Non-native common snapping turtle Chelydra serpentina (Linnaeus, 1758) in Western Europe: a focus on Central Italy showing evidence of a hot spot of introduction


  • Vincenzo Ferri Societas Herpetologica Italica, Sezione Lazio. Via Valverde 4, 01016 Tarquinia, Italy
  • Corrado Battisti “Torre Flavia” LTER (Long Term Ecological Research) Station, Protected Areas – Regional Park Service, Città Metropolitana di Roma Capitale, viale G. Ribotta, 41, 00144 Rome, Italy
  • Giulia Cesarini National Research Council – Water Research Institute (CNR-IRSA), Corso Tonolli 50, 28922 Verbania, Italy AND Department of Sciences, University of Roma Tre, viale G. Marconi 446, 00146 Rome, Italy
  • Massimiliano Scalici Department of Sciences, University of Roma Tre, viale G. Marconi 446, 00146 Rome, Italy AND National Biodiversity Future Center (NBFC), Università di Palermo, Piazza Marina 61, 90133 Palermo, Italy



alien species, biological invasion, colonisation hub, illegal trade


The common snapping turtle, Chelydra serpentina (Linnaeus, 1758), is a robust aquatic turtle native to southeast North America. However, it has also been introduced to other countries through the exotic pet trade, where it has gained popularity due to its distinctive appearance and impressive size. Over the past decade, a considerable number of individuals, abandoned by their owners, have been recorded and captured in Western Europe. Here, we report the first comprehensive summary of records at continental scale, showing that France and Italy represent the countries with the highest number of sightings. In France, exhibition, exchange, or sale events of exotic animals (until 2022 legal; now illegal) have been located near large cities, although records of C. serpentina were significantly higher outside the core of urban areas. We also recorded a significant increase in total number of records at European scale when comparing the periods of 2010-2015 and 2016-2020. Finally, we focused the current study on a peculiar spatial pattern at local scale (Central Italy) near an important site of exhibition and sale events of exotic animals, suggesting the presence of a hot spot of introduction. Popular events may represent critical colonization hubs from where these freshwater turtles can disperse into the surroundings.


1. Ernst C.H., Barbour R.W. & Lovich J.E. (1994). Turtles of the United States and Canada. Smithsonian Institution Press, Washington and London.

2. Ferri V. & Soccini C. (2015). Guida alle Tartarughe e Testuggini del Mondo. Franco Muzzio Editore, Padua, Italy, 432 pp.

3. Alexander M.M. (1943). Food habits of the snapping turtle in Connecticut. Journal of Wildlife Management 7: 278–282.

4. Aresco M., Margaret J. & Gunzburger S. (2007). Ecology and morphology of Chelydra serpentina in Northwestern Florida. Southeastern Naturalist 6 (3): 435–48.

5. Bosch A. (2003). Chelydra serpentina Animal Diversity Web. Available from [accessed 25 August 2023].

6. Steyermark A.C., Finkler M.S., Brooks R.J. & Gibbons W. (2008). Biology of the Snapping Turtle (Chelydra serpentina). The Johns Hopkins University Press, Baltimore, 240 pp.

7. Keevil M.G., Noble N., Boyle S.P., Lesbarrères D., Brooks R.J. & Litzgus J.D. (2023). Lost reproductive value reveals a high burden of juvenile road mortality in a long-lived species. Ecological Applications 33 (3): e2789.

8. Piczak M.L., Markle C.E. & Chow-Fraser P. (2019). Decades of road mortality cause severe decline in a common snapping turtle (Chelydra serpentina) population from an urbanized wetland. Chelonian Conservation and Biology 18 (2): 231–240.

9. Kobayashi R., Hasegawa M. & Miyashita T. (2006). Home range and habitat use of the exotic turtle Chelydra serpentina in the Inbanuma Basin, Chiba Prefecture, Central Japan. Current Herpetology 25 (2): 47–55.[47:HRAHUO]2.0.CO;2

10. Kobayashi R. (2007). The risk of establishment of snapping turtles and alligator snapping turtles in Japan: development of a method for monitoring exotic pet release using news articles. Bulletin of the Herpetological Society of Japan 2: 101–110.

11. Kikillus K.H., Hare K.H. & Hartley S. (2010). Minimizing false negatives when predicting the potential distribution of an invasive species: a bioclimatic envelope for the red-eared slider at global and regional scales. Animal Conservation 13 (suppl. 1): 5–15.

12. Kopecký O., Kalous L. & Patoka J. (2013). Establishment risk from pet-trade freshwater turtles in the European Union. Knowledge and Management of Aquatic Ecosystems 410 (2): 1–11.

13. GBIF (2023). Global Biodiversity Information Facility. GBIF Secretariat Universitetsparken Copenhagen, Denmark. Availabe from [accessed 20 June 2024].

14. Ferri V., De Luca L., Soccini C. & Pandolfi M. (2016). La tartaruga azzannatrice, Chelydra serpentina (Linnaeus, 1758), nel fiume Tevere (Lazio). Biologia Ambientale 30: 45–48.

15. Meylan P.A. (2006). Biology and Conservation of Florida Turtles. Chelonian Research Monograph No. 3, Chelonian Research Foundation, Luneburg, Maine.

16. Munscher E C., Butterfield B.P., Carstairs S., Dupuis-Désormeaux M., Munscher J., Osborne W. & Hauge B. (2015). The turtle head immobilization system (THIS): a tool for faster and safer handling and processing of aggressive turtle species. IRCF Reptiles & Amphibians 22 (4): 173–177.

17. Di Santo M.P., Vignoli L., Carpaneto G.M. & Battisti C. (2017). Occurrence patterns of alien freshwater turtle in a large urban pond ‘Archipelago’ (Rome, Italy): Suggesting hypothesis on root causes. Lakes and Reservoirs: Research and Management 22: 56–64.

18. Esposito G., Di Tizio L., Prearo M., Dondo A., Ercolini C., Nieddu G., Ferrari A. & Pastorino P. (2022). Non-native turtles (Chelydridae) in freshwater ecosystems in Italy: A threat to biodiversity and human health? Animals 12: 2057.

19. Edgreen R.A., Edgren M.K. & Tiffany L.H. (1953). Some North American turtles and their epizoophytic algae. Ecology 34 (4): 733–740.

20. Ziglar C.L. & Anderson R.V. (2005). Epizoic organisms on turtles in Pool 20 of the upper Mississippi River. Journal of Freshwater Ecology 20 (2): 389–396.

21. Bologna M.A., Bagnoli C. & Carpaneto G. (2000). Anfibi e Rettili del Lazio. Palombi Editore, Roma, 118 pp.

22. Monaco A. (ed.) (2014). Alieni. La minaccia delle specie alloctone per la biodiversità del Lazio. Palombi Editori, Roma, 256 pp.

23. McKnight C.M. & Gutzke W.H. (1993). Effects of the embryonic environment and of hatchling housing conditions on growth of young snapping turtles (Chelydra serpentina). Copeia 2: 475–482.

24. Ministero dell’Ambiente (1996). Decreto del Ministero dell’Ambiente del 19 aprile 1996. Elenco delle specie animali che possono costituire pericolo per la salute e l’incolumità pubblica e di cui è proibita la detenzione. Gazzetta Ufficiale 3 ottobre 1996, n. 232. Available from [accessed 20 June 2024].

25. Repubblica Italiana (2017). Decreto legislativo 15 dicembre 2017, n. 230. Adeguamento della normativa nazionale alle disposizioni del regolamento (UE) n. 1143/2014 del Parlamento europeo e del Consiglio del 22 ottobre 2014. (18G00012). Gazzetta Ufficiale U, Serie Generale, 24, 30-01-2018. Available from [accessed 20 June 2024].

26. Marini D., Ferri V., Soccini C. & De Luca L. (2019). Occurrence of corn snake, Pantherophis guttatus (Linnaeus). European Herpetological Society, 20th European Congress of Herpetology, Milan (pp. 2–6).

27. Nerozzi I., Soto I., Vimercati G., Capinha C., Tarkan A.S., Kraus F., Haubrock P.J., Pauwels O.S.G., Zuffi M.A.L. & Balzani P. (2024). Potential distribution, observed impacts, and invasion risk of two non-native snapping turtles, Chelydra serpentina and Macrochelys temminckii. Biological Invasions 1–18.

28. de Volder S., McLennan S. & Schmit V. (2013). Eurogroup for Animals. Analysis of National Legislation Related to the Keeping and Sale of Exotic Pets in Europe. Eurogroup for Wildlife & Laboratory Animals, European Commission Available from [accessed 20 June 2024].

29. Thévenot J. & de Massary J.-C. (2019). Chélydre serpentine (La), tortue serpentine (Français). Chelydra serpentina (Linnaeus, 1758). Fiche dscriptive. Available from [accessed 20 June 2024].




How to Cite

Ferri, V., Battisti, C., Cesarini, G., & Scalici, M. (2024). Non-native common snapping turtle Chelydra serpentina (Linnaeus, 1758) in Western Europe: a focus on Central Italy showing evidence of a hot spot of introduction. Belgian Journal of Zoology, 154, 73–82.