Altitude causes these differences, controlling humidity and temperature. Rain shadow is another major factor,leaving the Atlantic side of Costa Rica generally wetter. In fact, because Central America lies at the crossroads of major climatic regions, it holds over half of the world's flora and fauna species, most of which have not even been discovered. In the rainforest it's dark and thick with trees hundreds of feet tall. And every plant here has a system for soaking water up as quickly as possible, often in the form of porous roots .
Some plants even act like pitchers and trap water in their funnel shaped foliage.
These plants attract many animals to them in search of water themselves. As for the animals, they spend most of their time either hunting or hiding from other hunters, so they can be very difficult to spot in the dim light. That's why it's best to hire a guide if you want to hike through the rainforest. Their well-trained eyes can spot things you never knew were there. Akin to the Costa Rican rainforest is the cloud forest , hugging the slopes of the country's many mountain ranges.