Cats go wild while staying at home: First indication and behavioral assessment of potential European wildcat-hybrids living as companion animals

Populations of the European wildcat ( Felis silvestris ) are threatened across the continent. Their widespread hybridization with domestic cats ( Felis catus ) represents a major threat. It is worrisome that some hybrids can basically function in the same ecological niche as wildcats do. However, hybrid cats may represent a genetic and morphological spectrum, and it is unknown whether introgression of wildcat genes could result in hybrids living unnoticed as companion animals. We hypothesized that in Hungary, where the wildcat has a slowly spreading population, their likely hybridization with rural domestic cats, resulted in hybrids living under human care. We interviewed cat owners about the morphology and behavior of their cats in a large-scale citizen-science survey. We objectively scored the cats’ apparent hybrid characteristics from the submitted photographs. Cats with the highest hybrid-category represented 18% of the sample. Importantly, these cats were thought to be the least dependent on human caretaking (P=0.020) and greeted other cats least often with their ‘tail-up’ (P=0.018). Tabby-colored cats reportedly wandered farther from the house (P=0.009) and guarded their food more fiercely (P=0.003) than non-tabby cats. The wide spatial distribution of hybrid-looking cats indicates that the potential hybrids became an organic part of the Hungarian companion cat population. This is the first indication that wildcat hybrids may be spontaneously born in anthropogenic environment, and despite their markedly different behavior, they can successfully thrive as companions. These results may bear great importance when we consider the status and future of the threatened wildcats in densely inhabited areas. • Wildcat introgression to domestic cats is expected at the edges of the wildcat population expansion zones. • We show new approach in assessing phenotypically companion cats for signs of hybridization. • More than 10% of the surveyed cats showed convincing hybrid-features on their pelage. • Low human-dependence and infrequent tail-up greeting towards other cats is associated with hybrid-features. • Potential hybrids in the companion cat population can have relevance for conservation efforts.