There is no exact tally of how many species, like the pupfish, are now conservation-reliant. At a minimum, they number in the thousands. As for the forms of assistance they rely on, these, too, are legion. They include, in addition to supplemental feeding and captive breeding: double-clutching, headstarting, enclosures, exclosures, managed burns, chelation, guided migration, hand-pollination, artificial insemination, predator-avoidance training, and conditioned taste aversion. Every year, this list grows. “Old deeds for old people, and new deeds for new,” observed Thoreau.