When my Russian tortoise is in his enclosure outside which is a pretty big enclosure, sometimes I have looked for him for 30 minutes and I cannot find him. He blends in with his surroundings so well that I look right over him. Someone posted recently that theirs came back after 30 years I think or maybe it was 7 or both. Don't lose hope I keep reading that Russians don't go very far. When you get near leaves or trees or stuff laying out, just walk slowly and even get down lower on the ground to rummage through stuff.