I think it is a ground squirrel - we live in northern Nevada & have a retaining wall made out of rocks. My daughter & I saw it the other night where our grapevine is. Dh set a trap and caught it today & relocated it. Trap is reset to catch it's spouse, siblings, children. Here is the ?ground squirrel? It has a long bushy tail - at least as long as its body. and another It was living in the wall - which also extends to the left - it is about 106 ft long. The grapevine is to the left of the photo - This picture was taken when it was built & the vine was just planted - it now covers half that fence.