Owl pellets and floating gold
Owl pellets used to fascinate me, the ejected contents of the digestive process of owls and other birds of prey, because they were full of bones, fur and feathers; an interesting find on a ramble. I would occasionally mistake a dog turd for an owl pellet and get a little too close before I realised. Sperm whales also sick up pellets of undigestible matter including the beaks of squid. Named "Ambergris" it is called by some "floating gold" because the perfume and flavourings industries buy it at up to 20 dollars per gram. "It's quite remarkable when you think about it, because when the whale throws this out, it's discarded material that they can't digest," Mr Jury explained...[But] after 10 years, it's considered clean and all you're getting then is the wonderful musky, very sweet perfume, which I've got to say is ultra smooth - it's unbelievable." (from the BBC website, article title: Ambergris, Intestinal excretion of sperm whale)