Introduction The raccoon dog Nyctereutes procyonoides (Gray, 1834) is a newly established alien species that has had a long and complicated history of introduction and immigration within Europe. The historical distribution of this species was in the Far East, from northern Indochina to the southeast corner of Russia, and also in Mongolia and in the Japanese Archipelago. The native range covers East Asia, the Amur-Ussuri region in Russia, northern Vietnam, Korea, China, and Japan (Lavrov, 1971; Kauhala and Saeki, 2004). Currently six subspecies of N. procyonoides are recognized: N. p. ussuriensis inhabits Russia, northeastern China, and Eurasia; N. p. procyonoides inhabits Vietnam and southern China; N. p. albus and N. p. viverrinus inhabit Japan; N. p. orestes inhabits China; and N. p. koreensis inhabits the Korean Peninsula (Hong et al., 2013). The introduction of raccoon dogs as fur-bearing animals into Siberia and the European part of the former Soviet Union started in 1929 and continued until 1955 (Kauhala and Saeki, 2004; Ansorge et al., 2009). One part of these animals was introduced to Europe from breeding farms and another part from reacclimatized sites after World War II. The majority of captive bred raccoon dogs of the subspecies N. p. ussuriensis (about 9000-10,000 animals) were released in several places during the 1940s and 1950s (Lavrov, 1971; Kauhala and Saeki, 2004; Ansorge et al., 2009) (Figure 1a). After active introductions and acclimatization in the European part of Russia, the raccoon dog has dispersed into new areas without active human support and has spread rapidly into many European countries (