It reproduces by cloning. The first one, discovered only 25 years ago, was a female. All subsequent ones have been female. They are almost genetically identical to one another. They clone pretty often, almost every day. One scientist says, “Three of us once caught 150 animals within one hour, just with our hands.” The crayfish made its way to Madagascar in 2007; now there are millions of them. They are moving across Europe. When will they come here?