An invasive species of crayfish (also known as Marmorkrebs or Procambarus virginalis) is spreading rapidly throughout Europe, and threatening endemic wild species as a result, due to its ability to clone itself. Genetically identical crayfish are now thriving in the wild from subtropical Madagascar to Sweden, Japan and Germany. It has been found in cities too, including Hanover and Heidelberg. The new species was discovered in a German aquarium in 1995, and is likely to have occurred as a result of a single mutation in a slough crayfish. This mutation is also responsible for the crayfish’s ability to clone itself.