They do dig a lot, but my little one is often out of it's burrows, looking for food. And MAN can it EAT !! It is about 2.5 inches right now, and although it is fairly well behaved for now, it has reared up and/ or struck more than once. It digs the coolest tunnels/ towers, and frequently renovates it's enclosure. They are also very nice looking IMO. They like it humid, and about 75 + degrees .
I have one that is 2 and half inches. He is really shy and is not really defensive. HE does not burrow insted he makes web tunnels. I ussually don't go in his cage more than once a day. When I firt got him he was very nervous but he tolerates me really well. He is not really skittish but he is very cautious. I think I just got lucky. I'm not sure if its a male of not, but i'm just asumming is a male.
I like to keep the cyanognathus myself. Mine have built really elaborate tunnel systems. And are extremely aggressive (fangs dripping with venom and all). For some reason mine arent really big eaters, but they do eat healthily. Very humid, and VERY gorgeous species. Even prettier when younger. They sort of dull out when older, but in the right light they shine like no other species I've seen