This trap is better suited for smaller mammals as listed; I purchased to trap nutria that have infested farm ponds, but I didn't realize how big the nutria were and under-sized the trap. While I'm confident this is an excellent trap for squirrels, gophers or even small muskrat, a 30lb Nutria can escape this trap.
I would recommend sizing the trap up to catch nutria. I highly recomment the #1.75 coil spring offset trap. It can catch large nutria and hold them. Also, action worked fine submerged under water.