Yesterday, I put Augustus back out into his "winter hut" and opened the door. He remained asleep. Today, I opened his door and he had his eyes open, and a little while later, he was in front of his hut. We offered him dandelions which he accepted.
I took him over to the vet and he weighs exactly the same as he did when he went down on September 30th. He might go back to sleep a few more times before 'staying up' all summer. I guess Spring is here!
