We don’t know how North American crayfish hopped the pond, but scientists have announced that crayfish are proliferating in the Netherlands, Denmark, and Spain — and destroying salamanders and other amphibians in the process. Humans in Europe haven’t yet developed a taste for crayfish, so there is no natural predator of the invaders. Story here. This is ironic since in America we can’t get enough of crayfish, or crawfish, as we celebrate Mardi Gras.