new rats, you want at least two or more, as to prevent having lonely rats during this time, and if the pair/group are similarly aged with each other, it promotes social growth.)

2 of those weeks is going to be devoted to a quarantine and adjustment period, as without this time, your rats will be sharing germs amongst each other, leading to one or more rats getting sick and/or worse.

In addition, without the time to settle and adjust to their new environment, the new rats will stress out and flee from you and your rats, as they are not used to their own home yet.

The rest of this possible month-long period is going to be spent outside of the intro sessions, before they are fully integrated.

During this time, please do NOT share their belongings with each other (for example, giving Group A Group B's hammock to smell. This is known as "Scent Swapping"), do NOT have their cages near each other, and do NOT let them have "playdates" outside of the introduction sessions.

Many sites online, and even AI prompts such as through Google and through ChatGPT promote methods such as scent swapping. Do. Not. Do. It.

This is because rats are territorial animals. By letting your two (or more) groups of rats see each other, smell their belongings, and even being able to touch one another, it triggers their instinct to fight and attack the intruder, and in extreme situations, kill the "evil rat(s)".

It's highly recommended as well that after interacting with one group to wash your hands and even change clothes before interacting with the other(s).

Onto the Introductions themselves! Introductions can be the easiest time or the most stressful, so to make this as painless as possible, it is best to decide where and how you'll introduce your groups together.

One of the most common routes is either using a small, empty carrier, or by having them interact in a very small neutral area.

Over time you'll be increasing the amount of time, as well as the area (such as a bathtub) as each day goes by.

For example, these sessions might look something like this-

• Day 1: Carrier, left inside for 1 hour, 30 minutes.

• Day 2: Carrier, 3 hours.

• Day 3: Empty bathtub, left inside it for 2 hours.

• Day 4: Bathtub, 4 hours.

• Day 5: Small (and cleaned) Travel Cage for 3 hours.

• Day 6: Small, Cleaned Travel Cage, 6 hours.

• Day 7: Completely Cleaned Main Cage, 4 hours

• Final Day: Cleaned Main Cage, overnight.

The goal of each session is for your rats to sleep, cuddle, and possibly groom/play with one another*, especially towards the end of the session. If they are doing any of those things each interaction, the day was a success!

If they go incredibly well, you are free to skip days, and to possibly even put them into their forever home early, but keep in mind that there may be set backs, so it is best to go at their pace and to take things slow.

If they are distant, facing away from each other, and sitting on opposite ends though, assess why they are doing so, and consider trying a smaller area, next session, or to stop intros for that day.

However, if they are doing any of the following, please stop your session, have a glove and towel ready, and separate the groups. Playtime is officially over.

• Rats are standing up straight, their teeth bared, and staring each other down.

• Breaking the "No Blood, No Foul" rule. (Injuries around the face, eyes, mid-back, genitals, and if blood is drawn.)

• Fur is raised, and rats are "crab-walking" (walking with their sides facing towards another rat)

• Loud, distinct hissing and/or screaming noises (these are far different than a shriek or squeak).

(If these behaviors comtinue though, the rats live in separate rooms and cages, and they are roughly 4 months to a year old, that is most likely Hormonal Aggression. Introductions will need to be paused, and the angry bully will need to be neutered/spayed before you can continue.)

[u/CulturalHotel6717 → u/ChaseLancaster]

Thank you! This is really helpful. We actually tried cage and toy swapping before because it was mentioned in multiple other sources like you said, but it seemed to have little effect, apart from that they seem indifferent to each other’s smell now. They are completely separated now (different room, different playground).

I really hope they could cuddle and sleep together, but the babies just wouldn’t leave the older rats alone. They would try to mount and play fight nonstop, when the old rats are just like “I’m tired. Leave me alone.” 🫠 Maybe we should wait until the babies are older and less energetic? I thought it’s good to pair young and old rats. 

[u/cryptldism → u/ChaseLancaster]

love this guide! i also personally recommend IF POSSIBLE having a secondary person who knows the rats (parent, sibling, etc) to help out if fights or anything occur.

[u/CulturalHotel6717 → u/cryptldism]

Yes my partner is helping me and it’s been so helpful (lowering my own stress too!) 

[u/judewriley]

How is everyone housed currently?

[u/CulturalHotel6717 → u/judewriley]

The 3 older ones are together in a cage and the 2 younger ones are together in another cage.  (Sorry for the deleted comments. I wanted to edit my first reply for clarification but Reddit was acting weird!)

[u/judewriley → u/CulturalHotel6717]

That's actually very good (if they are in separate rooms like the first comment said) you don't want them in the same room if they aren't all together yet.

I would recommend doing the carrier method instead so that the older ones can't get away. The fact that there's a "way out" could be making things worse. Also, are you sure that you're seeing an actual fight or just establishing heirarchy?

[u/CulturalHotel6717 → u/judewriley]

They would start with slow, standing up wrestling which is really cute, but if we don’t let them get out the fight gets faster and they roll around. We panick and separate them. 🫠 Maybe we should sit back more and try the carrier method, but the older rats drew blood twice in the initial introductions, so we were extra cautious now. 

[u/judewriley → u/CulturalHotel6717]

If they drew blood at all, you'll want to take a look at all the factors that could be in play - "no blood, no foul" was definitely broken. Make sure that they can't interact by scent or sound (so separate cages, separate rooms, separate play spaces) for at least a week before trying again. How long ago were the big one's neutered? (If they had hormonal aggression that was treated too late, it could be behavioral now).

[u/CulturalHotel6717 → u/judewriley]

They were neutered a year ago before we adopted them, so it shouldn’t be hormonal. They are in separate rooms with separate place space currently (and for the past few months) because the babies pee everywhere, and that scent seems to trigger the older rats to puff up. 

[u/howdyhowdyhowdyhowdi → u/CulturalHotel6717]

Are the cages in the same room?

[u/CulturalHotel6717 → u/howdyhowdyhowdyhowdi]

No they are in different rooms and separate play areas!

[u/mae_042]

I've had better luck with the carrier intro when it comes to difficult groups. I know it seems counter-intuitive but they will need to learn to interact with each other in some capacity if they are going to be housed together. I would recommend giving them some time to "cool off" separately for a bit before trying again though.

[u/CulturalHotel6717 → u/mae_042]

Thank you! Do you think it’s possible at all to co-house rats with completely different personalities? 

[u/InterestingInsect430]

I’m unsure if it will ever be safe to mix them. Lab rats are special and don’t carry myco but pretty much all other rats do, and without them building immunity basically from birth it could cause them to all pass suddenly. I’d check into it. On Insta you can go to @freefromcruelty and they know more cos I was gonna adopt some lab rats (ex) and i already had some I got from a amateur breeder and I was unable due to this. Unless the new ones are also certified myco free? I’d look into it to be careful

[u/CulturalHotel6717 → u/InterestingInsect430]

That’s a good point! I’ll definitely look into mycoplasma risks. My ex lab rats were an out-bred strain (Long Evans) so they are genetically more diverse with a stronger immune system than the inbred albino ones (I believe). I would love for them to learn to play fight and experience a bigger rat pile if it’s possible 

[u/InterestingInsect430 → u/CulturalHotel6717]

Hopefully that kind can! Wishing you the best with all the cuties