Thread: What could be making this scraping sound behind the ceiling vent?

So today around 5am, I started hearing scraping sounds exactly behind the ceiling vent between the living room and kitchen. It was kinda scary. Even my cat woke up and ran to the spot and looked up. It went on for a few minutes and stopped. I am on the 2nd floor, and there's another floor above me. What could be going on? I'll need to wait to see if it repeats (heard this the second time so far in 2 days) and at what times. Any ideas what it could be.. maybe I'll need to call the maintenance person. It was almost as if there was something/someone there making those long scraping sounds (they are hard to describe). What's usually between 2 floors? Thanks guys. I hope it doesn't repeat again because it was scary.

Rodents.