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The Reproductive and Anatomical Characteristics of the Invasive Nutria (Myocastor coypus M.) in a Central European Population
1
Department of Wildlife Biology and Management, Institute for Wildlife Management and Nature Conservation, Hungarian University of Agriculture and Life Sciences, Páter Károly u. 1., H-2100 Godollo, Hungary
2
National Laboratory for Health Security, Hungarian University of Agriculture and Life Sciences, Páter Károly u. 1., H-2100 Gödöllő, Hungary
*
Authors to whom correspondence should be addressed.
Animals 2025, 15(24), 3524; https://doi.org/10.3390/ani15243524
Submission received: 3 November 2025
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Revised: 1 December 2025
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Accepted: 5 December 2025
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Published: 7 December 2025
(This article belongs to the Special Issue Adaptations for Animal Survival: Morphological Features or Physiological Mechanisms—Second Edition)
Simple Summary
The nutria is a non-native invasive species in Europe that causes significant damage to native ecosystems throughout the continent. The reproductive performance of this species in newly established territories in Central Europe is poorly understood. This research investigates the reproductive performance of this animal in a population in Slovakia. A total of 69 carcasses were collected during hunting season from Dlhá nad Váhom (Vághosszúfalu) and Dolné Saliby (Alsószeli). The postmortem investigation of carcasses revealed that the species was reproductively active in both spring and summer, with an average of seven embryos per female. These findings highlight the need for an intensive control programme to contain the rapid spread of the species and minimise its damage to local ecosystems.
Abstract
The nutria or coypu (Myocastor coypus M.) is endemic to South America. However, this species invaded Central Europe in the 19th century. The rapid spread of the invasive nutria across Central Europe triggered countless ecological conflicts with the local species. In the current research, we surveyed two populations in Slovakia and compared the reproductive performance of this species to its reproductive performance in other countries, where it is native. A total of 69 nutria were harvested from the wild in 2022–2024. The result of the postmortem analysis reveals no intersexual differences in the body weight and length. A visual inspection of the uterus among 25 female specimens confirmed that 16 (64%) were pregnant, including 3 individuals with the body size characteristics of young nutrias. The pregnancy rate was estimated at 90% (9 out of 10) in spring and 47% (7 out of 15) in autumn. The average number of embryos per individual was 6.94 ± 2.22 for all females, and it was 6.27 ± 2.05 in spring and 8.8 ± 1.64 in autumn, with no significant difference between seasons (p > 0.05). No clear relationship between the Body Mass Index (BMI) and the fertility of females, i.e., the number of embryos, was observed. Our results highlight the crucial need to raise public awareness about the invasive characteristics of the species and contribute to the establishment of an effective intervention techniques, including the establishment of the necessary legal framework for eradicating emerging populations across Central European habitats.
Keywords:
coypu; invasive alien species; Myocastor coypus; non-native; rodent; semi-aquatic; Slovakia
