Variation in Hematologic Reference Values in captive and free-ranging South American Gray Fox (Lycalopex griseus)

Establishing species-specific hematological reference values for wildlife species is essential for comprehensive health assessments and early disease detection. This study aimed to determine hematologic reference values for the South American gray fox ( Lycalopex griseus ) and assess differences between free-ranging and captive individuals. We examined 32 L. griseus , including 14 captive foxes from Santiago Zoo Metropolitan Park and 18 free-ranging individuals from sheep ranches and natural environments in Chilean Patagonia. Only clinically healthy animals were included. Statistical analysis revealed significant differences in hematologic parameters between populations, with reference values presented separately for each group. Differences were primarily observed in specific white blood cell lineages, as eosinophil, lymphocyte, and monocyte counts were substantially higher in free-ranging foxes. This suggests a more active immune status in wildlife individuals, underscoring the need for environment-specific reference intervals. Further research is warranted to investigate health status and factors influencing hematologic parameters in L. griseus , thereby supporting conservation efforts.