What do you do with a dead rat?

My rat died at 3:00am today, and I had no idea what to do with it. My mom buried it in the garden near our plants, but I'm not sure if that is going to effect the plants or not. She was getting pretty old, her whiskers were all white. Was it a good idea to bury it in the garden? Or what else should we do? Oh, and she was breathing pretty hard before she died.