So, my rats are healthy. Very healthy in fact. Smeagol is finally gaining some more weight. He finally learned how to fight back when his brother tried to take his food. Anyway, I just moved them to a much larger cage and they seem to like the amount of space they have now. Anyway, I had the TV off and the apartment was really quiet and I heard this sound that can only be described as sounding like the Cadbury bunny commercials. I went over the cage and looked at them and aside from looking like I just woke them up from a very restful nap, they seemed fine. Except for this sound they were making. I took them both out of the cage and let them climb on me a little bit, and then they went right back into their cage. They had about 6 hours today of running around the apartment. That's what I contribute the lethargy to, but that sound they made made me kind of nervous. My last pair never made that sound. Anyone know what it might be?