He owns the rights to the pictures he takes. No purchase necessary. Especially in the context of wildlife, there are no human subjects to cloud the issue.
My guess was the same as the parent poster's -- the pictures of the monkey grabbing the phone, from the phone's point of view, belonged to the tourist, right? Because the phone belonged to the tourist? The photographer must have acquired those rights afterwards. (Although I don't recall the outcome of the copyright case of the monkey that took its own photograph back in 2014...)
And for me, part of a long list of reasons I will never be in favor of copyright (unless turned back on itself, as the GPL or other free licenses allow).
That concerned pictures taken by the monkey. This is pictures taken by a photographer, with his own camera, by his own will. Nothing remotely disputable.