High above the larch forests of northeastern Siberia, where the Verkhoyansk Range cuts a jagged line against the sub-arctic sky, lies one of the most hostile terrestrial environments on Earth. This is Yakutia, a region famous for record-shattering winter temperatures that plunge below minus 60 degrees Celsius. Yet, as the brief arctic summer arrives and melts the surface snow into rushing glacial torrents, a delicate and highly specialized survivor emerges from the barren slate gravel. The Arctic Apollo ( Parnassius arcticus ) is a biological marvel—a high-altitude, glacial relict butterfly that has adapted to live closer to the North Pole than almost any other member of its order. The Physiology of a Sub-Zero Specialist To survive in a landscape dominated by permafrost and rock, Parnassius arcticus has evolved a suite of morphological adaptations that make it lo...