John Ruskin, in teaching people to paint, has described photography as a “supplement to active conscious seeing”. Both painting and photography can be a way of possessing to the world.  If you google the topic of photographing wildlife, you will get a jillion tips and how-to advice, but not the existential reason as to why.  Perhaps it is to preserve the moment (i.e. to document a rare or unusual find).  Perhaps it is to possess the moment in a way that it may not otherwise be preserved within the conscious .  The memories ten years and tens of thousands of miles may be muddled. However, the picture is a moment frozen in time, place, and space which others, if they choose to be voyeurs, can incorporate into their own atavistic memories.