Exploring Costa Rica with the Sierra Club

Text by Judy Herman  Photos by John Taylor

In December of 2022 I was privileged to experience the “Natural Highlights of Costa Rica” on a Sierra Club tour. It was a top notch tour of an astounding country. 

For a nation one-eighth the size of California, Costa Rica has a lot going for it: tremendous biodiversity, a high literacy rate, good education and healthcare, and a liberal democracy. 

How did it happen? Their 1949 constitution abolished the armed forces, freeing up funding for development and social services.

To explain why a country with only 0.03% of the world’s landmass is home to 500,000 species, or about 5% of the known species on Earth, we have to look back farther. Twenty million years ago the continents of North and South America were separate.Tectonic plates moving below the ocean caused volcanoes to arise, which eventually produced a chain of islands between the continents. Sediment accumulating between the islands resulted in a land bridge connecting North and South America for the first time in 150 million years. Species that had evolved on separate continents were then able to meet, resulting in enormous biodiversity. 

Diverse topography, from high mountains to river valleys and coastlines on both the Atlantic and Pacific, coupled with a tropical climate, gave rise to 12 distinct ecosystems, from tropical rainforests and cloud forests, to mangroves, wetlands and coral reefs and we saw many of them. These distinct habitats pushed more speciation. Plus, the centrally located country sees whales migrating from both Alaska and the Antarctic.

I knew Costa Rica was a birder’s paradise, boasting 941 species, but I also heard that of the total of 500,000 species 300,000 were insects and feared that 299,999 would be mosquitoes. But this mosquito magnet came through with only half a dozen bites and saw dazzling butterflies, stick insects and long lines of leaf cutter ants marching to their fungus farms. Thanks to Mario, our expert and eagle-eyed local guide, we also saw two- and three-toed sloths, several species of monkeys, agouti, coati, anteaters, caimans, poison-dart frogs, quetzals, scarlet macaws and many more wonders.

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