The evolutionary and ecological convergence of the raccoon and raccoon dog: A perfect storm of invasive species in Europe

Abstract

This paper initially describes the evolution of body shape in the raccoon ( Procyon lotor ) and the raccoon dog ( Nyctereutes procyonoides ). I explain how their similarities are the result of convergent evolution, the process by which unrelated organisms come to resemble one another in form, function, or both. This is the first examination of this phenomenon in these two species. In addition, I consider how their convergent traits and habits as omnivores have contributed to their astounding success as invasive species in Europe. Problems have arisen from these introductions, including impacts on prey species. Considering their broad adaptability as “stout” shaped mesocarnivores should aid in understanding their behavior and ecology, and could assist in addressing their management in Europe. Last, I offer suggestions for the control of raccoons given their compensatory versus additive mortality patterns, a practice that may also have implications for the regulation of raccoon dog populations. 本文首先描述了浣熊（ Procyon lotor ）和貉（ Nyctereutes procyonoides ）体型的进化过程。我解释了趋同进化如何导致它们的相似性，即无关的生物如何通过趋同进化在形态、功能或同时在两个方面都变得彼此相似。这是首次对这两个物种的这一现象进行的研究。此外，我还探讨了它们作为杂食动物的趋同特征和习性是如何促进它们作为入侵物种在欧洲取得惊人成功的。这些物种的引入产生了一些问题，包括对猎物物种的影响。考虑到它们作为“矮壮型”中级食肉动物的广泛适应性，有助于理解它们的行为和生态特性，也有助于解决它们在欧洲的管理问题。最后，我提出了一些基于浣熊的补偿性与叠加性死亡模式的种群管控的建议，这一做法可能也会对貉的种群管控具有启示意义。 A novel explanation for the evolution of body shape in the raccoon and the raccoon dog is provided, with discussion of the basis for their convergent evolution. Due to releases in Europe in the 20th century, both of these omnivorous mesocarnivores have become highly successful, and have had negative impacts on its native fauna including populations of amphibians, turtles, and birds. Suggestions for their management are offered, consistent with their classification by the European Union as invasive alien species. Control of raccoons should consider their compensatory versus additive mortality patterns, which show that harvests of over 40% of their autumn population sizes are necessary for their control.