Chemical horn infusions--a poaching deterrent or an unnecessary deception?

Poaching for horn remains a significant threat to rhinos. Conservationists use various approaches to deal with the threat. One method advocated is infusing rhino horns with chemicals and dye. Promoters of this method claim the procedure renders the horn useless and that ingesting poisoned horn carries potential risk to the end-user. We visually examined white rhino horn that had been treated; we examined available literature; and we obtained expert opinion to assess several assumptions and risks associated with the approach. We found the information on which the assumptions are based to be weak, and refute claims that discolouring horns is a viable method. Our assessment contests the efficacy of this technique on conceptual and logistical grounds, especially when dealing with relatively large populations. We argue that conservationists should not use this technique to deal with the rhino poaching threat.