Venta River
The Sima de las Cotorras belongs to a Karst topography system, based on the folding, fracturing and erosion of limestone. This particular system is defined by its drainage system, with the La Venta River on the surface and the main underground river being El Paraíso. Despite its proximity to the Pacific, drainage is towards the Gulf of Mexico. Most of this ecological system is covered by the El Ocote Biosphere Reserve.