Whatever it is it sounds big. I don't think it's a squirrel they're not active at night. It could be a mouse but it sure sounds bigger than one. Sounds like it's hanging out by the air conditioning system. I've tried to lay traps last year which didn't do shit but I didn't lay them over where I've heard the noise. There's no real walk space in the attic, there's only trusses and it's super cramped. I wonder if it would be worth getting some sort of poison. It gets so hot up there that if something died from poison it probably would be mummified within a day or two although I could be wrong. How do you guys deal with attic rodents?