There’s something strange about the elephants in Mozambique’s Gorongosa National Park. Fewer elephants have tusks. And more elephants are females.

Researchers think they know why. The herd is evolving. So many elephants were killed for their tusks that the species itself is changing.

Casualties of war

Elephant tusks are made of ivory. These big teeth can weigh more than 100 kilograms. There’s a huge demand for ivory on the black market. One tusk can sell for half a million dollars!