Suspected Hip Dysplasia in a Red Fox

We report skeletal features that are consistent with hip dysplasia, as it is described in domestic dogs (Canis lupus familiaris) in a museum specimen of a red fox (Vulpes vulpes). Morphological identifiers included shallow acetabulae, femoral head flattening and subluxation, caudal curvilinear osteophyte, circumferential femoral head osteophyte, osteophytes of the acetabular margin, and femoral neck remodeling. Hip dysplasia has low-tomoderate quantitative heritability in dogs, while the contributing environmental and epigenetic influences are understood only marginally. Genomic, epigenetic, and environmental influences on hip joints of wild canids are not known. Potential population consequences of hip dysplasia, or hip dysplasia-like conditions, in free-living populations of wild animals, remain speculative. Possible concerns for affected individuals include reduced predatory and breeding efficiency, greater tendency to focus on local prey that are caught most easily, and greater risk as targets for predation. Progressive dissemination of hip joint diseases in a population could raise concerns about sustainability, altered size and density of prey populations, and local invasion by other predators. Our observations suggest a need for new research to better understand the biological nature of the disease(s) that these features represent, as well as suggesting new pathways for the studies of musculoskeletal disorders among Canidae.