Hi! My rat Bullwinkle is all of a sudden drinking a ton of water. He's about 9 months old. For 2 or 3 weeks, he's started drinking about twice as much water as he used to. I'm not sure if he's just still growing, or if something could be wrong that would make him extremley thirsty. I haven't been feeding him anything different, or made any other changes. Does anyone have any suggestions?