Golem Grad's Tortoises Are Thriving. They're Also Going Extinct.
A small island in a mountain lake in North Macedonia. No dogs. No rats. No hunters. Warm climate, good grass, steep cliffs keeping the rest of the world out. By every rule of conservation biology, the tortoises here should be doing great.
They are. And they're destroying themselves. On Golem Grad, Hermann's tortoises pack in at 50 per hectare — the densest population ever recorded for the species. Around 1,000 animals total. The island is strictly protected. Adults have no predators.
They also have, depending on where you stand, up to 19 males for every single female.
The males chase. They ram. They bite. Up to three-quarters of the females carry injuries. They're exhausted, underweight, reproducing less. Some of them have started going over the cliffs that ring the island plateau.
Scientists are calling it "demographic suicide," the first known case of a wild animal population collapsing from the inside, driven entirely by a sex ratio gone badly wrong. Sixteen years of data back the projection: the last large female on Golem Grad dies around 2083. Nobody is certain how the imbalance started. A random fluctuation, maybe, or however the original tortoises arrived.
The island keeps its tortoises. The population does not survive them.
The strangest extinction stories are the ones where nothing went wrong from the outside.
Read the full story at Phys.org, May 10, 2026
Hot Take: A fully protected island, no predators, a mild climate, a thriving population, and the females are still being chased off cliffs. Conservation biology does not have a checklist item for this, and it should.
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