Moose hunting

Two hunters went moose hunting every winter without success. Finally, they came up with a fool-proof plan. They got a very authentic cow moose costume and learned the mating call of a cow moose. The plan was to hide in the costume, lure the bull, then come out of the costume and shoot the bull. They set themselves up on the edge of a clearing, donned their costume, and began to give the moose love call. Before long, their call was answered as a bull came crashing out of the forest and into the clearing. When the bull was close enough, the guy in front said, "Okay, lets get out and get him." After a moment that seemed like an eternity, the guy in the back shouted, "The zipper is stuck! What are we going to do!?" The guy in the front says, "Well, I don't know how about you but I'm going to start nibbling grass."