Moles make holes like that, too Ann. If you have a GoPro, you could set it up at dusk and turn it on for a while to see what shows its face? Mine's programmed so I can turn it on and off from my phone, remotely too.
I didn't know crawdaddies made holes in the garden! Always thought they were purely an aquatic critter. I sure love ATP and all the crazy info you learn here.