Okay so I just went and bought a digital scale. If the reading is correct, I zeroed it out and then put him on there. it said 192 grams. If a year old ball is suppose to be around 900 or so grams did this person just lie to me about his age or is he THAT under weight?? I also purchased the thermostat suggested earlier in this post and a digital hygrometer...should have both by early next week. so with his weight....any suggestions as to what size rat I should try next. Also he has eaten 4 times for me since I got him.....he hasn't pooped or peed yet (that I can see in his enclosure) should I be concerned?? thanks in advance for any further information and suggestions!