Although he’s been dead for nearly 500 years, Leonardo da Vinci is still remembered as the quintessential Renaissance man, a polymath whose curiosity and creativity ranged widely among the arts and sciences. One of his interests was the study of fossils. In a new paper in the journal Palaios, Andrea Baucon shows that he was a pioneer in the study of both “body fossils,” or the remains of once-living organisms, and of “trace fossils,” such as the footprints, burrows and coprolites organisms left behind.
During da Vinci's lifetime, most people saw fossils not as the remains of creatures that had lived long ago, but as the products of forces inside the earth that were trying to reproduce life within rock, constantly generating the stone "shells" and dark "shark teeth" found many miles from the nearest ocean. But da Vinci thought differently: as Baucon points out, his private notes in the Codex Leicester show that he had figured out that the fossils of the Italian countryside had once been creatures that lived in an ancient sea. His insights into the origin and nature of body fossils anticipated what the naturalist Nicolaus Steno would explain in the mid-17th century.
What’s more, Baucon provides new evidence that da Vinci also pioneered ichnology, or the study of trace fossils, which historians of science usually see as beginning in the early 19th century, with the work of naturalists such as like William Buckland and Edward Hitchcock. That evidence is in da Vinci’s Codex Leicester, a journal he compiled between 1504 and 1510.
Among the fossils da Vinci investigated were mollusk shells and corals, many of which showed signs that living organism had bored into them, much as "woodworms" (actually beetle larvae) chewed their way through trees. Da Vinci appealed directly to the woodworm model in refuting the idea that fossils were "sports of nature" produced by forces within the earth. Why, he asked, would these forces produce such borings on a shell? Furthermore, he noticed signs of movement between different layers in which the fossils (what we call “bioturbation” today), which he interpreted as further support for the idea that the fossil beds contained the remains of prehistoric animals. For da Vinci, there was only one reasonable explanation: the body fossils had been entombed among signals of their own activity.
Historians and scientists have recognized da Vinci's unpublished insights for many years, but he was apparently even more astute than previously appreciated. He used what he knew about living organisms to confirm the organic nature of the fossils. (Although, it should be noted, other naturalists saw similar phenomena and attributed them to the “plastic force” inside the earth. It would be a few centuries before da Vinci's view would be independently redeveloped by Steno, Robert Hooke, and others.) One might wonder how the science of paleontology might have been different had da Vinci published his conclusions—he initially intended to, but like many of his projects it eventually fell by the wayside. Even so, the notes he left behind show that he was far ahead of his peers. As Baucon concludes:
In these early days of ichnology, Leonardo da Vinci stands out as the central figure, reaching conclusions that were extraordinarily innovative, and linking the study of trace fossils to the study of body fossils. These conclusions were extremely important, as da Vinci was able to understand the relationships of trace fossils and body fossils and interpret them accurately prior to the development of the scientific method.
BAUCON, A. (2010). LEONARDO DA VINCI, THE FOUNDING FATHER OF ICHNOLOGY PALAIOS, 25 (6), 361-367 DOI: 10.2110/palo.2009.p09-049r