My little man passed yesterday and his brother has been alone since I took Peaky to the vets. I am looking into potentially adopting a similar age rescue at some point to pair him up with, but I am not interested in getting a young Degu as a buddy for him, so it may take a while. I've known too many friends cycle small animals like that and I can't bring myself to do it.
Over the last 30 or so hours Blinder has exhibited some odd behaviour.
The most noticeable being the way he acts in his wheel. He makes what is like a barking noise except the squeaks are very long, like opening an old door as he begins to run. Stops the noise and then warbles/chirps to himself as he runs. When he stops to take breaks he either buries his head "down there" and/or wags his tail like a dog. All the while he chirps and warbles loudly. The shriek at the start is very similar tothe sound Peaky made when a squeeky door was opening, hence the comparison.
Another strange and worrying behaviour is that he occasionally climbs to the highest perch and chitters his teeth, almost like he is addressing the room or giving a speech. I know that this behaviour can indicate aggression, which is worrying. It's the same thing they do when they snuggle and get comfortable before sleep.
Final thing, which I have an idea why he is doing but the timing worries me... I've spotted him arch his back high up like a cat, and unsheathe his... yes, and look as though he is cleaning it. I've heard of this behaviour when in season but he is alone right now and there is no competition!
It sounds like Blinder is trying to come to terms with his brother's passing. Degus are very smart animals, so it's very likely he noticed that Peaky was ailing, and now that he's gone, Blinder can likely understand what has happened (or at least understand the important bits). It would make sense that he's agitated and distressed now that he's alone in the cage. It's also very possible that he's also reacting to the change in the social hierarchy of the cage, namely the fact that another male has left. It likely isn't serious as such, unless you notice that he doesn't eat or otherwise isn't performing basic functions, but it will take time for him to come to terms with things.
For now, you should give him time and attention and a lot of cuddles. It's important for him to know that things are still safe and that you are there for him. Something like this can no doubt be very frightening and stressful for a small animal (or any animal), so making sure that he knows he is safe and loved is important.
He definitely knows of Peaky's passing as I placed him in the cage for a while when I came home so Blinder could figure things out. He chirped and inspected Peaky all over (it looked like he was grooming him, or trying to get his attention ) so he definitely had an idea. I didn't want him to feel abandoned by his brother.
As for attention, I haven't left his side since other than to take basic care of myself (which feels like such a chore), his cage is even moved right up against my bed at night now. It's hard to sleep as he's a loud dreamer but it's cute and reassuring to open my eyes and see him on his back, half off the snugglesafe pad and munching on hay while upside down!
Pawing at his mouth could be worrisome. How long ago was the dental operation? It's possible that there's still some soreness from the last one that's bothering him, rather than a new problem.
As for his self-enjoyment situation, it's rather intresting. To me, it sounds like he's kind of realized that he's the top degu now, due to being the only one, and that's causing him to do stuff like that a lot more now.
My male degus did a lot of "enjoying" of themselves. It could be increased due to being alone, but it is a very normal behavior at any time.
As for the pawing at his mouth . . . did he have a dental treatment not so long ago? I have heard of degus (from other members on this forum) needing a dental treatment as often as every three months. When that is happening, there is a question as to whether or not they may have a vitamin D deficiency. Do you feel your degu pellets that have Vit D in the ingredients?
1 Bichon/Shi-t-zu Ollie (b'gollie), 1 Standard poodle, Indie
I'm terribly sorry to hear your news, I hope you are doing well.
This is a bit of a side note. I hope your boy is OK, and he doesn't have any dental issues that are causing him any problems.
Just so you are aware, there are 2 lone degus with the RSPCA right now, one is called Rick, and the other is called Morty. But most importantly is things go smooth for you now, and you and your boy do well in the coming weeks.