From dragon tongues to lunar debris: the many lives of shark teeth
In short: Long before scientists identified them as biological remains, shark teeth were believed to be petrified dragon tongues or stones fallen from the sky. Today, these calcium phosphate relics serve as a vital evolutionary archive, revealing the predatory secrets of species that vanished millions of years ago.
For centuries, the origin of triangular fossil teeth was shrouded in myth. Pliny the Elder once posited that these objects descended from the heavens during lunar eclipses. During the Renaissance, they were known as 'glossopetrae' or 'tongue stones,' widely believed to be the fossilized tongues of snakes and dragons. In Malta, they were even linked to the legend of Saint Paul, thought to be the remains of the apostle's tongue. It was not until the late 17th century that naturalists like Nicolaus Steno demonstrated their true organic origin, proving they were part of a shark's anatomy.
Beyond myth, shark teeth are remarkable biological machines. Sharks possess a continuous tooth replacement system, where new teeth form underneath and push older ones out. This turnover rate is highly dynamic: while some species can replace teeth weekly, the speed is influenced by environment, such as warmer water accelerating the process in nurse sharks. The morphology of a tooth is a direct reflection of its diet. For instance, the great white shark possesses serrated, triangular upper teeth for cutting large prey, whereas the blue shark utilizes needle-like teeth to grip slippery fish.
Because they are composed of resistant calcium phosphate, teeth are often the only part of a shark to fossilize, providing a window into the Elasmobranchii lineage dating back hundreds of millions of years. These fossils allow researchers to track evolutionary transitions, such as the shift from the extinct giant mako, Isurus hastalis, to the modern great white. Collectors also prize the massive teeth of the extinct Otodus megalodon, which lived between 28 and 1.5 million years ago. These specimens are highly valuable, with larger teeth sometimes fetching as much as 3,000 dollars.
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- Summary by Intellect · source: Shark tooth
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