By all rights, male Nidoran should be more common than their female counterparts in the wild. They have a sharper hide, a more potent venom, and a long horn, all of which make them much more able to defend themselves. But a male Nidoran's horn is a double-edged one, as it is for this horn's special properties that they have been hunted to rarity, if thankfully not a place next to Bulbasaur, Lapras, and Farfetch'd on the Endangered Pokemon List.

When ground up, the horn produces a nearly tasteless poison which can knock a grown man out instantly. This poison is typically used by kidnappers and date rapists, and a lucrative black market exists in the Nidoran horn trade. Although some are harvested by scientists for legitimate uses, such as Rapidash tranquilizers, the vast majority are traded in the black market.

Some have advocated a program of tagging Nidoran to effectively snuff out this trade, but their pleas have been rejected on the grounds of expense. Instead, the police content themselves with occasional raids and monitoring of habitat which have proven ineffective at stopping the poaching of Nidoran horns.