This film, a notable box-office flop, is generally said to have finished Nicholas Ray's career in Hollywood. He made only one more film there, Party Girl (1958), which he had already signed for before this film appeared. Writer and producer Budd Schulberg never ceased to blame Ray, even years after his death in 1979, for the film's failure. Ray had made many alterations to Schulberg's script whilst on location; the film was extensively re-edited by Schulberg against Ray's wishes, causing some awkwardness in the film's construction. Ray also had difficult working relationships with leading men Burl Ives (who, at one point, offered to take over the direction of the film from him) and Christopher Plummer. However, many critics, especially in France, regard the film as one of Ray's best, despite all its shortcomings.
The film is based on a true account of a Florida game warden who was murdered by a family of bird poachers (called "plume rustlers") in the Florida Everglades.
Director Nicholas Ray was fired before the end of shooting by writer/producer Budd Schulberg. Schulberg finished directing the movie and supervised the editing, discarding a lot of Ray's original footage.
Cottonmouth snakes are indeed more deadly than their rattler cousins. They are also called water moccasins.