As we entered the bush on the first day of the hunt, Deo told me that, unlike most chimps, Saddam was a loner. It was very likely that the rest of his group was decimated by deforestation and poaching. Saddam, though, had adapted to life in what remained of the forest around the village of Ruteete. He had learned to avoid humans when possible but became a skilled raider of their crops. When there were no suitable trees, he made nests on the ground.

Saddam’s home range was vast, and the forest was dense (where it hadn’t been cleared). After each sighting by a villager, his trail quickly went cold. So instead of following him, we decided to stake out places Saddam was likely to turn up — usually, one of the village’s makeshift banana-beer breweries. Saddam was drawn to the smoky, overripe bananas. He had even been seen drinking handfuls of the beer from the hollowed-out trees where it fermented.

We kept watch all day, every day, for more than a month, sweating in the shade of banana trees and passing time by chewing sugarcane and whittling sticks into toothpicks. Finally, on one Thursday afternoon in late July, Deo touched my shoulder and pointed to the trees in the back of the banana grove. They had started to shake. A chimp’s black shape came in and out of view as he slowly moved toward us. At last he emerged — Saddam, without a doubt — knuckle-walking toward a huge stack of fermenting bananas. When I practiced with the gun, I was able to hit targets smaller than his torso from the same distance. But then he started to charge.

Through the sight of the rifle, I watched Saddam come at me. All I had to do was squeeze the trigger. But I stood frozen as he advanced to within a few feet. I braced myself, but suddenly Saddam pivoted right and stormed noisily into the forest. That was the last time I saw him.