Recent advances in synthetic biology have made it possible to revive extinct species of animals, a process known as ‘de-extinction’. This paper examines two reasons for supporting de-extinction: the potential for de-extinct species to play useful roles in ecosystems; and human valuing of certain de-extinct species. I focus on the particular case of passenger pigeons to argue that the most critical challenge for de-extinction is that it entails significant suffering for sentient individual animals. I also provide reasons to take existence (...) value, or valuing the mere the fact that a species exists, into consideration in debates over de-extinction. (shrink)