Refugium is a technical term for a biological refuge, a place where occupants are secure from a range of threats, often lethal. Sailors in a storm seek the refuge of a harbor, a child the refuge of his mother, the patriot refuge from tyrannical government. While refugium carries all of these connotations, it primarily designates a landscape where animals and plants pursue lives protected from exploitation and pursuit. Some important refugia pass virtually unnoticed: undisturbed land along railroad rights of way and the unmanicured reaches of country cemeteries have long provided rare and endangered plants with a refuge from real estate development, agriculture, and invasions of exotic plants. Similarly, highly secured military compounds, such as the vast Marine Corps base at Twenty-Nine Palms, California, provide unintentional refuge for native ﬂora and fauna. While the United States’ national system of wildlife refuges formalizes the commonsense effort to protect the biodiversity of the country’s native ﬂora and fauna, it is in this realm of the unintended, the hidden, the inadvertent pocket of protection, that species large and small often ﬁnd their lives least disturbed. One of the most confounding questions in modern ﬁeld biology concerns the whereabouts of animals once they are lost to our senses. To put the question another way, when animals long absent from a region suddenly turn up, where, precisely, is the “somewhere” from which they came? The myths and folklore of traditional people the world over are replete with descriptions and even geographic designations of refugia, the inviolable strongholds of animals and plants of which the storyteller and her people steer clear, places very like Western society’s Eden, missing only the human, and holding out the promise of a less tumultuous future.