The Academy of Natural Sciences

search

skip to content

You are in: Home > Museum > Online > Jefferson's Fossils > Other Page > Buffon's American Degeneracy (part 3)

Buffon's American Degeneracy:
Part 3 - Modern Perspectives

The comte de Buffon's theory of American Degeneracy received spirited criticism from American writers, most notably Thomas Jefferson. They attacked it in part because it was offensive, but they also rejected it because many of Buffon's supporting "facts" were simply wrong. Indeed, Jefferson commented in his Notes on the State of Virginia that Buffon (and his anatomist Daubenton) apparently had not "measured, weighed or even seen those [animals] of America."

Buffon clearly made numerous factual mistakes in his work. In large measure, these were the result of the imperfect and incomplete data he received from distant lands; he was dependent upon whatever specimens and accounts his sources provided. Much of the information and specimens he received concerning North America came from New France (French Canada), a region characterized by a harsh climate, low animal diversity and low biological productivity (1). Most of the remaining information from other regions of the world was restricted to the coastal margins; the vast interiors of the Americas, Africa, and tropical Asia were essentially unknown.

Buffon's ideas on American Degeneracy were also a product of Eurocentrism that was understandable in the light of recent history. By the mid-18th century, Europe had experienced a remarkable ascendancy. Their forces easily overwhelmed local resistance throughout much of the world, particularly in the Americas. Their successes were in part the result of the technological, economic and military superiority, but it also resulted from the devastating impact of Eurasian diseases. It was easy to see non-Europeans as inferiors.

Although Buffon's work was hampered by limited knowledge, he clearly didn't let that stop him from generalizing and theorizing. For instance, he was correct in noting how much more frigid Quebec was than Paris even though they occupied nearly the same latitude (2). On the other hand, he made a major blunder when he concluded that the climate in the American Tropics was also remarkably cold; an error caused by a generalization from a single upland location in Peru.

Although many elements of Buffon's theory of American Degeneracy were problematic —or even ridiculous— he did present some remarkable insights. He introduced issues that later became central to the development of Evolutionary Biology.

Many of Buffon's contemporaries embraced Linnaeus' system of classification in which the taxon, usually the genus, was defined by a single or limited set of idealized features. This approach was based on the old Platonic idea of essentialism; individuals within a species (or genus) shared the same, unchanging "essence." Variability within a species was highly constrained by this "essence" and differences among species were distinct and unyielding (3). Whereas Linnaeus' disciples ignored variation within species or "solved" it by defining new species, Buffon addressed this variability head-on. He proposed a moule intérieur (interior mold) that guided the embryological development and subsequent growth of animals. Although the moule interieur was unchanging, the resulting animal could be modified by its environment (i.e., by climate, diet and/or domestication).

Buffon referred to this environmental modification as degeneration. Animals removed from their ideal environment degenerated from their ideal form. They would then pass their degenerated state onto their offspring. This could happen if an animal emigrated from its "center of origin", which would explain the geographic varieties or races commonly seen in wide-ranging species. A more drastic form of degeneration occurred via domestication. These animals would be almost always be subjected to environmental conditions far removed from those in which their first ancestors (prototypes) were created. Consequently, domesticated species exhibited even greater variety than their wild counterparts.

Buffon's concept of degeneration is now discredited, but through it he pressed the issue of intraspecific variability, something his scientific successors would have to resolve. In addition, Buffon's opposition to the Linnaean system of classification, which was based on a narrow set of "essential" anatomical features, would lead him to develop an alternative system. He considered schemes that would take into account an animal's physiology, ecology, functional anatomy (e.g., flying vs. swimming), behavior and geography. This approach ultimately proved unwieldy, but it did make him sensitive to patterns often ignored by Linnaean taxonomists. In particular, it led him to create a new science: biogeography.

Earlier naturalists either ignored the issue of geographic origins or assumed that all creation originated from one source (e.g., Noah's ark). Buffon introduced the concept of multiple "centers of origin" in the context of degeneration. He stated that animals were created in and ideally suited for particular regions. In addition, Buffon alternative classification schemes led him to grouping animals by geography; he organized animals into faunas.

The analysis of faunas led Buffon to the realization that certain faunas shared some species whereas others had little in common. In particular, North America shared many animals with Europe and Northern Asia (e.g., wolf, deer, bear and beaver). On the other hand, many of the animals found in South America (e.g., sloth, anteater, llama, armadillo and tapir) were found nowhere else (4). Similarly, many animals present in North America and Eurasia were absent from South America. An even greater surprise, however, was that the tropical animals from South America differed from those of Africa. It was clear that climate alone could not explain the composition of faunas (5).

The emergence of puzzling biogeographic patterns would undermine some traditional and biblical accounts of creation. They would also become a crucial driving force in the development of what is arguably Buffon's most significant work, Des époques de la nature (Epochs of Nature). In this masterwork, Buffon explores the roles of geography, climate, extinction and history in the shaping of Nature. (See Epochs of Nature.)

top of page

Websites:

1. Tom Gidwitz's web pages on the Great American Interchange:
   www.tomgidwitz.com/main/id80.htm

top of page

Print Resources:

1. Buffon, Georges Louis LeClerc, Comte de. 1749-1788. Histoire naturelle, générale et particulière. Paris: Imprimeries royale.
2. Gould, S.J. 2000. "Inventing Natural History in Style: Bufon's Style and Substance." pp. 75-90. In: The Lying Stones of Marrakech: Penultimate Reflections in Natural History. New York: Harmony Books.
3. Lang, I.A. 2002. Ice Age Mammals of North America: A Guide to the Big, the Hairy, and the Bizarre. Missoula: Mounain Press.
4. Mayr, E. 1982. The Growth of Biological Thought: Diversity, Evolution, and Inheritance. Cambridge & London: Harvard University Press.
5. Roger, J. 1997. Buffon: a Life in Natural History. Translated by S. Lucille. Edited by L.P. Williams. Ithaca: Cornell University Press. Originally published as Buffon, un philosophe au Jardin du Roi. 1989. Librairie Artheme Fayard.
6. Simpson, G.G. 1980. Splendid Isolation : The Curious History of South American Mammals. New Haven: Yale University Press.
7. Stehli, F. G. and S. D. Webb. 1985. The Great American Biotic Interchange. Plenum Press. New York.
   Webb, S. D. 1994. "Successful in spite of themselves and the Great American Interchange." Natural History, April, 103(4):50-53.

top of page

Notes:

1. New France (including much of present day Quebec Province) is a region with long, harsh winters, low-diversity boreal forests and heavily glaciated soils. The diversity and abundance of its mammals are relatively low and the land is not as readily cultivated as it is further south. In addition, the French colonial economy was dominated by the fur trade rather than by agricultural production. A dependence on game hunting by the colonials may have substantially depleted wildlife and selectively culled the older individuals. Specimens sent to France may have reflected a recent degradation of wildlife stocks as well as an inherently depauperate fauna. [go back]
2. The scientific understanding of climate in the mid-18th century was poorly developed. It was widely accepted that tropical regions were generally hotter because they received more direct sunlight than did regions closer to the poles. However, the contrast of the frigid climate in Quebec with the moderate climate in Paris was puzzling. It wasn't until much later that scientists realized that European climates were moderated by the Gulf Stream, a massive current that delivers water warmed in the American Subtropics to Western Europe. Ironically, an American contemporary of Buffon, Benjamin Franklin, played a significant role in our understanding of the Gulf Stream. [go back]
3. One hint of the power of essentialism in Western thought can be found in the history of the word "species." The word use to be the standard translation of Plato's Greek word for "essence." [go back]
4. The Malaysian tapir was not yet known to Europeans. [go back]
5. Buffon's insight into the uniqueness of the South American fauna would be elaborated upon by subsequent biogeographic and paleontological studies. As it turns out, South America experienced a long history of geographic isolation during which a unique fauna evolved. Large carnivores (e.g., cougar, wolf and bear) were absent. Instead, the largest predators were giant flightless "terror birds" (e.g., Titanis). Large herbivores were characterized by two major lineages unique to the Americas. One was a diverse group on ungulates (hoofed mammals) that are now extinct. Examples include the horse-like proterotheres, and rhino-sized toxodonts. Xenarthrans comprised the other great lineage. Representatives include some living forms such as tree sloths, anteaters and armadillos as well as some extinct forms such as ground sloths and glyptodonts.
   
   South America's isolation came to an end in the late Miocene (8 million years ago) when island chains permitted some limited migration between North and South America. The establishment of the Panama land bridge about 2-3 million years ago set the stage for the "Great American Interchange", one of the greatest faunal exchanges in Earth's history. North American forms —many of which originated in Eurasia— were generally more successful in colonizing South America than the South American forms in colonizing North America. This asymmetry became even more pronounced following the late Pleistocene mass extinction. Nearly half of the mammal genera that currently live in South America came from the north. Some tropical forms from South American (e.g., monkeys) successfully occupy Central America, but only three genera remain established in the temperate zone: armadillos, Virginia opossum, and porcupine. Ironically, several of the unusual species that first attracted Buffon's attention, such as the llama and the tapir, originated from either North America or the Old World. [go back]

top of page