Although I don't participate in it much, I'm part of the Yahoo (and Facebook) group RatsPacNW. It's a place for rat lovers to come together talk about how awesome rats are and to look for solutions to problems. Sometimes what I hear can be quite heart warming, and pleasantly surprisng.
A few months ago one experienced rat lover shared that she had just adopted two rats from a shelter, and that they were both biters. She made a video on her second day after bringing them home, where she shared their individual temperaments and how she worked with them. Her goal was to turn them into lovable pets that could be placed with her other rats and each other.
One step towards that goal was to have them neutered (yes, rats can be spayed and neutered!) but that wouldn't happen for two more weeks. In the meantime they were in separate cages by themselves, and she was working with them to try to encourage them to play nice with her.
Yes, she does make a mistake and gets bitten in the above video. It turns out that you need to keep your palm away from an irritable rat!
Both they both allowed themselves to be petted some.
There have been several videos to share their progress over the weeks, but this is the latest one.
I am very impressed. These two went from biting the hand that fed them to being happy pets. They now get along with each other and they live with other rats without making a fuss. This is pretty amazing. I'd had no idea that a neutering and some loving patience (from someone who is experienced working with rats!) could make such a change.