[Junior]

Monkeys have opposable thumbs, and I have yet to see one who was capable of using (let along creating) a 30.06 rifle to shoot bananas out of a tree.

Monkeys and apes have been known to use tools -- a rifle is simply a much more complex tool. Lower animals also use tools: sea otters use rocks as hammers and anvils to crack oyster shells, some birds fashion [1] twigs to dig out insects from trees, etc.

[1] The word "fashion" was used on purpose. Not only do they select the stick for the function, they also modify the stick to more closely suit their needs.

[Alberta's Child]

Excellent points. It's worth noting, though, that every action of these animals (as far as we can tell, and we'll assume this to be the case unless proven otherwise) is directly focused on eating or mating (in other words, survival). Humans are the only species that will do something simply for the hell of it.