A Louisiana crawfish, or Procambarus clarkii, walks across a path in the Tiergarten park on August 24, 2017 in Berlin, Germany. Popular features in local aquariums, the crustaceans – also known as crayfish, freshwater lobsters, crawdaddies, mountain lobsters, yabbies and mudbugs – are not native to Germany. Conservationists believe they arrived in the park as a result of people emptying their aquariums there, possibly also the reason they appeared Frankfurt three years earlier. Although they are also considered pests, they are illegal to harvest for human culinary consumption as is habitual in what is considered their more natural habitat of the American South.
Adam Berry / Getty