Today after I returned home from work I witnessed my male greek tortoise stick his tail in the cypress mulch substrate of his enclosure and wiggle dig into the substrate with his tail. This is the first time I have ever seen him do this and normally he retracts his tail and keeps it close to his shell. He wasn't making any sounds and other than his tail digging he wasn't really moving much. Is this normal behavior or does anyone know what he was doing?