A surprising number of alien, or non-native, amphibian and reptile species are present in the wild in the UK today. Species present range from unwanted pet terrapins, surviving as non-breeding animals, to long-established, breeding populations such as midwife toads and wall lizards. Whilst in most cases, introduced species do not thrive as they are not adapted to their new environments, of a minority that can survive in their new home some can impact upon native species. Amphibian and Reptile Conservation has produced an illustrated guide to the alien amphibian and reptile species in the UK.