@mhardy6647
We have a local rodent that I call Sage Rats. AKA,.. Beecheys Marmot; Cal Ground Squirrel. They are cousin relatives of the Groundhog, and slightly larger than the average tree squirrel.
They are incredibly destructive tunnel diggers.
In one instance, they dug into a slope in front of my house; the leading edge of the lot grading. The builder pushed soil out to an edge, and that created a slope out front. The whole area is covered in 3/4" crushed rock, gravel.
The Sage Rats dug into the face of that slope, below a native shrub, about 2' below the graded dead-level edge. They went back likely further than 10' (house to edge of graded slope is perhaps 20'), and 10' wide.
I found this out by backing my 3/4ton truck onto this graveled area, with a heavy load of gravel. When I crossed their den, it collapsed, and I sunk up to the pumpkin of my rear differential/axle. And it was with both wheels.
I had to break out my highlift farm jack, which fits into the tow hitch. I lifted the truck, and had to start using the load of gravel to fill in below the lifted axle, in order to finally drive out of this stuck situation.
It took a few loads of fill soil in order to fill the void. And its still trying to sink out even now, a few years later.