In specific relation to this story, Hemingway was a huge adventurer going on several "big game" safaris in Africa.  He would have been very accurately acquainted with the types of characters he depicts in this story, most specifically Wilson.  Wilson is the fountain of all knowledge when it comes to keeping the hunter safe from the dangerous animals they were hunting, and how to ultimately be successful in the hunt to bring down the amazing lions and tigers and other exotic animals.  Wilson is always sharing details about the sights and sounds of the jungle and what they reveal about the animals that Macomber and he are hunting.  He tells Macomber where to aim and when to shoot.  He seems to be the kind of macho-man that Hemingway himself seemed to admire.  Hemingway's heroes are always held to a standard that Hemingway seemed to set for them.  Some critics call this the Hemingway Code (hero).  Men that live up to the code have the ability to "go it alone" and have "grace under fire."  Both of these qualities are seen in Wilson, and only at the very end are they seen in Macomber.  Those are the two qualities that will make a man most able to survive in the world created by Hemingway.