The most common forms of rat poison are anticoagulants (poisons that cause uncontrolled bleeding). When a rodent is poisoned, it usually goes outside to die. There, it become slow, easy prey for snakes, foxes, hawks, owls, raccoons, and even your neighbor’s cat.
We understand that live traps and snap traps don’t always work in cases of severe infestation. If you absolutely must use a poison, the only form of poison that appears harmless to predators is cholecalciferol, a synthetic form of vitamin D. Vitamin D rodenticides use megadoses of the vitamin to poison rodents. It’s highly effective but not not appear to harm predators.