One of the principal sources of Costa Rica's biodiversity is that the country, together with the land now considered Panama, formed a bridge connecting the North and South American continents approximately three to five million years ago.
Jedan od glavnih uzroka biološke raznolikosti Kostarike je činjenica, da ona zajedno s Panamom, čini "most" koji povezuje sjever i jug američkih kontinenata i to još od prije oko 3-5 milijuna godina.