It's for killing toucans. You hide in long grass and hold it up, and when a toucan approaches thinking it's seen a female in heat, you chop its head off. And make Guinness out of it.
I'm pretty sure that's for hunting deer, not toucans...after you've shot Bambi's mother and gutted the carcass, that knife is to help you section it into easily-transportable pieces. Ah, the great outdoors...
