Ottomar Anschuetz was doing literally wild B&W images in the 1880`s. A couple of years later, the Keaton Brothers in England redefined wildlife photography. They invented the portable blind in 1897. Arthur Radclyffe was a man with great mechanical skills, who invented a 5x7 "reflex" view camera and photographed wildlife in Africa. He usually carried a very large gun under his arm as he had to get quite close to his sibjects, which included rhinos and cape buffalo.
One of the most famous B&W wildlife photographers was Eric Hosking, whose bird images are pure visual poetry. The American Leonard Lee Rue III focused more on mammals of North America. His images were classic textbook illustrations for several decades. Europe took B&W wildlife photography a step further, forming associations of photographers in Spain, France, Germany and Scandinavia in the 1930`s. But while these photographers are still great soures of inspiration, today`s magazines reflect little if anything of this challenging subject.
It is probably one of the toughest subjects in B&W. I`d be interested in seeing any recent work apart form Nick Brandt and James Balog.