By Amy Graff

"Shhh, follow me," whispered our guide, Rolando Mora, as he led my husband and me tiptoeing off the trail into the thick of Costa Rica's Corcovado National Park.

"Miren," said Rolando, pointing up.

In the treetops that towered above a mess of Tarzan vines, a dozen spider monkeys were using their hands, tails, and feet to swing from branch to branch. Seeing the monkeys playing wildly was like spotting a deer in a grassy meadow after backpacking deep into the forest; we were observing them in the raw wilderness, practically undisturbed by mankind. Later that afternoon, Mora's keen eyes and ears picked out a white-faced monkey carrying a baby on its back, a thumbnail-sized frog with an ear-piercing ribbit, and six scarlet macaws flying from palm tree to palm tree.

At the end of the day, we sped back by motorboat taxi to our lodging on nearby Drake Bay. Sir Francis Drake purportedly dropped anchor here in 1579, and it's a place he'd still recognize: The town consists of a general store or two and several small, bungalow-style lodges—no telephone poles, no power lines, no restaurants, no trinket shops.

We stayed at the home of Fred Maschmeier, a fisherman whose main gig is taking tourists out in his 26-foot sportfishing boat. Early evening found us on his front porch, sipping fresh-squeezed star fruit juice as the setting sun turned the bay to luscious reds, oranges, and yellows. At dinner, Fred miraculously pulled a baked chicken and scalloped potatoes from a propane-powered oven. We dined by candlelight and listened to his stories of the early days when he fished the Florida Keys. We fell asleep dog-earing our guidebooks by solar-powered light.

We came to this destination of the moment in search of unspoiled territory—a rarity in a country where international visitors have gone from 300,000 in 1980 to more than 1 million in 1999. Most of these travelers are drawn to Costa Rica by both the country's rich biodiversity and its reputation as "the Switzerland of Central America," an island of tranquillity in a sea of political instability. As for us, we came to see how the country was coping with the masses of tourists, the tangle of new roads, and the influx of foreign hotel owners. And to see if we could find a pristine nook in the jungle.

Drake Bay fulfilled our quest for untrammeled wilderness. But getting to this ecologically rich area was not easy. We spent a small fortune to rent a four-wheel-drive vehicle, and then drove more than six hours on a pothole-laden road to the port in the dusty town of Sierpe, finally arriving in Drake by boat taxi. Our only other options were to pay for a commercial flight or pack ourselves into crowded public buses that are notoriously late. Despite the hassle, we realized that this inaccessibility is what prevents throngs of tourists from degrading the environment. In Costa Rica, if you want to walk on a surreally deserted beach or witness wildlife in its natural habitat, you need patience and a sense of adventure—or money. If you visit the more easily accessed destinations, expect to share your monkey sightings with camera-carrying hordes—as we did at Manuel Antonio National Park earlier in our trip.

Capuchin monkeys are the most inquisitive of Central American simians.

To reach Manuel Antonio from the capital city of San José, we joined a caravan of tour buses on the winding road to the coastal town of Quepos, which borders the park. Driving through the forested hills, we were bombarded by hotel signs shouting CNN NEWS SPORTS, INTERNET ACCESS, and CINEMA THX. After finding a parking space outside the park, we waited in line to buy our passes for the day.

With its postcard-perfect setting, where white sandy beaches meet verdant jungle teeming with wildlife, Manuel Antonio would seem to epitomize everything tourists come to Costa Rica to see. In fact, it's one of the country's most popular attractions. Thanks to a limit established four years ago on the number of daily visitors allowed in the park, there were only about 800 people in the park that day. But with only 3.5 miles of trails, it was difficult to find a moment of solitude. What we did find was graffiti on tree trunks and litter on the trails. The damage done to the natural environment within the 1,700-acre park also extended to its indigenous inhabitants. It was in Manuel Antonio that we had our closest encounters with wildlife—monkeys, sloths, and coatis—but local tour guide Robert Foster told us this was because the area outside the park has become so built up that the animals are trapped. The national park's prized population of white-faced squirrel monkeys is declining because the migration corridors necessary for them to breed have been cut off.

Our up-close encounters with these white-faced monkeys were also the result of the human food tourists bring into the park; a study has revealed that nearly half of the monkeys' diet now comes from garbage cans, scraps left on picnic tables, and visitors' hands.

"I have seen things here that I have never seen at other parks," said Foster, who's been leading tours in Costa Rica for seven years. "I have seen little girls giving their hands to monkeys. Soon you're going to see the monkeys wearing Nikes."

Manuel Antonio is paradigmatic of the destruction tourism can do to a natural area. Admirably, 27 percent of Costa Rica is designated as national park, but due to the lack of regulation, the land outside the parks is often besieged by development. When new hotels, restaurants, and outfitters attract tourists, nearby parks, such as Manuel Antonio, become more like city zoos than preserved settings.

The glory days of ecotourism in Costa Rica are dwindling if this is the ultimate fate of any area that's situated on a paved road. Every year, remote locations are transformed into major tourist attractions by new roads, such as a recently opened section of the Costanera Sur Highway, which runs along the coast from Dominical to the Osa Peninsula. Currently, the majority of the Costanera Sur remains unpaved, but locals anticipate a pothole-free highway within the next 10 years.

A hiker is greeted by one of dozens of butterflies in Corcovado.

Foreigners have flocked to the area to open hotels, talking excitedly about the luxuries increased access will allow: satellite TV in poolside bars, reservations over the public telephone, Web sites. But many of these new hotel owners also have a lot to say about the environment.

Woody Dyer, the American owner of the Bella Vista Ranch & Lodge, is one of them.

Woody's rustic wooden lodge is located high above beachside Dominical in the Escaleras, a mountainous region that kisses a skinny strip of coastline. Development in the area is on the verge of booming; foreigners have discovered the sweeping vistas, and vacation homes and tourist accommodations dapple the mountainside. Sitting in an open-air room that takes in this view, Woody told us about the influx of tourists and hotels he anticipates in the future—and about the pool he plans to build this summer to prepare for the competition for hotel guests. We envisioned new structures denuding the sylvan mountainside, but Woody painted a different picture. He argued that today's developers are smarter.

"They have an environmental consciousness," the Louisiana native said.

When Woody first came to the area, more than 20 years ago, the Escaleras's primary rainforest had been cut down to make way for pastureland—thanks to the U.S. dollars loaned to Costa Rican ranchers in the 1960s to stimulate beef production. But when people recently started purchasing land, they revegetated their landholdings.

"They brought the rainforest back," Woody said. "Now the animals are returning. I'm just waiting to see my first scarlet macaw. They left the area long ago, but they'll be back."

From the porch, we watched a storm sweep in from the sea; soggy clouds hugged the mountainside. The rest of the day we spent reading in our room as the rain pounded overhead. When we woke the next morning, the day was crystal clear. Clumsy toucans played in the trees, consistently missing their landings due to their awkwardly long beaks. As we watched their antics, we couldn't help wondering whether these birds would still be a part of the Escaleras experience 10 years from now, when the mountainside will inevitably be home to many more hotels. Thanks to eco-minded people like Woody, we felt a sense of hope—for the toucans and for Costa Rica.