The idea of “wildlife reserves” for humans in the San Francisco Bay Area might seem ludicrous. But as metaphor and thought experiment, it is clarifying. The core idea is simply to designate limited areas in which housing would be fully legalized, removing almost all restrictions on its construction. By so doing, we would allow our own species to engage in behaviors necessary for the health of the local population, much like we give beavers full leeway to build dams and lodges within wildlife refuges.