I have young Russian tortoise, around 9 months old. I noticed he doesn’t stay up for very long and will usually dig a hole and go to sleep after only being awake for a few hours. Is this normal? Sometimes he’ll stay up for around 7 hours, but today he went to sleep after only being awake for about 5 hours. He’s pretty active when he is awake and all eats all his food. He overall seems fine and healthy. I just concerned about him sleeping so much. Is this a circadian rhythm issue perhaps? Should I put his lights on earlier, they come on around 5:30 early morning