Surviving the Extremes: A Doctor's Journey to the Limits of Human Endurance by Kenneth Kamler

other repositories of its genes, that would be fine from the genes’ perspective; they come out ahead. The closer the sacrificing animal’s genes are to the animal it is sacrificing itself for, the more effectively the system works; and in fact, the impulse for altruism is strongest for the immediate family, then progressively weaker for other relatives, others of the same ethnic group, and others of the same species.
    The system has worked well for the small poison-dart frog. Antonio, like other Amazon predators, eats only large frogs, and even then only after removing the skin. He said he saves the small beautifully colored ones he catches to make poison-tipped darts for his blowgun. Though so far I hadn’t seen one, I knew I was in blowgun territory. A blowgun is a hollow bamboo tube with a splinter of wood placed inside one end. A sharp blast of air propels the splinter out the other end like a rocket. The blowgun is made entirely from local ingredients, but I thought it might now be obsolete. I told Antonio I was surprised he still used one.
    “I like hunting that way,” he replied. “Though using a shotgun is easier.”
    The trail seemed to come to an abrupt dead end. Ahead of us was a wall of small plants and bushes, as well as an overturned tree whose base was taller than I was. The tree had fallen recently, leaving a hole in the canopy, but already the sunlight that penetrated through that hole had stimulated enough new growth to obliterate the trail. We worked our way around it, stepping over some branches and limboing under some others, moving through a “no-touch” forest. I couldn’tplace my hands anywhere for balance—leaves have itchy coatings, branches have thorns, and barks have biting ants. I was constantly afraid to anger some insect, make a snake think it was under attack, or inadvertently grab a poison-dart frog.
    The temperature and humidity had been rising steadily; breathing in was like inhaling the exhaust from a Laundromat. I wasn’t tired, but I was sweating. My shirt couldn’t have been wetter had I swam here. Antonio must have thought I needed a drink and a snack. He eyed a thin bamboolike canawaska vine and tapped it with his machete. Deciding he liked the sound, he chopped out a section that included two knots. He tucked it under his arm as we went on a little farther. In a small clearing, we stopped for a break but I didn’t sit down. I noticed Antonio remained standing as well. The canawaska section was a hollow tube sealed at both ends by the knots. Antonio cut into one end and a clear liquid ran out. He offered it to me first, but when I hesitated he took a drink himself. I soon followed. It was fresh-tasting water.
    While I drank from the canteen he had made, he stepped off the trail and, with three or four strokes, hacked down a 60-foot palm tree roughly 2 feet in diameter. He chopped out a section of the trunk near the top and split it open. He took out the center and then split that open. Inside were little white shoots. He peeled them and gave me some. They were hearts of palm.
    Antonio was an opportunistic hunter. He spotted a tree with lemony-looking fruits just beginning to ripen. With a stick, he beat the branches until a good one fell, then he cut it up and shared it with me. Antonio really enjoyed it, and went back for a second one. The fruit had a lot of uses, he informed me—as a tea it brought down fevers, and the women used it as a contraceptive. It was a sweet-tasting dessert, but it had a lot of pits. I spit mine out; Antonio put his in his pouch.
    He was completely at ease and relaxed here. The jungle was Antonio’s home. Although he didn’t have much speed or strength by animal standards, he had knowledge; and knowledge was enough to provide him with a comfortable life.
    Lunch over, Antonio nimbly and quickly wove a basket out ofleaves and vines and placed it in the clearing. As we left, it started to rain—a real downpour from the sound of it, but I