I believe it’s a pocket gopher. If you look at the photo you can see roughly two lobes that make a heart shape. The top of the heart, the cleavage is at about 4-4:30 of the pile. The hole is under that part of the pile. Each lobe is made from either leg kicking soil out of the hole.
Most often the hole will branch out into a corridor, so you’ll have two holes.
Gotta dig down to those and trap each side. I wire all my traps in pairs and then just wrap it around a stake mid point of the wire to hold it.
I probe the ground to find the direction of the tunnel and use a large serving spoon to dig out the exit hole in the mound until finding the tunnel.
The secret to use the gophinator for me anyway is to enlarge the exit hole to twice the diameter so the gopher has to push a whole lot of dirt to fill it. I put the trap just under the surface into the enlarged hole with a wire attached to a substantial stake. After catching one, just pull it out, and backfilll the hole with the dirt mound the dirt the gopher already has on the ground. Much less damage to the lawn vs digging a hole and using two traps.
I’m 100% on this method. Don’t have a count but I’ve trapped one a week or more for 30 years we lived here.
I use a wire and substantial stake because coyotes cruise our yard and if they cross a trap location, they dig it out and have dinner.