How to survive on a heart-stopping diet

Monarch butterflies, milkweed bugs and tiger keelback snakes may be very different creatures, but they have some things in common. These master chemists all contain heart-stopping toxic steroids, and have distinctive bright orange markings that warn predators: “if you eat me, you’ll regret it.” It’s difficult to believe, then, that any predator would make a meal of such obviously dangerous prey. But our research is discovering that predators from Germany to Australia and from Mexico to Japan have evolved remarkable abilities to withstand these toxins, and to survive on a most dangerous diet.