One thing I have learned is that rats sold as pets have actually been bred over quite a few years so that their traits are quite different from their counterparts in the wild and from the stock they originally started out from.
They have been groomed up to be a suitable pet for humans. They have lost the aggression of a wild rat and are clean, quite intelligent, and loyal to their owners much like a dog. I'm still not sure that a rat is very high up on my list of future pets but I have more understanding as to why people get interested in them as pets. They certainly are more portable than a cat or a dog if you like to take your pet everywhere with you and I have met quite a few young people who do just that.
I also have a series of rat designs in sterling silver, including a pin, two different sizes of pendants, a pair of earrings and a charm. So there is no dearth of designs for my rat loving customers.
But perhaps you just need an inexpensive pewter rat lapel pin to dress up an outfit or possibly to horrify your friends. (It would not horrify me- I think rats are very smart and interesting animals.)