Elephants Use Tools!

I guess everybody knows this already, but elephants use tools! Dr. Theresa was watching a PBS show about crows. I was lying there half-listening and reading my Sun Ra biography. Anyhow, this young biologist on the TV casually drops the fact that chimpanzees, crows, and elephants are the only animals (besides people, he forgot to say) who use tools. I have mentioned the fact that crows use tools on this "blog" before. But elephants? What kind of tools do they use? I'm too tired to look it up. Seems like something I should have been informed about before.