Enter these cheats at the Map:

bgshow 		show animals        
bgtrack 	move faster         
bgurine 	attract animals      
bgvampire	show blood trails    

Enter these cheats at the Main Menu:

bgnoah  	more animals         
bgsteroids  	trophy animals       
bghorns  	sheep only           
bgelabong  	elk only            
bgbullwinkle  	moose only          
bgyogi  	bear only           

Enter these cheats during gameplay:

bgbarbecue 	rocket launcher       
bgweather 	change weather       
bgpredator 	infrared vision      
bgsniper 	no gun movement 

Thanks to Revolution reader Dennis Taylor!