New capybara fossil changes the forecast for the ancient Atacama region

Capybaras like their habitats wet. These large rodents thrive in low-elevation wetlands, migrating along creeks and rivers to nibble on foliage and flowers. That’s why researchers were surprised to find an 8.8 million-year-old fossilized capybara tooth in northern Chile’s Atacama Desert, one of the driest regions on Earth. In a paper published Sept. 5 in Scientific Reports, researchers postulate that the Atacama Desert must have had a wetter climate during the Miocene epoch, based on this discovery. This is the first time a capybara species has ever been seen in the Atacama region of Chile – today these creatures reside in the marshy lowlands across Venezuela, Colombia, Argentina and Uruguay. Researchers had at one time assumed that the Andean mountain chain on the eastern side of Chile would have prevented these short-legged rodents from ever entering the Atacama region. With this discovery, the authors propose that capybaras were able to follow a wetland trail along the northern part of South America, trekking from Bolivia to Peru into northern Chile. In addition to capybaras, the ancient Atacama region also likely had palms and other flowering plants, according to plant fossils analyzed by a UW scientist for the study. These findings challenge the idea that the Atacama was just always a desert, and can help researchers better understand how shifts in climate can drastically affect the environment.