More than 400 penguins, most of them only babies, have been found dead on the tropical beaches of Rio de Janeiro over the past 2 months—an unusual and as-yet unexplained phenomenon, the AP reports. While Brazil’s beaches are no stranger to the occasional penguin—dead or otherwise—the sudden flood is stumping experts.
One veterinarian believes overfishing may have driven the penguins further from shore, and into strong ocean currents. Others suggest that increased pollution may be responsible for killing the birds. Still others suggest that global warming is making penguins sick, while simultaneously intensifying ocean currents.