Rats are actually very clean and groom themselves constantly! I'd give mine little baths and they'd just sit there all spooked up waiting for it to be over lol
They can also be potty trained though males are easier than females so you better be ok with giant nuts being dragged around your place.
It's a mating strategy as sperm volume increases the rat's chance to reproduce. Single female mates with multiple males and more volume translates into higher chance for male's sperm to succeed.
In general, nut size directly correlates with promiscuity across most species so you can tell how a species fucks just by looking at their balls :D
Nothing that lives in sewage is clean, least not the things that clean themselves with their mouths. What makes something unclean is not dirt, it's the pathogens.
Tbf we think they're gross because they have more resilient digestive systems than us, allowing them to be perfectly fine eating stuff that would instantly cause food poisoning for a human.
Vultures are like that too, stomach acid capable of breaking down neutron star matter!
The only good thing about stink bugs is that they're so slow and easy to catch. If you do it gently you can set them free outside and not have to smell that awful acrid stink.
Mice might be clean in themselves, but they're not in any way trained about toilet habits and they go right where they are, wherever they are, frequently.
You'll know you've got a mouse (or more) because the poops turn up everywhere.
No idea about rats. Never had one as an unwanted house-guest and hope I never do. They're more likely to stand their ground and fight than mice even if their toilet habits turn out to be better.
I assume Liz Climo's characters are better about these sorts of thing, but I can't say I've seen a comic of hers to prove that.
