Protecting the world’s endangered wildlife is a major law enforcement challenge. Poachers, often paid by organized criminal networks, have vast wilderness areas in which to operate. Rangers and police are frequently overstretched and sometimes outgunned. Even when arrests occur, cases can be difficult to prove and successful prosecutions are rare. But new tools, ranging from drones to game theory, are starting to make progress. Now the techniques of forensic genetics used in human crime scene analysis are entering the fray.