In January 2001, 52 elk stepped off trucks into the Cataloochee Valley and started rebuilding an ecosystem that had been quietly failing for 226 years. Scientists expected to wait fifteen years for a response. They waited one growing season.

There are two ways to sterilize a cocaine hippo. Both require finding the hippo first. Loki reviews the field surgery, the immunocontraceptives, the Apple Watch on the tongue, and the arithmetic of an ecological problem that grows at six percent per year regardless of your feelings about it.