Significant Diseases of Two Very Aged Red Foxes (Vulpes vulpes, Demarest 1820)

Wild mammal survival rarely approaches ages that are possible in genomic terms. Thus, sheltered environments present unique opportunities to study wild mammal aging and compare aging-related disorders to those of similar domestic animals. We evaluated two aged red fox vixens that had lived in a park setting where they were not caged, and were provided an environment that reflected a natural setting as closely as possible, while providing for proper nutrition and health care. During their 14th year, both foxes developed symptoms suggesting orthopedic and renal deterioration. After diagnosis, monitoring, and humane euthanasia, postmortem evaluation revealed degenerative joint and renal disease, each closely resembling organ-specific pathology of aged domestic dogs. Based on evaluation of these foxes and other recent reports, we hypothesize that underlying mechanisms for late life pathological changes reflect broadly and deeply conserved response capacities and not artificial environments, provided that shelter, nutrition, and health care are adequate to minimize stochastic mortality that prevails in the wild.