Also, even if they are in the shade the ambient shade temps get sky high in the summer. And very humid, too. May still be too hot for them further into the summer (it's best to keep them under 80, think they stop breeding at 90? though - or so I have been told - havent actually put that theory to the test). My a/c broke jsut recently so my room has been up aorund 86 or so, my rats are in the basemnt so they dont get the higher temps, but I have one pet rat in my room (and even my egyptian spiny mice) are sprawled out on their backs and sides from that level of heat. I keep thinking the rat is dead when I look over at him
So really they are not very tolerant of excessive heat IMO.