The story that beavers self-castrate when cornered by hunters appears in a range of Roman sources, both poetry and prose, from the end of the Republic onward. This myth is a product of the rôle that ‘beaver testicles’ played in Roman luxury trade and medicine. At the same time, it serves as a literary figure for the fraught relations between Rome and the provinces from which these, and other, luxury goods were imported.

Species reintroduction programmes are an important feature of global conservation efforts. There is evidence within the texts of some international and European laws of legal obligations to reintroduce species to their former habitats. However, these obligations are inconsistent between legal instruments, and it is not at all clear exactly what it is they are legislating to recreate. In particular, definitions of native species are either absent from the law or unclear, especially in an historical context. Attempts to reintroduce some predators have been met with legal challenges, and so it is essential that conservation authorities have a clear mission in their reintroduction activities and that this mission is reflected in their national law. Successful reintroductions will be achieved only with public support, and this is more likely where clear objectives have been established after public consultation. Conservation authorities undertaking reintroduction projects should use the legal system and the international commitments made by their governments to validate their efforts.