As an undergraduate, I was fascinated by teeth. In organismal biology, teeth often tell the story: based on their shape, number, composition, and condition we can infer how an animal amassed food, how it migrated, or how it diverged from similar creatures. Teeth linger long after death, providing material traces of the distant past, but the intimate experience of holding a tooth also collapses that temporal distance, enabling us to vividly imagine the features of its former owner. Thus inspired, I wrote my thesis on what may be the world’s most astounding tooth: the long, spiralling tusk of the narwhal (Monodon monoceros). I estimated tusk breakage rates from photographs, examined specimens at museums, and read widely about this reclusive polar mammal. But to this day, I have never seen a narwhal. My knowledge of the species was constructed entirely via images, testimonials—and teeth.
The narwhal’s remarkable tusk projects up to three meters (ten feet) in front of the animal’s face, its purpose unclear. This helical structure typically erupts from the left side of a male narwhal’s jaw—though fifteen percent of females have one, and some males have two. Some studies suggest that it is a sexually selected trait, with large-tusked animals more likely to secure mates and fend off competitors. If so, the tusk may be primarily used for display, as it is likely too brittle to serve as a sparring weapon. Other researchers argue for a sensory function, pointing to the tusk’s complex system of dentinal tubules. These tiny channels may allow narwhals to detect changes in water temperature, pressure, and salinity, perhaps enabling males to locate females. Recent drone footage even suggests that the tusk may be used in capturing prey.
Such research is as urgent as it is intriguing, with the potential to inform conservation policy, as narwhals are thought to be highly vulnerable to climate change. These late-maturing creatures may be unable to adapt to rapid environmental shifts, which might bring predators or even COVID-19 to their habitats, while variations in sea ice formation can pose dangers during their annual migrations. Yet records of narwhal populations rarely extend more than a few decades into the past, making it difficult for biologists to assess the effects of these changes. Many current projects therefore involve collaborations between institutionally funded scientists and the Indigenous communities that have hunted and observed narwhals for centuries. Nonetheless, even the best of these collaborations represent only a small step toward dismantling the colonial structures of academia, which have long discredited forms of knowledge beyond the narrow bounds of Western European empirical science.
I currently study another category of discredited knowledge, though one that once predominated throughout Europe: medieval zoology. From a modern perspective, medieval texts on animals can seem untethered from reality, with their inclusion of mythical beasts alongside those we would consider mundane. Indeed, narwhal tusks often appeared in medieval treasuries, usually identified not as teeth, but as horns belonging to a terrestrial ungulate: the unicorn. A belief in unicorns may seem emblematic of the credulity and ignorance of the medieval period, but as narwhals themselves remind us, the surface rarely reveals the whole truth. In fact, the link between narwhals and unicorns sheds light on how knowledge is produced today, particularly when that knowledge is derived from stories and relics.
In medieval and early modern Europe, narwhals were everywhere and nowhere. Their tusks were valuable commodities, used to make drinking vessels, weapons, ceremonial staves, and in one astonishing case, a throne. Yet, as art historian and curator Xavier Dectot observes, most Europeans likely never saw an intact narwhal. Even the Greenland Norse, who brought these tusks to the continent, probably obtained tusks from the degraded remains of narwhals hunted by orca. Some texts describe what seem to be narwhals—notably, the thirteenth-century Konungs skuggsjá (King’s Mirror) mentions the fragility of its tusk. But these brief reports pale next to the literary and artistic traditions associated with the unicorn, a frequent subject of elaborate paintings, tapestries, and sculptures. Unicorns had great cultural importance, having long been associated with the power and humility of Christ, whereas narwhals were simply another flavor of sea monster. And so, as archaeologist Aleksander Pluskowski argues, many Europeans fitted narwhal tusks into their existing models of the world. The texts had told of unicorns, and here, at last, was evidence.
Spiralling back to the present, medieval interpretations of narwhal tusks remind us that scientific inquiry is never fully objective, nor fully separate from the artistic productions of the society in which it occurs. When we identify these structures as tusks and imagine their original functions, we inevitably do so through the lens of our own cultural heritage. Even as the solid and durable tooth lies before us, we approach it through a fluid network of ideas, particularly when our understanding of the animal relies on written accounts rather than first-person experience. If the resources available to me had emphasized unicorns instead of narwhals, I might have reacted differently to the objects that I saw in the museum, perhaps ascribing my sense of awe to the magical properties of unicorn horns. Indeed, narwhal tusks still inspire a sense of wonder that resonates with medieval descriptions of unicorns; whether we view it as horn or tooth, the tusk remains an extraordinary object for which empirical science has not yet furnished a stable explanation.
In light of the complexity of climate change, it is clear that we benefit from cultivating a plurality of knowledge practices and acknowledging the wonder that other species may inspire, which can lend momentum to conservation efforts. Like other natural materials, teeth can, in fact, tell many stories, connecting us not only with the life histories of particular animals, but also with the varied and winding histories of human societies.
 Kyle J. Lefort, Colin J. Garroway, and Steven H. Ferguson, “Killer Whale Abundance and Predicted Narwhal Consumption in the Canadian Arctic,” Global Change Biology 26, no. 8 (2020): 4276-4283; Kristin Laidre et al., “Unusual Narwhal Sea Ice Entrapments and Delayed Autumn Freeze-Up Trends,” Polar Biology 35, no. 1 (2012): 149-154.
 See e.g. Aaron Dale and Derek Armitage, “Marine Mammal Co-Management in Canada’s Arctic: Knowledge Co-Production for Learning and Adaptive Capacity,” Marine Policy 35, no. 4 (2011): 440-449. Leanne Betasamosake Simpson has published extensively on the need for such approaches to be tied to larger decolonial efforts, see e.g. “Land as Pedagogy: Nishnaabeg Intelligence and Rebellious Transformation,” Decolonization: Indigeneity, Education & Society 3, no. 3 (2014): 13-14, 21-22.
 The Greenland Norse may also have acquired tusks from Thule hunters, though direct contact between these groups may have been rare and generally hostile. See Xavier Dectot, “When Ivory Came from the Seas: On Some Traits of the Trade of Raw and Carved Sea-Mammal Ivories in the Middle Ages,” Anthropozoologica 53, no. 1 (2018): 168-170.
*Cover image: Narwhals swim beside pack ice in Baffin Bay, between Greenland and Baffin Island, Nunavut. Photo by Mads Peter Heide-Jørgensen via NOAA Photo Library.
[*Cover image description: Several narwhals cluster close together in a narrow channel with ice on both sides. One lifts a tusk above the water.]