Forgot to put fish food away & saw this in a.m. I'm thinking it was a possum or maybe raccoon? You can see some claw marks at left (red lines). Would be nice if they would just take lid off! Did a squirrel do this or something bigger? Can on left is 5" & claw marks are 3/4".

Rats could also do that, and most likely will make a hole.

The raccoons are too intelligent, they will simply remove the covers.

I never saw a rat around here, but that is a scary thought! I am 1 block up a big hill from the Milwaukee river though, Please, anything but a RAT!