Patterns of Testosterone in Male White-tailed Deer (Odocoileus virginianus): Seasonal and Lifetime Variation

Testosterone is strongly associated with the annual development of antlers in cervids, but. endocrine research on wild, freely breeding ungulates is often done without repeated capture of known-aged individuals. As a result, our knowledge on how testosterone fluctuates over the course of a lifetime and variation in lifetime patterns among individuals is limited. We investigated patterns of testosterone in a freely breeding population of white-tailed deer (Odocoileus virginianus) in Alabama, USA that breeds in January. Testosterone peaked during the height of the breeding season, despite this period occurring approximately two months later than in most temperate-region, white-tailed deer populations. Age-related differences in testosterone were only prevalent during the breeding season, with bucks ≥3.5 years old having greater testosterone (853 ng/dl ±96 SE; P = 0.012) than bucks 1.5–2.5 years old (364 ng/dl ±100 SE). Additionally, an individual’s testosterone level as a yearling was not...