RIO DE JANEIRO -- Ecotourism is rarely as it's touted, even in the lush wilderness of Brazil.
The problem, of course, is access. The idea of nature, raw and unbridled, is largely incompatible with human development, especially developments built to accommodate urbanites seeking refuge from sprawl. Incursions on nature, however well meaning, alter habitats with the sound of the very first footfall.
Count me among the intruders.
Since moving to Rio de Janeiro last year, I've wandered north, south, and west of the metropolis on the Atlantic Ocean in search of the natural beauty that originally lured me to South America. I've seen equatorial beaches, subtropical woodlands, and the vast, verdant prairies of Brazil's interior.
Yet, I longed to go farther afield.
Not long ago, then, I journeyed to the central Amazon to visit the Mamirauá Institute for Sustainable Development, a research-based nature reserve in Brazil's northwest corner. Halfway along the river's course (its source in the Peruvian Andes and its mouth on the Atlantic are each 1,000 miles away) the reserve offers one of the most authentic Amazon visits available to the basic traveler.
Founded in the 1980s as a haven to study the uacari, a red-faced, white-haired monkey native only to Mamirauá, the reserve in recent years began hosting travelers, and now offers three- or four-day packages to groups of no more than 20.
Whatever guilt I felt about trampling through the area was assuaged by knowledge that tourism adds to a budget mostly reliant on grants. It also aids the nearby communities of caboclas, river dwellers of mixed Indian-Portuguese ancestry, many of whom work in the program supplementing traditional livelihoods like fishing and agriculture with the income afforded by tourism.
Because of its scientific mission, and by dint of its isolation, the reserve is the most actively environmental destination I have visited. Water for the guest lodges -- floating cabins tethered to the river bottom -- is pumped from under the floorboards, filtered after use, and recycled back into the river. Light and hot water, a surprise, are powered by rooftop solar panels.
Meals are limited to food native to the region, mostly fish, fresh fruits and vegetables, and poultry raised nearby. Even leftovers are recycled in the surrounding water: A couple of resident caimans snap up whatever the piranhas don't devour first.
Landscape is reason enough to visit. The reserve covers 4,300 square miles (half the size of New Hampshire) of terrain classified as ''flooded forest," an ecosystem dictated by at least three months of annual flooding. Trees that tower over riverbanks in October appear mere bushes half a year later.
The true draw, however, is the wildlife. Wildcats, birds, and monkeys -- all animals that can climb and swim to safety during floods --live above waters teeming with fish, amphibians, and reptiles. Mammals that live in water, including river manatees and freshwater dolphins, navigate the submerged woodland of tree trunks, roots, and vines that also host piranha and pirarucu (one of the planet's largest freshwater fish), as well as turtles, anacondas, and caimans.
Three friends joined me for the journey. Here's a breakdown of our four-day stay.
Tuesday arrival. One of the charms of Mamirauá is its remoteness. But that means it's hard to get to.
From Rio we flew five hours to Manaus, the biggest city in the region and the hub of most Amazon travel. The next morning we flew to Tefe, 415 miles upstream, where staff members from the reserve met us and eight other visitors and drove us to the town's steamy, litter-strewn port.
There, two launches awaited for a further two-hour trip upstream. As we stepped aboard, Paulo, one of the guides, said: ''Last chance to make a phone call. From here on, there's only radio."
The launches sped into the Amazon channel, here called Solimões. Absorbing my first closeup view of the river (its breadth inspires awe), we overtook dozens of other vessels, most of them traditional Amazonian passenger boats. With their colorful paint and hammocks, satellite dishes and clotheslines, the boats resembled misfit, tropical descendants of old Mississippi steamers.
An hour later, we turned off the channel and headed into the flooded forest, finally reaching the reserve at 3 in the afternoon.
The lodges, a string of five huts and a central guest house, float at the edge of a placid inlet. Greeting us at the dock, the lodge staff and our guides led a round of introductions and then showed us to our cabins -- spartan but nicely decorated rooms with patios. Blue window shutters and etchings of area wildlife -- a manatee in our cabin, a fish in a neighbor's -- adorned otherwise bare wooden walls. In addition to a wooden shelf and a small corner table, the room's only other furnishings were twin beds with between them a reading table, and on it a single wax candle.
Lunch -- catfish, rice, beans, and passion fruit mousse for dessert -- was the first of many satisfying meals. While the ingredients rarely varied, the cooks, who were cabocla women, were inventive. The same fish we ate stewed at lunchtime, for example, serves as the base for a dinner casserole.
After lunch the guides broke us into pairs for orientation in canoes. In short order, we spotted a sloth, a giant lizard, and all sorts of colorful birds. Still, I worried that two of my friends, metropolitan Europeans vacationing from winter, might soon long for civilization.
As their canoe pulled alongside mine on our way back to the lodges, I asked them what they had seen.
''Some dudes," replied Philip. ''I'm not sure what they were." This is the man, a Russian, who had told me before leaving Rio: ''I'm not really that into wildlife."
Later, watching the sun set from our patio hammocks, Konstantin, a sardonic German, took a sip of whiskey and said: ''This really is the end of the earth."
Wednesday paw prints and piranha. If Konstantin went to bed skeptical, he arose even more so. He had not sprayed insect repellent in his room before bed, and mosquitoes, coupled with jumping fish and noises from other creatures, kept him awake.
''It's as close to hell as I've ever been," he said, ignorant that tonight would be even worse: A bat, harmless in the end, would brush past his balding head.
After breakfast -- melon, eggs, toast, and coffee -- we split into groups and headed for a hike of area trails. The boat ride there yielded views of further wildlife: howler monkeys and hawks, then a group of uacari, their red faces visible high in the branches.
Vegetation along the trails is sparse for Amazon jungle. Undergrowth succumbs to the flooding, the marks of which stain the bark of trees far overhead.
Halfway through the hike, Nelson, a guide, pointed at the ground: a jaguar print.
''They use the trails at night," he said. ''It helps them stalk with stealth."
The cat, of course, was long gone, but later in the morning we got close to another kind of predator: a piranha.
When we used branches for fishing poles and strips of other fish as bait, the toothy creatures hit the lines at once. Patricia pulled the first of many from the water (we returned them all immediately, except one we used for additional bait) and Nelson demonstrated the fish's instinct. Securing it with one hand, he slipped a reed into its mouth: The piranha chomped the stalk in a series of quick, crisp bites.
That evening, we visited Vila Alencar, a community of 27 families downstream. While their children tagged along with pet dogs and a friendly spider monkey, the adults showed us the village and orchards of banana, palms, and manioc trees. The houses, built on stilts, are slender multistory cabins; during flooding, residents move upstairs.
Walking along a trail the river swallows in the wet season, João, a resident of the village and an employee of the lodge, said the settlement's boats are their only conduit to the rest of region. A canoe and a motorboat ferry villagers to Tefe and other towns where they sell crops and purchase provisions.
''Other communities like ours disappeared," he said, explaining how the lodge bolsters the precarious local economy. He bent over and grabbed a palm branch that, until recently, held bunches of acai, a violet-colored berry mashed and eaten as a thick, tart pulp. ''This, for instance, provided your dessert for tomorrow."
Night fell for the journey home and the guides shined flashlights from the boats. The eyes of caimans, reptiles similar to alligators, shone on the water like embers.
Thursday, Friday dolphins, porcupines, and conversion. We spent the next two days on the trails and in the canoes.
The jaguar remained elusive, if nearby. One morning, Wanderley, a guide, spotted a heap of droppings on the trail, strands of gray hair melded into the feces.
''That's a jaguar's," he said, ''It ate a sloth."
That night, as the boats returned to the lodges, it rained.
Jacob, a young Dane traveling before starting college, bailed water from his boat. ''Now I understand why it's the flooded forest," joked his travelmate, another young Dane also named Jacob.
Though it rained through the night, the weather didn't dampen our moods. Even Konstantin -- had the bat knocked some sense into him? -- appeared to be enjoying himself.
On the last day, Philip spied a porcupine among some branches and he, too, grew enthusiastic. ''I see how people get into this," he acknowledged, binoculars still in hand. ''That animal makes the trip."
How a prickly rodent is more intriguing than caimans and sloths I didn't quite understand. As the one who led us away from the beaches and bars of Rio, though, I was happy he had come around.
Paulo Prada is a freelance writer in Brazil. He can be reached at email@example.com.