First off, don’t be fooled by the title: A Plague of Frogs: The Horrifying True Story would be more aptly, but less apocalyptically, entitled A Plague on Frogs: The Disconcerting True Story. I eagerly dove into William Souder’s real-life scientific adventure/mystery with neo-Biblical visions of amphibians raining upon good Lutherans in rural Minnesota dancing in my head. Rather, this book is not about what frogs have done to us, but what we most likely, tragically, have done to them.
Souder, a journalist from Grant, Minnesota, who first reported on this story for The Washington Post, has given us a balanced, thoughtful, well-written and compelling report of a recent outbreak of extravagant deformities among frogs and other amphibians along the northern tier of the United States and southern Canada, with Minnesota as its apparent epicenter – an outbreak that may or may not have dire implications for human health.
The human concerns stem from the fact that many scientists view frogs as “sentinel species,” environmental canaries-in-a-coal-mine that act as early warning alarms for the system at large, and for vertebrates – including humans – in particular. Frogs are in recession throughout the world and this is alarming because frogs have been exceptionally successful animals, existing largely unchanged for 350 million years.
Yes, their habitat is being crowded by human development, but simple encroachment does not explain their precipitous decline over the last 30 years, with many species being reduced by as much as 80%, and an across-the-board reduction in the size of individual animals. Frogs are particularly susceptible to environmental insult because they are literally permeable. As Souder puts it, “A frog’s skin is less a barrier against the outside world than it is an open portal.”
Plague is peopled with a large cast of flummoxed scientists, baffled bureaucrats, and bemused bystanders who are too often a name and a very brief introductory description: the teacher who first reports the deformities, Cindy Reinitz, is simply a “tall, attractive woman with long red hair and a purposeful stride” (there is much purposeful striding over glade and glen in these pages). Amid the burgeoning cast and the acronyms – MPCA (Minnesota Pollution Control Agency), NIEHS (National Institute of Environmental Health Sciences), DAPTF (Declining Amphibian Populations Task Force – picture a swat team of herpetologists), and the EPA, among many others – my brain was periodically aswim like Donald in Mathemagic Land.
Nonetheless, several characters emerge three-dimensional and heroic, including the forbearing Bock family, upon whose seemingly idyllic land destiny placed the most afflicted pond, with deformity rates eventually reaching 100%; the dogged herpetologist David Hoppe, whose hands-on field experience gave credence to the view that something new and nasty had beset Minnesota frogs in the summer of 1995; the systematic, sensitive young French-Canadian Martin Ouellet, a former-veterinarian who single-handedly established an ironclad link between deformed frogs (missing legs, multiple legs, withered legs, malformed jaws, skin webbing, etc. ad nauseum) and agricultural chemicals by collecting and observing over 40,000 specimens in rural Ontario; the poetic neuroanatomist and U.S. coordinator of the DAPTF, Mike Lannoo; and Alan Pounds, the American biologist who solved the mystery of the disappearance of the golden toad from the Monteverde cloud forest of Costa Rica, the most famous extinction of modern times. The unraveling of that mystery at the end of the book elegantly ties together the book’s main threads for Souder, a conclusion I will not reveal.
The structure of the book is essentially a chronological investigation of the deformity outbreak from the various perspectives of the large cast, with special attention to the scientists who proffered competing theories for the outbreak, which drew national media attention and increased in severity every summer as each new cohort of tadpoles metamorphosed into frogs from ’95 until the book’s conclusion in late ’99.
The four main proposed causes for the achingly misshapen frogs – none of which have ever lived to maturity – were chemical, parasitic, predatorial, and ultraviolet radiation. The mechanisms by which these agents could cause the deformities, especially the extra and missing limbs, is explained carefully by Souder, usually in the form of interviews with the various proponents. He does a good job of making highly technical anatomic, developmental and cellular issues clear to the lay reader.
Souder also makes it clear that science is as political and fad-driven as any other human endeavor, and that scientists can be as stubborn, petty, and territorial as their fellow homo sapiens. Yet in the end, every character has a point to make and at least a moment of nobility. Ultimately there are no obvious villains in the plague upon our froggy friends, and that is what’s most frightening of all.