After arriving at the Boma after a 90 mins drive. Still keeping an eye on the lions to check they are breathing ok, and also that they were still asleep!! I was in the truck with them doing this for over 2.5 hours in total - and they did start to wake a number of times and required a tranquillizer top up; twice we had to stop the truck so I could drag a lion's head around by it's ear (the only bit I could get a hold of) to move it so it could still breathe. They are very very heavy!