We just got our two male ratties a week ago. We've noticed that Sagan makes a noise that is not a squeak as he sometime makes while playing with his brother. It also doesn't sound like a breathing issue, which is what I was most concerned about, having read so much about respiratory issues that afflict many ratties. I've learned that rats really don't make noises for the exception of when they are in distress or pain etc. We're searching the web for some video to show another rat making a similar sound but we can't seem to. We are new to this and hope that its just a noise he makes when he is content as he seems to be when making the noise. Anyone else have experience with rat noises?