Maybe an hour later a canoe came into view. It was long, twenty feet at least, and two natives clad in nothing more than loincloths were standing in it—one at the front, one at the back—both guiding the canoe with long bamboo poles. The men waved as we passed.

Diego said they were from the Yanomina village, not too much farther upriver.

We reached it twenty minutes later. A muddy bank with several canoes and rafts came into view, and a group of twenty-plus natives, mostly women and children, were scattered about. I expected most to be barely clothed, like the men seen earlier, but the kids all had on shorts and T-shirts, and the women wore brightly colored shawls. The women were doing laundry in the river, and the kids were kicking around a ball and laughing.

“The Yanomina,” Diego said again. “Their village is not too far from the river.”

“How many people live there?”

He considered the question, then said, “Sixty or seventy.”

The laundry and game both paused as we passed. The village women stared at us with little regard, but the children waved and jumped up and down. It probably wasn’t every day they saw someone on the river, and who knows how long it’d been since they’d seen a white face.

“Do the different tribes interact much?” I asked Diego as the Yanomina faded into the distance.

“Not too often, but every once in a while. Friendly tribes.”

This was the second time he used the word “friendly” to describe a tribe, and I asked, “Are there unfriendly tribes?”

“Yes. Deeper in the forest. Unfriendly. Very unfriendly. Headhunters. And cannibals.” I thought he was kidding about the last part, but the narrowing of his squinty eyes said otherwise.

Diego unzipped one of the aged military rucksacks near his feet and said, “That is why we have these.”

Inside the rucksack were three handguns, a Remington 870 shotgun, and two M16 military assault rifles, one with a laser scope.

Diego lifted out a matte-chrome pistol, pulled back the hammer, eliciting a soft click, and asked, “Have you ever shot a gun?”

The pistol was a Glock 22, not much different than the standard-issue Glock 19 that I’d carried for the four years I worked for the Seattle Police Department.

I replied, “No, but I’ve played a lot of laser tag.”

“Laser tag?”

Apparently, one of the big fads of my youth—and shamefully, something I did every Thursday well into my thirties—had yet to make it down to Bolivia. I told him I was joking, then attempted to explain laser tag to him, which I’m not sure he fully grasped.

“This sound like kid game,” he said.

“Yeah, that’s why I usually win.” Unless my nemesis, Lazer Crazer, has his karate class canceled.

“Actually, I have shot a gun,” I told him. “I used to be a homicide detective.”