Mine used to like pulling apart dried gourds to get at dubias hiding inside, and I used baskets and plastic balls with holes to hide food in as well. In the wild, Savannahs eat large numbers of insects, and have developed powerful jaws and crushing teeth they use to eat even hard shelled things like beetles. These guys get obese extremely easily, so lower fat protein that they need to catch themselves helps keep them healthy. Lean supplemental protein like fish and chicken are good choices too.