WILDEST DREAMS

The rainforests around Arenal Volcano are alive with capuchin monkeys and caimans, tanagers and tree frogs. Amy Waldman visits this hotbed of biodiversity and finds herself face-to-face with Costa Rica's wild side.

- Amy Waldman

IF, AS IT'S OFTEN SAID, we are each the star of our own movie, isn't the same true for every creature searching for food, a mate, or a home? They're at the center of their existences, just as we are at ours. There are countless overlapping films, streaming at all times.

Costa Rica, which is rightly renowned for its biodiversity, is a good place to watch some of them. The country packs 12 ecosystems and half a million species into its 20,000 square miles. Over half its landmass is forest - a celebrated reversal from the 1990s, when deforestation had eliminated more than three-quarters of the original forest cover. Which makes it the perfect setting to explore the lives of other species, and decenter your own.

When my husband, Alex, and I visited in early June, we got our first taste of this sensation on the nearly three-hour drive north from Juan Santamaría International Airport in San José to our destination, Arenal Volcano National Park. Along the winding route, it was human dominion all the way - city and slum, highways and trucks, fields for crops or livestock until we hit the rainforest. Walls of green, designed for neither our comfort nor our sustenance, pressed in from both sides. It was as if we had turned the page of a script to find we were extras, not stars.

The park is named for the volcano at its heart, itself a humbling spectacle. Arenal is some 7,000 years old and about 5,300 feet high. Its last major eruption was in 1968; lava flows continued for decades after that. It no longer spews molten rock, but it still vents steam. While Arenal is often obscured by clouds, we got lucky: for five days it was our constant companion.