I think that is just a young tort trying new things. Sometimes they are just really curious and will try about anything.

Just make sure you have a cuttlebone in his enclosure and that should ensure he gets all the calscium he needs. Other than that, just keep up with the various hay grasses (like timothy, orchard grass, but NO alphalpha).

Access to fresh water and occassional soakings would be good too.

Nice looking tort by the way. Good sized already for sucn a young one. My little guys is supposed to be almost 3yrs old and he's still only 4-5 inches. But he had back care before me.