Sabrina had a constant smile. I didn't ask, but I wondered if she reflected back at all to her years in prison, and each day filled with drab gray surroundings. If it hadn't been for the lenient judge, she could still be there today.

We saw enormous river turtles, and on occasion Paulo would point out a caiman sunning itself on shore. A couple of times we looked down in the water to see bulbous eyes peering back at us.

"What are those?" I asked Paulo.

"Baby Caimans," he answered. "Eyes and snout maybe all you ever see."

Late in the second afternoon on the river, Paulo called to us from the other side of the boat and frantically motioned for us to join him. When we got there he pointed down at an enormous shape passing us in the water. It had to be fifteen or twenty feet long and five feet wide.

"Manatee," said Paulo. "Rare to see. People kill them for skin and oil. Once there were many in the river. No longer."

The wildlife we weren't happy to encounter were the mosquitos and black flies. They came out in force in the evening and we had to use bug spray and cover up. But somehow, it was all part of the experience—one I could have done without, I suppose.

Luis and Paulo took turns operating the boat and also took turns resting. At night, however, we stopped for a few hours so that they could both catch up on some sleep. It was the third night of our journey and Luis had just turned off the engines. Every time he did that at night, we almost collapsed in appreciation for the silence. We had gotten used to the constant throb of the engines, but the silence was heavenly. In reality, it wasn't silent. The jabbering of the birds and the monkeys never let us forget the paradise we had stepped into.

This particular night, though, there was a different sound—a cry. No, not even a cry, really. It was the most chilling sound I had ever heard in my life. It came from the jungle—not very deep in the jungle though. At the sound of it, it seemed like all the other jungle noises came to a sudden stop. Paulo got up from his hammock on deck and joined us at the rail.

"Jaguar," he whispered. "You are very lucky to hear that."

One more time the cry came, longer than the first time. And then it stopped. Eventually the other jungle noises resumed and all was back to normal. But it took many minutes for the goose bumps on my arms to disappear.

"I think that was the most amazing thing I've ever heard," Sabrina said quietly, almost reverently. "It was the epitome of nature at its most spectacular—of life like I've never heard it." There was nothing more to be said.

Meals aboard the boat were simple, but tasty. They usually consisted of some combination of rice, beans, chicken, and local vegetables. Dessert was fruit or sweet bread. Paulo was the official cook and took great delight in our reactions to his meals.