This is possible because he introduced himself to the pride over a period of time. Were he to try this with an unfamiliar pride, the outcome would not be so cute.
For those fascinated with this sort of thing, I recommend a book called "Cry of the Kalihari." It is about a husband/wife reserach team who lived in the bush around the Kalahari Desert. The Kalahari is mostly in Botswana, but has parts in Nambia and South Africa too.
Mark and Delia Owens had sort of a "truce" with a couple of prides of lions in their main research area. They didn't interact with the lions quite this way, but the animals did wander around their camp at times.
That said, Delia Ownes was stalked and nearly killed by a female lion while out of her land rover one day. She was clearing a landing strip for the Cessna that Mark Owens was flying and she got too far away from the vehicle. An unfamiliar pride was in the nearby grass "hanging out," and one of the lionesses began to stalk her. From there it became a staring match as Delia tried to make it back to the Rover, before the lioness made her final dash.
When I was a teenager I would have tried anything. Sky diving, bungee jumping, whatever. I guess you have something to prove to yourself or the world or whatever. Now I think about skydiving and say "Why the heck would I want to put my self in that kind of a situation??" There is no appeal.
When I watch this guy I feel the same way. How bad would his life be if he had children and hung out with them instead? I just can't make sense out of risking your life for no reason.
Note to self:
Move "Animal Behaviorist" down the list of desirable occupations.
Note to self:
Move "Animal Behaviorist" down the list of desirable occupations.