Do any animals use objects as weapons?

Kat - This is a very interesting one, I've been looking into it a bit and there is some research. It was published in 2007 in the journal Current Biology which does describe chimps using spears. These are sticks that they had broken off and sharpened with their teeth. What they were doing was stabbing them, these sticks, into holes in tree trunks where these little bush babies sleep that the chimps can eat. The researchers saw them doing this stabbing thing and they wondered if they were trying to chase out the bush babies. But they actually saw a chimp stab a bush baby, pull it out on the stick and eat it, suggesting that this is actually hunting behaviour and these chimps are in fact using their sticks as weapons!