Ometepe is an island formed by two volcanoes rising from Lake Nicaragua in the Republic of Nicaragua. Its name derives from the Nahuatl words ome (two) and tepetl (mountain), meaning two mountains. It is the largest island in Lake Nicaragua.
The two volcanoes of Concepción and Maderas are joined by a low isthmus to form one island in the shape of an hourglass. Ometepe has an area of 276 km². It is 31 km long and 5 to 10 km wide. The island has an economy based on livestock, agriculture, and tourism. Plantains are the major crop.
Ometepe Island is generally included within the archaeological area of “Greater Nicoya,” which also encompasses the Rivas area on the lake shore and descends into Costa Rican Nicoya Peninsula. Due to deposits of volcanic ash over millennia, the soil is very fertile, allowing constant planting without fallowing. This rich environment has allowed the island to be continuously inhabited since the Dinarte phase (ca. 2000 B.C. – 500 B.C.).
Ometepe harbors large populations of the white-faced Capuchin monkey, also called white-headed Capuchin, (Cebus capucinus) and populations of the mantled howler monkey (Alouatta palliata). Efforts are being made to study and protect these animals. The Ometepe Biological Field School is situated on the Maderas side of the island. Here, students and scientists from all over the World come to study the unique flora and fauna of the area. The lake surrounding Ometepe harbors many species of aquatic animals, notably the Nicaragua shark which until recently was thought to be a unique species of freshwater shark but has since been shown to be continuous with ocean populations.
Small populations of spider monkeys (Ateles s.) inhabit very small islands within Lake Nicaragua. These populations exist solely due to humans and many of the local fishermen routinely stop by to feed these troops. The local form of the rice rat Oryzomys couesi is distinctive and may represent a separate subspecies.