A big part the game is taming so I would count that as in-game hours. If you don't agree then just gather or something as you are taming. That is moving.
I lost a lot of my tamed dinos too. It is not too fun. I try now not to get close to them. All you need to plan proper. I lost enough dinos to know what they can take. So I don't loose my dinos now. I got 953 hours in the game now.
I made this post to see how many hours different people has in the game. Thought it would be fun to see the different hours people played. I have over 750 hours. What do you have?