Incendiamoeba cascadensis can divide at 145.4°F, remain active at 147.2°F and recover after brief exposure to 158°F. The amoeba, found in a neutral hot spring at Lassen Volcanic National Park, sets the known heat record for a eukaryote—the domain that includes animals, plants and fungi. The research appeared in Cell on September 22. Reuters’ report on the study
It survives by reshaping itself, forming a protective layer and activating unusually extensive protein-maintenance and DNA-repair machinery. The ecological detail is delightful: at these temperatures it can feed on heat-adapted bacteria with little competition from other predators. That makes it a top predator in a world measured in microns. The astrobiology implications should be kept in proportion—hot terrestrial springs are not proof of extraterrestrial life—but the organism widens the experimentally observed range in which complex cellular machinery can still function.