An invisible enemy: the battle to save black-footed ferrets from the plague

Yersinia pestis killed millions of people across Europe in the middle ages. Today it remains a deadly threat to one of the US’s most endangered speciesEvery year, from August to November, Travis Livieri becomes nocturnal. The field biologist goes out in his truck in Conata Basin, South Dakota, armed with a spotlight in search of one of the most endangered mammals in North America: the black-footed ferret. When the light catches the reflective green shine of the ferret’s eyes, he wait