I've read about those! It's amazing how enzymes and bacteria can change their digestion to utilize stuff that would have killed them some generations ago! If and when the human race will remove itself from the food chain, nature seems to have the ability to heal itself in no time. Just think about what kind of a paradise some space travelling aliens would find after we've left... With some luck they'd be some ammonia breathing turtles accustomed to a sub-zero climate, wanting to make it like home.
Actually crude oil is 100% natural
They found this oil eating bacteria in some cave IIRC.
