How a 6,000-Year-Old Dog Cancer Spread Around the World
High in the Himalayas, a heavy-coated dog trots behind the hem of a Buddhist monk’s robes. On the streets of Panama City, another dog collapses into a sliver of shade, escaping the heat of the midday sun. On their bodies a cancer grows. Their tumors each appear unique—their swollen, crumbling contours flush with fresh blood vessels emerging from beneath a tail here or between the legs there. But the cells dividing inside each one, continents apart, are actually the same organism. If you can call a clump of 6,000-year-old cancer cells an organism.