Costa Rica Confirms Recovery of Significant Pleistocene Megafauna Fossils

Costa Rican authorities formally confirmed in mid-February 2026 the recovery of significant fossil specimens belonging to the giant sloth, Eremotherium, and the mastodon, Cuvieronius. These remains are provisionally dated to the period between 10,000 and 40,000 years ago, placing them within the Pleistocene epoch, a time characterized by the presence of Earth's largest land mammals. The discovery, located at a confidential site within the Cartago province of central Costa Rica, is already recognized as one of the most consequential paleontological events for the nation in decades.

The Ministry of Culture and Youth issued a statement highlighting that this exceptional find constitutes a "significant contribution to national scientific knowledge." This recovery substantially enriches the paleontological holdings of the National Museum of Costa Rica (MNCR) and elevates the country's standing in regional scientific endeavors concerning extinct megafauna. The investigation began after a private property owner reported the suspected presence of ancient biological material, leading to a technical assessment by the MNCR team that verified the existence of the Pleistocene megafauna pieces and triggered a methodical recovery protocol.

As of February 18, 2026, the systematic recovery process has yielded a total of 49 distinct fossil pieces across 13 separate excavation and rescue phases. Notable recovered artifacts include a complete mastodon tusk measuring 1.60 meters in length, an additional tusk fragment, several vertebrae, a femur, various phalanges, and ribs, all currently undergoing detailed laboratory analysis. Preliminary geological and sedimentation analyses are crucial for establishing the precise age range of 10,000 to 40,000 years for both the Cuvieronius and Eremotherium remains.

The technical research contingent at the site comprises 12 specialized professionals in geology, archaeology, and biology, supported by University of Costa Rica interns. The recovery efforts are directed by geologist Joanna Méndez Herrera, affiliated with the MNCR's Department of Natural History, with logistical support from cultural heritage conservation specialists. The team has engaged in international consultation with paleontologist Lucas Spencer from the New Mexico Museum of Natural History and Costa Rican geologist Guillermo Alvarado Induni.

The context of this discovery relates to the Great American Biotic Interchange (GABI), the paleozoogeographic event involving fauna migration between North and South America following the formation of the Isthmus of Panama approximately 2.7 million years ago. The presence of both Cuvieronius and Eremotherium in Central America is significant as the region served as a vital corridor during the GABI. Cuvieronius, an elephant relative, reached shoulder heights of 2.3 meters and massed around 3.5 tonnes before its extinction near 12,000 years ago. Eremotherium, a terrestrial sloth, could tower up to 6 meters and weigh approximately 4 tons.

The Late Pleistocene extinction event, which saw the disappearance of most of the world's megafauna, remains a major focus of study, with the Americas experiencing severe losses around 13,000 years ago amid debate over causes, including human overpredation and climatic shifts. The MNCR's findings provide tangible local data to help reconstruct the ecosystems and migratory patterns of these massive creatures. Following the announcement, Minister of Culture and Youth Jorge Rodríguez Vives directed the MNCR to begin planning a dedicated, permanent exhibition hall to house the national paleontological collection, including these new fossils. The exact excavation coordinates are being maintained as confidential to ensure specimen security.