Want to see a monkey in its natural habitat? Spot a tiny brightly colored poison dart frog along a trail? Stand beneath a giant tropical tree loaded with epiphytes? See a big blue butterfly too beautiful to believe? Would you like to observe toucans, quetzals, and scarlet macaws? How about a crocodile basking on the riverbank or a dolphin arching from the sea? Do all this and more in Costa Rica.

The chance for a close encounter of the natural kind with the tropical biodiversity found in this small, friendly country lures tens of thousands of visitors each year. And they must like what they find because many return again and again to explore the varied habitats: rain forest, dry forest, cloud forest, oak forest, high-mountain paramo, and wetland, mangrove, and other aquatic habitats.

What is out there? More than 850 species of birds, 209 mammal species, 13,000 plant species (including 1,500 trees and 1,400 orchids), 220 species of reptiles, and 163 species of amphibians. As for the usually diminutive world of arthropods--creatures with segmented bodies and jointed limbs, such as insects, spiders, and crabs--look out: more than 365,000 weird and wonderful species have been identified so far.

Many of the habitats where all this life flourishes are under protective status, with about 16 percent of the country in more than 30 national parks, wildlife refuges, and biological reserves that are open to the public. Another 16 percent is in forest reserves, Indian reserves, and protected zones. In addition, individuals have established reserves for conservation purposes.

So, there are protected habitats, more than half a million known species doing their thing in the ecosystem, and tens of thousands of human visitors who hope to watch them doing it. How can this play out in harmony? Ecotourism offers sustainable strategies.