I wonder how much his hand rearing helps in his training. They could start training him pretty young as opposed to a mother raised cub who they would have to wait to come out of the den and for mom to let them near keepers for training. It's probably hard for the keepers to guess based on experience since only one cub in the history of the zoo has been parent reared. Hopefully they will get to find out this coming winter when Aurora gives birth yet again to cubs she might actually be able to rear.
