Here in NY the weather is in the 60's this week and today it was 68. Two weeks ago we had snow. The day before the snow, they all dug down to hibernate. Yesterday one came up and I saw him sitting in the pond. He went back under and I haven't seen any today at all. I really don't know anything about artificial hibernation. But seeing any come up on a warm day is not unusual. I really don't weigh mine, so I can't help you with that either.