In the 1980s, in South Africa's Transvaal province, several ranches were affected by abnormal mortality of greater kudu (Tragelaphus strepsiceros), antelopes bred for hunting. No blood, no bite marks. A real mystery. Scientists discovered that the stomachs of these animals were filled with undigested acacia leaves, due to their high concentration of tannins. Free-ranging kudu, on the other hand, are not affected, as they can change trees when the tannin concentration rises. Curiously, they always move into the wind. In fact, browsed acacias emit a volatile compound, ethylene, which diffuses into the air over a distance of a few meters and induces the synthesis of chemical compounds. This defense strategy enables acacias to adapt to their environment and preserve their survival.