The Habitats Directive and Endangered Species Act (ESA) are the primary legal instruments governing species protection in the European Union and United States, respectively. These two legal regimes locate the responsibility for their implementation, administration, and enforcement at different levels of government, or governance. The division of responsibility between the Federal authority, state governments, and non-government actors is perhaps the most significant distinction between these two systems. This article looks at this division of responsibility along with several legal features of the two instruments: the prohibitions on killing protected species, the role of hunting, their enforcement mechanisms, and their flexibility to adapt to changing or uncertain circumstances in nature. These features highlight some differences in the legal mechanisms of the Habitats Directive and ESA, as well as some surprising similarities. As the EU continues to gain federation-like competences, it is not surprising that responsibility for biodiversity protection has shifted from the states to the central authority. This authority is also shifting from the state to the non-state actor. In this way, biodiversity protection in the United States and European Union is becoming more similar.