Originally Posted by KlondikeGeoff
I believe for rats and mice, it causes severe internal bleeding that offs them.
My understanding is since mice and rats routinely crawl into little spaces they bump themselves. Normally this bruising will bleed a tiny bit but with the newer rat poisons they bleed to death internally.
But in the Crime Library, there was an awful lot of "black widows" that seem to have gotten rid of their husbands with rat poison and I was like "There must've been something different in it way back then. Because the effect seemed to be more immediate.