A black-footed ferret is seen in a temporary trap prior to being vaccinated against sylvatic plague, a disease that periodically decimates populations of the highly endangered mammals, at a ferret reintroduction site on the Fort Belknap Indian Reservation, …A black-footed ferret is seen in a temporary trap prior to being vaccinated against sylvatic plague, a disease that periodically decimates populations of the highly endangered mammals, at a ferret reintroduction site on the Fort Belknap Indian Reservation, …