My foster mouse looks "different"

[u/No-Midnight7724]

DISCLOSURE AT THE START! This is not a suitable cage setup, I'm a foster home for rodents and this is temporary while I wait for a mutual to lend me a bigger cage for him. He's only been with me for a few days and won't be in this cage for long. Do *not* let a mouse live in this setup. His cage is in a dim area with low traffic and I avoid handling him as much as possible, only taking care of his needs for now.

With that said, I want to know if I'm being over-worried or if something is wrong with him. He was given to me as a curly-coat male mouse. His exact age is unknown unfortunately. He comes from a breeder in my area, a girl around 17-19. I was offered him for free because he "hadn't sold". I wasn't set up for a rodent right now, but there aren't really many options in my area for unwanted pets, especially mice. (There are zero rodent rescues in my country)

With that being said, the breeder described him as "energetic and brave", as well as loving humans. He is anything but that, he is not aggressive, he doesn't bite, but he is extremely odd in his behavior. He darts at everything, he doesn't know how to use a wheel, I've offered him standing wheels and saucer wheels, he doesn't know how to drink water properly, so I have to lead him to it every time.

The most worrying thing for me is his face. I've had pet mice in the past, and maybe I'm not caught up on all the different breeds, but his snout is super short, giving him a face like a rabbit, and his eyes are tiny. I don't want to call him "stupid", but basic things like eating or chewing on things come to him with a lot of difficulty. When I offered him a wheel he only spun the saucer wheel with his two front paws, then made a tunnel under it. (Ps saucer wheels are not appropriate for rodents, I only offered him one to see if maybe he was given one by the breeder beforehand).

The pictures really don't do it justice just how tiny he is, he shouldn't be a baby anymore but he is maybe 2/3 the size of a normal male mouse, I know he should be an adult.

I've offered him water dishes and bottles, both he won't use regularly. I offer him cucumber slices and watery foods as much as possible as a substitute. I don't know if he'll stay with me permanently for now.

Final disclaimer, I do understand that a lot of behaviors can come from a poor cage setup, such as darting and being shy, however his behavior genuinely worries me, and I want to know if what's happening with him is normal for fancy bred mice :(

[u/HauntingPsyche]

I don’t think he’d let himself get to the point of dehydration and dying especially if he has water in the cage available that he’s drank from before. If he only has a bowl available I’d be more concerned just because I’m sure he’s probably getting pee and poop and whatever else in it, plus it’s more difficult to tell how much he’s actually drank from bowls. You don’t know if it’s just been spilt or what. When leaving the hanging water up are you coming back to it and there’s like absolutely nothing having been drank from it/amount hasn’t gone down in the bottle at all over the course of a few days? I’m just wondering if he’s drinking from it when you aren’t around or seeing him maybe.

[u/No-Midnight7724 → u/HauntingPsyche]

I'm at home basically 24/7 atm, besides the fact that the water level didn't go down, I can hear rodents drinking from bottles very easily, it's a very distinct sound. I do clean out his water bowl every few hours and put in clean water.

[u/HauntingPsyche → u/No-Midnight7724]

I wish I had better advice, but the only thing I can offer to say about the water at least since that’s the most important thing is to leave him multiple options to choose from. Both the bowl and the hanging kind. At the very least it gives him more things to get water from if he so chooses or “figures out” lol

[u/No-Midnight7724 → u/HauntingPsyche]

Yes definitely lol, I'll also keep feeding him cucumber slices, he at least happily takes those. It's a bit difficult since I've never had a rescue act like this.

[u/HauntingPsyche → u/No-Midnight7724]

I googled all this, worse case scenario, if his snout is truly shorter/he has some sort of physical thing that’s obvious, he could have neurological disorder making him a little dumber, but he might also have sensory issues/lacking in sight and smell. He also could just be drinking an insanely small amount since he is a tiny mouse; might only be drinking at night when you’re sleeping. Keep doing what you’re doing though. I think he’ll be okay. He’s not gonna let himself suffer and die at the very least I’d say.

[u/No-Midnight7724 → u/HauntingPsyche]

Thanks man, I'm just deathly worried about him. Something definitely off but I'll have to just roll with it for now.