It’s been a mystery hiding in plain sight. Researchers working with tiny worms called Caenorhabditis elegans—a common lab organism used to study basic principles of biology—know not to raise the temperature above about 80 degrees Fahrenheit because the worms start to die. Yet some populations of C. elegans in the wild thrive above that temperature, such as those that live in Athens, Georgia, and Ceres, South Africa. The worms belong to the same species, so why do they have such different tolerances to heat?
