Guide to Costa Rica: Osa Peninsula
Stretching over the western flank of the Osa Peninsula, the Corcovado National Park is, according to National Geographic Magazine, the most biologically diverse region in the world.
Boasting the largest remaining stretch of tropical lowland forest on the planet, the park is home to thirteen major ecosystems, 140 species of mammal, 400 bird species and 116 amphibian and reptile species.
Osa also harbours the largest population of Scarlet Macaw in Central America, more than 100 species of butterflies and six of large cat, including the elusive jaguar.
In layman's terms, this astounding biodiversity means you can expect some truly fantastic wildlife viewing. Within a few days it is not unusual to spot Howler, White-faced Capuchin and Spider monkeys, two and three-toed sloth and Silky Anteater, not to mention a variety of colourful parrots, toucans and hummingbirds.
The marine life rivals that of the forest and the Isla del Caño Biological Reserve, 20km off the coast of the peninsula, is a particular hotspot for scuba divers or snorkelers.
The water here is clear and calm, perfect conditions to see the stingrays, manta rays, moray eels, barracudas and variety of other fish and shark species that inhabit the reserve.
If you don't want to get your hair wet a boat trip across the Golfo Dulce or to Caño Island provides its own excitements, with pods of dolphins playing chase in the wake. From December to April the park also falls into the migratory path of humpback whales.