The anatomy of a monster
The legend of the Tarasque of Tarascon, recorded as early as the 12th century, describes a very specific beast. It was said to have a lion's head, an ox-like body protected by a turtle's shell, six legs with bear claws, and a scaly tail ending in a scorpion's sting. This dragon, supposedly the offspring of the biblical Leviathan and a mythical Onachus, terrorized the Rhône riverbank. It hid in the river, sinking boats and devouring the local population, until Saint Martha arrived in Provence around 48 AD. The story, popularized by Jacobus de Voragine's "The Golden Legend," recounts how Martha found the beast, pacified it with hymns and holy water, and led it back to the village. The terrified villagers promptly killed the subdued creature. In their remorse, and after Martha preached a sermon, they renamed their town from Nerluc to Tarascon.
A dragon in the strata
This mythological anatomy may have a basis in the region's geology. The area around Tarascon contains many marine sediments from the Miocene epoch, which lasted from 23 to 5.3 million years ago. Erosion from the Rhône river regularly exposes fossils from these deposits. Medieval villagers, without any context for paleontology, would have encountered the strange and enormous bones of extinct creatures. Two prime candidates exist for the Tarasque's inspiration. The first is the Miocene sea cow, Metaxytherium. These large marine mammals, ancestors of the dugong, are common fossils in the region. An eroded, disarticulated skeleton of a Metaxytherium could present a confusing picture: a large, barrel-shaped rib cage might be interpreted as a turtle's shell, and its heavy, unusually shaped skull could resemble a lion's head to an unfamiliar eye.
The second candidate is an extinct species of large crocodile. Fossilized crocodilian remains, including jaw fragments and the bony plates called osteoderms that form their skin armor, are also found in the Miocene and older Cretaceous deposits of Provence. The discovery of a large, toothy reptilian skull, combined with a jumble of heavy vertebrae and armored scutes, explains a dragon legend. The combination of fossils from several different large animals—a sea cow's torso, a crocodile's head and armor, and perhaps the leg bones of a large land mammal—could easily have been reconstructed into the chimera-like Tarasque.