As rain was our companion on earlier journeys, now our companion is fire. We had welcomed the rain, flooding the world with its brimming abundance; but though we dread the fires, we cannot escape them. Some days, on the horizon at Curucu, there are four or five columns of smoke; some days the air is leaden with it, pressing the river flat as quicksilver. One night, fire had nearly come into Alter do Chao itself, so close we could feel its gnawing heat. Always, somewhere, there is fire or smoke, insistent reminders of the greed consuming the world.

As we head to Curucu this morning, we see three big fires to the west, and the air is hazy. Only in the river can I find respite from the burning. As Dianne unpacks her photo gear, I swim out to meet the first fins. I breaststroke slowly and they come to me: first, the mother and baby; one very large pink adult; two big grays.

I am surrounded, but I do not know this; Dianne, taking photos from the top of the Gigante, later tells me there were dolphins all around me. Two pinkish tucuxis joined the group, one with a slash across the dorsal. For three-quarters of an hour, there was not one minute that I could not see a dolphin at eye level. As they surfaced, it seemed I could feel their glance. Or perhaps it was their sonar. Later, I would learn that people who work with marine dolphins say they feel the animals "sounding" them, throwing out trains of ultrasonic clicks created by moving muscles in the melon, and waiting for their echo to return. Their sonar retrieves a three-dimensional soundscape, a sonogram, of what lies ahead of them; the boto, with its flexible neck, can turn the head in a wide arc and obtain an exceptionally broad sounding. One researcher, Bill Langbauer at the Pittsburgh Zoo, told me when the sound waves hit him, it feels like humming with your teeth clenched.

I always save the moment I enter the water for them. Dianne and I wait at the edge of the river, and I do not swim until the dolphins come. I spot one fin, close, and give my body to the water. Dianne stays at the edge of the river, or sometimes on the roof of the Gigante, photographing. She is a strong swimmer, but her father was a sea captain; those who know water most intimately, I have found, tend to more wisely respect its dangers. But I lose myself utterly in the water, like a soul leaving a body. Now that we have come here daily for a week, we recognize seven individuals: there are two medium-sized grays, the bowler-hatted businessmen. In fact, Dianne knows an Englishman who owns an actual bowler hat, and we named one of the dolphins after him -- David. The other we named Gary, whose distinctive rain hat had been the envy of everyone on my second trip to Peru. One very large gray dolphin we name after Vera. A very large pink one we call Valentino. Another is gray with pink lips, and we name him that -- Pink Lips. And occasionally we spot a mother and baby. It is nearing Christmastime, so we call them Mary and Jesus. Pink fins, gray bellies, the bulbous soft heads; I so wish I could touch them. I can feel the currents their bodies make as they slip through the water. One day, I look down into the water beneath me and see a large gray form swim under my feet. All but immersed in these clear blue waters, I feel as if embraced by paradise.

But that was inside an aquarium tank. I swim inside of living water, and always I feel the water humming, charged with life like the blood in my veins. I cannot feel the botos sound me, but surely they are doing so. They can see through me, as God does. They do not touch me, but their soundings penetrate my flesh. They know my stomach is full and my womb is empty; they can see the faulty mitral valve in my heart. And yet, even possessed of this astonishing sonar, they still pull their sleek faces out of the water to look at my face. Why would my face be important to them? They can recognize me by the other nine-tenths of my body beneath the water. Yet they look into my face again and again. They must know we humans wear our souls on our faces. Perhaps, to them, too, a meeting is more profound when it is face-to-face.

And what do I know of them? I only know the sex of one -- the mother with her baby. I do not know how long they have lived. I do not know how far they travel. I do not know if this group always stays together, or only comes together here to investigate the pale, terrestrial stranger who hangs in the column of water before them.

But somehow I am not frustrated that I will never learn the answers; this is not, I now know, what they have to teach me. Already, their kind had shown me so much: the botos brought me to Manaus, the impossible Paris in the Amazon; the botos drew me to the Meeting of the Waters. The botos drew me to Tamshiyacu-Tahuayo, and to Mamirauá, and now, to the clear waters here. Throughout these four journeys in the Amazon, I had followed them, though not in the way I had originally planned. For the verb "to follow" carries many meanings, most of which I hadn't been aware of when I had decided to follow them. To proceed behind them, to go after them in pursuit, as I had envisioned when I'd hoped to trace their migration, was merely one way of following. Other meanings are more subtle and profound: to be guided by; to comply with; to watch or observe closely; to accept the guidance, command, or leadership of; to come after in time; to grasp the meaning or logic of. And so, without chasing them along a migration, without a single hit on Vera's telemetry, I had followed them nonetheless. In Tamshiyacu-Tahuayo, I had followed them to the spirit realm, where shamans commune with the powers of the plants and visit the Encante; with Gary, I had followed them back through time. At Mamirauá, they had taken me to the heart of the Amazon's modern conservation dilemma. And now, I followed them still, hanging in the water before them, ready to receive their gifts and their guidance.