The chambered nautilus, with its spiral shell and up to ninety tentacles, is a bizarre and beautiful cephalopod. It has remained largely unchanged through five hundred million years and five major extinction events, but now global demand for nautilus shells is driving it to the brink. Sarah Uhlemann of the Center for Biological Diversity explains to host Steve Curwood that her organization is petitioning the National Marine Fisheries Service to list the chambered nautilus under the Endangered Species Act.