Help with (re)introducing degus

[chy]

Hello!
I currently have four female degus: two 3-year-olds (Uno and Smartie) and two 2-year-olds (Kleinsen and Pipi).

I got the younger ones when they were maybe 2 or 3 months old; I don't remember the exact age. My older ones were immediately in love with the smaller ones; the younger ones... not so much.
I kept them in the same cage, but with a mesh divider down the middle to keep them separated. The younger ones were quite aggressive. They were constantly jumping and climbing on the mesh divider and trying to destroy the mesh to get to the other side. After not seeing any improvement with their behavior, I decided to get a separate cage for them. Both of their cages are roughly the same size: 100 cm by 150 cm by 70cm. Both have three levels plus some additional ledges and bridges. The cages are close to each other, but do not touch. This actually did fix their aggression, but only temporarily. Pipi got along with both Uno and Smartie, and Kleinsen got along with Uno but hated Smartie.

As the smaller ones got into puberty, they started being more aggressive again. This was about 2 years ago, so I don't exactly remember the exact details, but I remember Pipi not getting along with Uno anymore, but at that time she was still getting along with Smartie. After some time passed, tension was rising between Pipi and Smartie. Pipi would start chasing Smartie, so I separated the two groups completely. Before that, I let Pipi or Uno switch cages as they desired to bond with the other pair. Looking back, I probably shouldn't have separated them this early  
I was hoping that this was only happening due to puberty. But now, two years later, they are still acting the same. Kleinsen does, surprisingly, still get along with Uno, but it always feels a little tense.

Kleinsen and Pipi are still super aggressive... When letting them free roam, the only thing they try to do is break into the other cage. They will climb up the mesh and try to bite the other degus through it. They also grunt aggressively and bark out of frustration sometimes, because they can't get in. Sometimes they will even attack each other when Smartie is close to the mesh! Uno and Smartie on the other hand, are always trying to greet them with friendly chirping.
I've been letting the pairs switch cages back and forth. I'm not sure if this was a mistake. Both pairs have been using the same sand bath the entire time. No matter what I do, the (one-sided) aggression won't stop. I'm nowhere near letting them meet without a mesh to protect my older ones from injuries.
I don't feel like they have made any progress during the last year, and I'm honestly out of ideas. Seeing all four of them cuddled up together is one of my biggest dreams, but it just seems impossible.
Has anyone ever dealt with introducing aggressive degus? I don't want to give up on them, but I really need advice. Any help is greatly appreciated 

[savvy]

I think you need to go back to the beginning. Swapping cages is really confusing them as they are constantly thinking their territory is being invaded by other degus. Degus are incredibly territorial.

Try keeping them in their own cages, but swap the sand baths and a handful of substrate only between the cages. This will slowly get them used to the idea of each other and give them all the same scent. A pack scent. Keep the cages side by side.

Be prepared for it to take a while, they can be incredibly stubborn and there are no guarantees they will all eventually get along, but introductions need to be done slowly and on their terms. Degus refuse point blank to be rushed.

Keep us posted as to how you're getting on.

[chy]

Feb 4, 2024 20:42:43 GMT savvy said:

I think you need to go back to the beginning. Swapping cages is really confusing them as they are constantly thinking their territory is being invaded by other degus. Degus are incredibly territorial.

Try keeping them in their own cages, but swap the sand baths and a handful of substrate only between the cages. This will slowly get them used to the idea of each other and give them all the same scent. A pack scent. Keep the cages side by side.

Be prepared for it to take a while, they can be incredibly stubborn and there are no guarantees they will all eventually get along, but introductions need to be done slowly and on their terms. Degus refuse point blank to be rushed.

Keep us posted as to how you're getting on.

I will. Thank you for the answer! 

I've been keeping them in their own cages again for roughly 2 weeks now because I realized it's most likely causing a territory issue, just like you mentioned.
What do you think about free roaming, considering the territorial issue? I usually let one pair roam free at a time whenever I'm not too busy. Could this cause aggression as well? Or does anything outside their cage not exactly count as territory? 
I would love to hear your thoughts on this!

[savvy]

Their main territory will be their cages. There shouldn't be too many issues with free roaming as long as you don't let them all out together, but you may need to keep a close watch when they approach the other cage until tempers cool a little.

[chy]

Alright, thank you for the advice! I'll keep you updated if anything changes