my only experience with rats...
between freshman and sophomore year, my college roommate dumped her boyfriend and got a pair of rats, which we both agreed was a big improvement. unfortunately, she had asked the pet store for two female rats and when she got home and opened the box, she discovered that one of her "females" had boy parts. suffice it to say, she arrived back at school with a cage full of rat babies.
the mother rat, bella, was freaking vicious and we pretty much hated her (took good care of her anyway, ofc) but all the other rats were sweet as can be. they'd sit on your hand and wrap their tail around your wrist and it was super cute.
the funniest rat moment was when my roommate got a new boyfriend and they, uh, hooked up in our dorm room. I came home at like 6 am and looked in the cage with bella and her babies and there's a pair of pink panties IN the rat cage. I was like "hey roomie, why do the rats have your underwear??" lol. apparently they got tossed on top of the cage and the mother rat took the time to tug them completely through the bars and add them to the nest.