Southern Siberia, RussiaThe snow leopard scented the herd of Siberian ibex on the strong wind blasting over the ridgeline at more than 11,000 feet, high in the Altai Mountains of southern Siberia, on Russia’s remote border with Mongolia, China, and Kazakhstan. With its gray coat and black spots, the big cat was nearly invisible against the rock of this arid landscape. It padded confidently toward its quarry through deep snow on wide, insulated feet, watchfully moving down an eroded draw above the frozen Chaganburgazy River.

Just above the light blue ice of the river, the cat stopped. This was a favorite spot. In the hot months, a spring ran here, feeding the braided waters of the river and attracting game. But its