Extra docile young rat

Question
I bought a male rat just over a week ago, and he has settled in with my other rat in the same cage who ive had for longer. But whenever we take him out of the cage to play he just slinks into a warm space and lies there for ages. He isn't lively and doesn't run around and excersise. His coat is shiney, hes eating and drinking okay... Is there anything wrong?
Thanks,
Jess

Answer
I would say unless he has some other symptom to indicate an illness, he's probably just a very lazy, mellow sort of individual.. I wouldn't worry unless he starts acting sick or displays some sort of symptom like poor coat quality, cloudy eyes, rasping/wheezing, coughing/sneezing, respiratory problems or lethargy. Keep an eye on him! :) Good luck.