The male antechinus engages in one of nature's most extreme reproductive strategies: suicidal reproduction, or semelparity. Every Australian winter, as the breeding season commences, male antechinuses enter an intense mating frenzy that lasts up to two weeks. During this period, copulation sessions can endure for up to 14 hours at a time.
To sustain this hyperactive pursuit without rest, the male's body suppresses its normal stress regulation mechanisms. Corticosteroid levels in the blood skyrocket, staying permanently elevated because the animal stops producing a crucial binding protein that usually neutralizes excess cortisol. This constant influx of stress hormones grants short-term stamina, allowing the male to constantly seek and mate with multiple females to maximize his chances of passing on genetic material.
However, the physiological toll is catastrophic. High corticosteroid levels trigger severe immunosuppression, causing immune system collapse, internal bleeding, gangrenous tissue loss, organ failure, and hair loss. By the end of the fortnight, every single adult male in the population dies from stress-induced physiological exhaustion, leaving behind a new generation raised entirely by the surviving females.