In vivo semen characterization and seasonal variation in Procavia capensis

Male fertility traits are poorly characterized in most wild mammals. The rock hyrax (also known as rock rabbit) is a seasonal breeder with a short mating period each year, but little was known about its male reproductive physiology because semen studies relied on post-mortem material. We established a non-lethal protocol for semen collection in rock hyraxes and applied it both in captivity and under natural desert conditions. This enabled detailed analyses of sperm's shape (morphology), architecture (ultrastructure), and dimensions (morphometry), and seasonal semen changes. We found that sperm concentration, motility, and normal morphology were highest during peak breeding season but declined sharply only a few weeks later, accompanied by structural abnormalities and signs of disrupted spermatogenesis. Our study reveals sharp seasonal shifts in male fertility and demonstrates a safe, repeatable method for studying reproduction in wild mammals, with potential applications in conservation and comparative studies among seasonal species.