You’d think having trillions of cells would make elephants more prone to cancer—but it’s just the opposite. Thanks to a genetic superpower, these giants are unusually cancer-resistant.

While humans have just one copy of the tumor-fighting p53 gene, elephants have around 20. This gene acts like a molecular bodyguard, detecting damaged cells and either fixing them or ordering them to self-destruct before they become dangerous. More copies mean more vigilant guards—and far fewer tumors.

It’s a powerful solution to a scientific mystery known as Peto’s Paradox: Why don’t bigger animals, with more cells, get more cancer? In the case of elephants, evolution answered with extra genetic firepower.