Cuttlefish bone is a natural source of calcium and other minerals. Bio Calcium Sepia Bone are full bones which are excellent for birds, lizards, tortoises and turtles will also actively chew on the cuttlefish bone. As with birds the "beak" of tortoises will be weared away while chewing on the bone. This prevents the beak from developing itself to unnatural sizes which is unfortunately fairly common with captive tortoises. Bulk package also includes broken bones.