What is killing the Tasmanian devil? A virulent cancer is infecting them by the thousands  -- and unlike most cancers, it's contagious. Researcher Elizabeth Murchison tells us how she's fighting to save the Taz, and what she's learning about all cancers from this unusual strain. Contains disturbing images of facial cancer.

Fighting a contagious cancer

Cancer can behave like an infectious disease, as seen in Tasmanian devils where a facial tumor spreads through biting, decimating over ninety percent of local populations. This cancer is unique because it is transmitted by living cancer cells, not by a virus. Genetic analysis showed that every tumor shares identical DNA, meaning the disease originated from a single individual and now passes from animal to animal. Such contagious cancers are rare but reveal surprising lessons about evolution, species vulnerability, and the persistent adaptability of cancer itself.