Call of the Wild

Ranchers name their poison

A mortal enemy of the $70 billion American livestock business is the wild coyote. Ranchers claim that last year alone predators—mostly coyotes—marauding from Montana to Texas devoured stray livestock worth $200 million. They have tried fencing off their land, trapping the animals and even shooting them from low-flying airplanes. But ranchers argue these methods always proved unrealistic, inefficient or too expensive. The most effective means of controlling the predators was to scatter animal carcasses laced with a strong poison across pastureland.

For decades, the most widely used poison was a...