Extreme sexual aggression is driving female tortoises to leap from cliffs to escape males.
On the island of Golem Grad in North Macedonia, a harrowing survival crisis is unfolding among Hermann’s tortoises. According to a study published in the journal Ecology Letters, male tortoises now vastly outnumber females, with ratios reaching as high as 19 to one in some areas. This imbalance has triggered a wave of relentless sexual aggression, where multiple males bite, bump, and mount a single female simultaneously. In a tragic bid for relief from this constant harassment, researchers have observed female tortoises walking off high cliffs, often resulting in fatal falls or debilitating injuries.
This phenomenon, which experts have termed "demographic suicide," is causing female survival and reproduction rates to plummet. Lead author Dr. Dragan Arsovski and his team analyzed 16 years of data, revealing that harassed females are frequently overwhelmed and physically traumatized by aggressive suitors. The environmental impact of this behavior is catastrophic; ecologists now predict that if the current trend persists, the last female tortoise on the island will perish by 2083. This localized extinction serves as a grim example of how extreme social imbalances can drive a once-prosperous population toward total collapse.
source: Arsovski, D., et al. (2026). Sex Ratio Bias Triggers Demographic Suicide in a Dense Tortoise Population. Ecology Letters.