Enter these cheats at the Map: 

Cheat code:             Effect:
bgshow                  show animals
bgtrack                 move faster
bgurine                 attract animals
bgvampire               show blood trails

Enter these cheats at the Main Menu:

Cheat code:             Effect:
bgnoah                  more animals
bgsteroids              trophy animals
bghorns                 sheep only
bgelabong               elk only
bgbullwinkle            moose only
bgyogi                  bear only

Enter these cheats during gameplay: 

Cheat code:             Effect:
bgbarbecue              rocket launcher
bgweather               change weather
bgpredator              infrared vision
bgsniper                no gun movement