In the second half of the 1700s, French natural historian Georges-Louis Leclerc, Comte de Buffon, formulated what would be dubbed the “New World degeneracy” or the “American degeneracy” theory. His work, Histoire Naturelle, Générale et Particulière, included a vast array of facts about natural history from around the world as well as the Count’s many ideas about the history of the Earth and the organisms that inhabit it. According to Buffon, a set number of distinct types of life generated near a central point. He suggested that species then underwent change as they migrated, affected by their new environments. In a way, Buffon was proposing a sort of proto-evolutionary hypothesis nearly one hundred years before Darwin.
The Count argued that all animals in the New World were degenerate compared to those in the Old World. “Animated nature, therefore is less active, less varied, and even less vigorous,” Buffon wrote, “for by the enumeration of the American animals we shall perceive, that not only the number of species is smaller, but that in general, they are inferior in size to those of the old continent.”
Buffon had never been to North America, and instead based his claims on specimens in the French King’s Cabinet of Natural History, prior published material on North America, accounts from travelers who had been to the New World, and a small menagerie he kept at his summer home, which included some New World and Old World animals.
Cold and humid environments, Buffon maintained, led life to degenerate. The land mass of the New World, Buffon believed, had been under water for a much longer period than the Old World. Therefore, North America was a relatively new continent that had not had time to heat up or dry out. The result was a cold continent with an extraordinarily humid land and stagnant swamps everywhere. According to the Count, only insects and reptiles could flourish in such an environment. Consequently, humans—whom the Count thought had migrated to the continent via a land bridge that once connected Eurasia with North America—and domesticated animals brought to America were doomed to be smaller and feebler.
American Indians, Buffon affirmed, were responsible for the increase in humidity and the rate of degeneration, as they had failed to drain the swamps: “In these melancholy regions Nature remains concealed under her old garments, and never exhibits herself in fresh attire; being neither cherished nor cultivated by man, she never opens her fruitful and beneficent womb.”  For the Count, American Indians were:
A kind of weak automaton, incapable of improving or seconding her [Nature’s] intentions. She treated them rather like a stepmother than a parent, by refusing them the invigorating sentiment of love, and the strong desire of multiplying their species. For, though the American savage be nearly of the same stature with men in polished societies; yet this is not a sufficient exception to the general contraction of animated Nature throughout the whole Continent. In the savage, the organs of generation are small and feeble. He has no hair, no beard, no ardour for the female . . . He has no vivacity, no activity of mind . . . He remains in stupid repose, on his limbs or couch, for whole days . . . They have been refused the most precious spark of Nature’s fire: They have no ardour for women, and, of course, no love to mankind . . . Their love to parents and children is extremely weak. The bonds of the most intimate of all societies, that of the same family, are feeble; and one family has no attachment to another . . . Their heart is frozen, their society cold, and their empire cruel. They regard their females as servants destined to labour, or as beasts of burden, whom they load unmercifully with the produce of their hunting, and oblige, without pity or gratitude, to perform labours which often exceed their strength. They have few children, and pay little attention to them. They are indifferent, because they are weak.
Histoire Naturelle was well received in Europe, where Corneille de Pauw’s Récherches philosophiques sur les Americains, published in 1768, and Guillaume-Thomas François Raynal’s Histoire philosophique et politique, published in 1770, extended Buffon’s ideas to Creoles—Europeans born in America. According to de Pauw, degeneracy had and would continue to affect Europeans emigrating to North America and their descendants:
The Europeans who pass into America degenerate, as do the animals: a proof that the climate is unfavorable to the improvement of either man or animal. The Creoles, descended from Europeans and born in America . . . have never produced a single book. This degradation of humanity must be imputed to the vitiated qualities of the air stagnated in their immense forests, and corrupted by noxious vapours from standing waters and uncultivated ground.
When these ideas reached the shores of North America, the backlash was swift. Both James Madison and Alexander Hamilton expressed their disapproval, but it was Jefferson who came up with an effective rebuttal.
The French government had instructed the secretary of the French legation in Philadelphia, François Barbé-Marbois, to gather as much information as possible on the former thirteen British colonies. Barbé-Marbois prepared a list of twenty-two queries to be distributed to the governors of each state. The questionnaire, through Joseph Jones, Virginia delegate to the Continental Congress in late 1780, got to Thomas Jefferson, the then governor of Virginia. Jefferson’s response, Notes on the State of Virginia, was an overview of his home state. The longest chapter, titled “Productions mineral, vegetable, and animal,” precisely confuted the New World degeneracy theory.
Before delving into Jefferson’s answer, it is necessary to understand what prompted him to answer in the first place. First off, Jefferson did not deny that climate could affect the size of animals. Instead, he maintained that climate, even when it affected the size of animals, worked within defined limits. In particular, he believed animals to have a maximum and a minimum size, both set by their “Maker.” “What intermediate station they [animals] shall take,” Jefferson wrote, “may depend on soil, on climate, on food, on a careful choice of breeders. But all the manna of heaven would never raise the mouse to the bulk of the mammoth.”
Furthermore, Jefferson pointed out that there was no evidence that differences existed in the climates of the two worlds that would lead to life in the New World being degenerate:
The opinion of a writer [Buffon], the most learned too of all others in the science of animal history, [is] that nature is less active, less energetic on one side of the globe than she is on the other. As if both sides were not warmed by the same genial sun; as if a soil of the same chemical composition, was less capable of elaboration into animal nutriment; as if the fruits and grains from that soil and sun, yielded a less rich chyle, gave less extension to the solids and fluids of the body, or produced sooner in the cartilages, membranes, and fibres, that rigidity which restrains all further extension, and terminates animal growth. The truth is, that a Pigmy and a Patagonian, a Mouse and a Mammoth, derive their dimensions from the same nutritive juices.
As Benjamin Franklin presented Jefferson with data that showed that London and Paris were more humid than Philadelphia, the Virginian convinced himself even more that additional studies and facts were needed to draw an accurate conclusion:
As to the theory of Monsr. de Buffon that heat is friendly and moisture adverse to the production of large animals, I am lately furnished with a fact by Doctr. Franklin which proves the air of London and of Paris to be more humid than that of Philadelphia, and so creates a suspicion that the opinion of the superior humidity of America may perhaps have been too hastily adopted. And supposing that fact admitted, I think the physical reasonings urged to shew that in a moist country animals must be small, and that in a hot one they must be large, are not built on the basis of experiment. These questions however cannot be decided ultimately at this day. More facts must be collected, and more time flow off, before the world will be ripe for decision. In the mean time doubt is wisdom.
Another factor that made Jefferson question the Count’s theory was the reliability of some of the sources—Frenchmen who had traveled to the New World. Specifically, he asked whether those people were reliable and trustworthy like Buffon and his colleagues working in the king’s garden, whether they had natural history as the “object of their travels,” and whether they measured or weighed “the animals they speak of.” “A true answer to these questions,” he concluded, “would probably lighten their authority, so as to render it insufficient for the foundation of an hypothesis.”
Overall, regarding the validity of the theory, Jefferson wrote:
I am induced to suspect, there has been more eloquence than sound reasoning displayed in support of this theory; that it is one of those cases where the judgment has been seduced by a glowing pen: and whilst I render every tribute of honor and esteem to the celebrated zoologist [Buffon], who has added, and is still adding, so many precious things to the treasures of science, I must doubt whether in this instance he has not cherished error also, by lending her for a moment his vivid imagination and bewitching language.
Last but not least, a practical rather than a theoretical question made it imperative to push back against the accusation of degeneracy coming from the Old World. Jefferson was aware that a prosperous future for America would depend heavily on economic relations with other countries and, above all, on a continuous influx of immigrants from Europe. Buffon’s theory, which argued that the climate of the New World made life degenerate, cast a bad light on the nascent republic.
Whether claims of American degeneracy were made in Europe with the intention of targeting and hurting American affairs—supposedly with the goal of preventing America’s economic and geographic expansion—this is impossible to establish with certainty. What is certain is that the idea that subjects could easily obtain vast tracts of land overseas was not very appealing to European monarchs.
Jefferson began his response by defining the fundamental points of Buffon’s thought and by summarizing his reasons:
The opinion advanced by the Count de Buffon, is 1. That the animals common both to the old and new world, are smaller in the latter. 2. That those peculiar to the new, are on a smaller scale. 3. That those which have been domesticated in both, have degenerated in America: and 4. That on the whole it exhibits fewer species. And the reason he thinks is, that the heats of America are less; that more waters are spread over its surface by nature, and fewer of these drained off by the hand of man. In other words, that heat is friendly, and moisture, adverse to the production and development of large quadrupeds.
To counter the Count’s claims, he used tables to compare the size of a small sample of animals found in both the New and the Old World (table 1), the size of animals found only in the New World with those found only in the Old World (table 2), and the size of animals domesticated in both (table 3). Jefferson’s conclusions were as follows:
The weights actually known and stated in the third table preceding will suffice to shew, that we may conclude, on probable grounds, that, with equal food and care, the climate of America will preserve the races of domestic animals as large as the European stock from which they are derived; and consequently that the third member of Mons. de Buffon’s assertion, that the domestic animals are subject to degeneration from the climate of America, is as probably wrong as the first [the animals found in both continents are smaller in America] and second [the animals peculiar to the New World are on a smaller scale] were certainly so.
That the last part of it is erroneous, which affirms that the species of American quadrupeds are comparatively few, is evident from the tables taken altogether. By these it appears that there are an hundred species aboriginal of America. Mons. de Buffon supposes about double that number existing on the whole earth.
As for Buffon’s evidence of the degeneracy of American Indians, nothing Jefferson read in European writings struck him as accurate. Not familiar with the Indigenous peoples of South America, his defense mainly concerned the Indians of North America, of whom Jefferson said he could speak based on his own knowledge and “the information of others better acquainted with him, and on whose truth and judgment” he could rely:
From these sources I am able to say, in contradiction to this [Buffon’s] representation, that he [the Indian] is neither more defective in ardor, nor more impotent with his female, than the white reduced to the same diet and exercise: that he is brave, when an enterprise depends on bravery; education with him making the point of honor consist in the destruction of an enemy by stratagem, and in the preservation of his own person free from injury; or perhaps this is nature; while it is education which teaches us to honor force more than finesse: that he will defend himself against an host of enemies, always chusing to be killed, rather than to surrender, though it be to the whites, who he knows will treat him well: that in other situations also he meets death with more deliberation, and endures tortures with a firmness unknown almost to religious enthusiasm with us: that he is affectionate to his children, careful of them, and indulgent in the extreme: that his affections comprehend his other connections, weakening, as with us, from circle to circle, as they recede from the center: that his friendships are strong and faithful to the uttermost extremity.
To provide his readers with an example that disproved the idea of Indian degeneracy, Jefferson resorted to an eloquent speech by Logan, an Iroquois leader whose family was murdered in retaliation by a group of Virginia militia. The militia’s punitive expedition, caused by the robbery and murder of a frontiersman in the spring of 1774 by two Shawnees, ruined the good relations that had been established between the tribes and the settlers, leading to Lord Dunmore’s War. When the Shawnee lost a decisive battle, peace negotiations began. Logan “disdained to be seen among the suppliants. But, lest the sincerity of a treaty should be distrusted, from which so distinguished a chief absented himself,” he sent by a messenger a speech that was later reproduced and very much admired in Europe:
I appeal to any white man to say, if ever he entered Logan’s cabin hungry, and he gave him not meat; if ever he came cold and naked, and he clothed him not. During the course of the last long and bloody war, Logan remained idle in his cabin, an advocate for peace. Such was my love for the whites, that my countrymen pointed as they passed, and said, ‘Logan in the friend of white men.’ I had even thought to have lived with you, but for the injuries of one man. Col. Cresap, the last spring, in cold blood, and unprovoked, murdered all the relations of Logan, not sparing even my women and children. There runs not a drop of my blood in the veins of any living creature. This called on me for revenge. I have sought it: I have killed many: I have fully glutted my vengeance. For my country, I rejoice at the beams of peace. But do not harbour a thought that mine is the joy of fear. Logan never felt fear. He will not turn on his heel to save his life. Who is there to mourn for Logan?—Not one. 
Buffon, in describing the American Indians, acknowledged that they were about the same stature as Europeans, but argued that they were unable to reason, feel, and love. This, according to the French naturalist, was the cause behind their less developed civilizations. According to Jefferson, this added to the long list of things that did not make sense:
But if cold and moisture be the agents of nature for diminishing the races of animals, how comes she all at once to suspend their operation as to the physical man of the new world, whom the Count acknowledges to be ‘à peu près de mème stature que l’homme de notre monde’ [about the same stature as the man in our world], and to let loose their influence on his moral faculties? How has this ‘combination of the elements and other physical causes, so contrary to the enlargement of animal nature in this new world, these obstacles to the developement and formation of great germs,’ been arrested and suspended, so as to permit the human body to acquire its just dimensions, and by what inconceivable process has their action been directed on his mind alone?
In other words, Jefferson wondered how it was possible for nature to affect animals and humans in such different ways. In the absence of facts, the American concluded that “to form a just estimate of their [the Indians’] genius and mental powers, more facts are wanting, and great allowance to be made for those circumstances of their situation which call for a display of particular talents only. This done, we shall probably find that they are formed in mind as well as in body, on the same module with the ‘Homo sapiens Europæus.’“
To the accusation that America had not produced any brilliant mind, Jefferson argued that the country was relatively young and needed time to cultivate great poets. Rome and France, he said, needed time to produce a Virgil and a Voltaire, consequently the same time had to be given to America.
Population, Jefferson pointed out, was an important factor as well:
Of the geniuses which adorn the present age, America contributes its full share. For comparing it with those countries, where genius is most cultivated, where are the most excellent models for art, and scaffoldings for the attainment of science, as France and England for instance, we calculate thus. The United States contain three millions of inhabitants; France twenty millions; and the British islands ten. We produce a Washington, a Franklin, a Rittenhouse [David Rittenhouse, Philadelphia astronomer, instrument craftsman and patriot]. France then should have half a dozen in each of these lines, and Great-Britain half that number, equally eminent.
Jefferson completed Notes in 1781, initially sharing it with Marbois and just a few other colleagues. Soon, others learned about the work and asked for copies. Hence, in 1784, while serving as a member of the Continental Congress in Philadelphia, Jefferson discussed Notes with a local publisher, but was dissatisfied with the time it would take to print the copies and the price it would cost him. As a result, he took the manuscript with him to Europe that same year, when the Confederation Congress appointed him as Minister Plenipotentiary to France, directing him to join Benjamin Franklin and John Adams in Paris.
Here Jefferson had the first copies of Notes printed in English by a Parisian printer in 1785. He then discreetly distributed these among a small circle of friends and acquaintances in France (one copy was transmitted to Buffon, whom Jefferson had yet not met) and America. The decision to keep the distribution of Notes under his control was due to Jefferson’s concern for the outrage that his liberal ideas (particularly that of the separation of church and state in a new Virginia Constitution and his anti-slavery stance) would have caused in his home state.
Jefferson’s statements of belief in political, legal, and constitutional principles, such as individual freedoms, checks and balances, and constitutional government, were what preoccupied him:
I had 200 copies printed, but do not put them out of my own hands, except two or three copies here, and two which I shall send to America, to yourself and Colo. Monroe, if they can be ready this evening as promised . . . I beg you to peruse it carefully because I ask your advice on it and ask nobody’s else. I wish to put it into the hands of the young men at the college, as well on account of the political as physical parts. But there are sentiments on some subjects which I apprehend might be displeasing to the country perhaps to the assembly or to some who lead it. I do not wish to be exposed to their censure, nor do I know how far their influence, if exerted, might effect a misapplication of law to such a publication were it made. Communicate it then in confidence to those whose judgments and information you would pay respect to: and if you think it will give no offence I will send a copy to each of the students of W.M.C. and some others to my friends and to your disposal. Otherwise I shall only send over a very few copies to particular friends in confidence and burn the rest. Answer me soon and without reserve. Do not view me as an author, and attached to what he has written. I am neither. They were at first intended only for Marbois. When I had enlarged them, I thought first of giving copies to three or four friends. I have since supposed they might set our young students into a useful train of thought and in no event do I propose to admit them to go to the public at large.
Despite Jefferson’s precautions, a certain Monsieur Barrios managed to obtain a copy of the book and planned to translate it into French without permission. To avoid this, Jefferson worked on a French edition with the help of Abbé Morellet, a member of the Académie française. This edition, however, did not please Jefferson at all. The Virginian was forced to publish an English edition in order to prevent the public from thinking that the French version, which often changed the meaning of the original, was accurate.
Therefore, in 1787, the book’s first public edition, issued in London, began to be sold, while a year later, an American edition was published in Philadelphia. By the turn of the century, Notes was used as a popular handbook for natural history and geography and reprinted in newspapers all over the United States.The battle with Buffon, however, was not over. Jefferson was not satisfied; he wanted more—he wanted to change the Count’s mind.
Sometime in late 1785, Jefferson, while dining with Buffon, realized that the Count had mischaracterized the American moose for a reindeer. Buffon, open to confrontation, told Jefferson that if he could present him with proof that the American moose was indeed as imposing as the Virginian claimed, he would correct his mistake. It is impossible to know whether the Count intended to retract his theory of degeneration. It is very likely, however, that Jefferson left the dinner meeting convinced of this.
At this point in the story, Jefferson’s task was to bring an American moose to France. To do this, he enlisted the help of John Sullivan. Sullivan, a prominent New Hampshire figure, despite countless difficulties, managed to get Jefferson the carcass of a moose. Jefferson thanked him and wrote that he hoped that “Buffon will be able to have him [the moose] stuffed and placed on his legs in the king’s cabinet.” Unfortunately, the Count died shortly after receiving the carcass. There was no retraction and the New World degeneracy theory outlived both Buffon and Jefferson.
The two engaged in a scientific debate in a field that was relatively unexplored at the time, yet their contribution to natural history was remarkable, as Histoire Naturelle, Générale et Particulière and Notes on the State of Virginia continued to influence generations of naturalists and philosophers decades later. The American degeneracy theory finally vanished in the 1850s, when the death of its key players and advancements in science rendered it obsolete.
Dugatkin, Lee A. Mr. Jefferson and the Giant Moose: Natural History in Early America. Chicago: University of Chicago Press, 2009.
Georges-Louis Leclerc de Buffon, Historie Naturelle, Générale et Particulière, vol. 9, Quadrupèdes VI (Paris: Imprimerie Royale, 1761),87, gallica.bnf.fr/ark:/12148/bpt6k1067248h/f11.item.
Cornelis de Pauw, A General History of the Americans, of Their Customs, Manners, and Colours (Rochdale: T. Wood, 1806), 17-18, archive.org/details/generalhistoryof00pauwarch/page/n3/mode/2up.
Guillaume-Thomas François Raynal, Histoire Philosophique et Politique, vol. 6 (Amsterdam, 1770), 376, gallica.bnf.fr/ark:/12148/bpt6k109692c.texteImage.
James Madison to Thomas Jefferson, June 19, 1786, founders.archives.gov/documents/Madison/01-09-02-0017; Alexander Hamilton, “Federalist No. 11:The Utility of the Union in Respect to Commercial Relations and a Navy,” The Independent Journal, November 24, 1787, avalon.law.yale.edu/18th_century/fed11.asp.
Thomas Jefferson, Notes on the State of Virginia(Philadelphia: Prichard and Hall, 1788), 45, docsouth.unc.edu/southlit/jefferson/jefferson.html.
Jefferson to Chastellux, June 7, 1785, founders.archives.gov/documents/Jefferson/01-08-02-0145.
Edward D. Seeber, Modern Language Notes, vol.61, no. 6 (Johns Hopkins University Press, 1946), 415, doi.org/10.2307/2908929.
Jefferson to James Madison, May 11, 1785, founders.archives.gov/documents/Jefferson/01-08-02-0094.
Jefferson to John Sullivan, October 5, 1787, founders.archives.gov/documents/Jefferson/01-12-02-0208.