Some populations of city mice are ridiculously hardy. They can eat warfarin-laced poison food like it's candy. It's like the roaches in some Washington D.C. bu

Some populations of city mice are ridiculously hardy. They can eat warfarin-laced poison food like it's candy. It's like the roaches in some Washington D.C. buildings that are immune to virtually every chemical used for pest control. It's so bad that chemical companies test new compounds on those populations first. That's what decades of selective breeding has brought about.