For fifteen centuries, the indigenous peoples of the Canary Islands lived in a state of profound isolation, their survival dictated by the jagged peaks and arid plains of a fragmented volcanic archipelago. While the world beyond the horizon shifted through empires and eras, the people of these islands adapted to a singular, unchanging reality: the specific geography of the land beneath their feet.
A new study published in Scientific Reports reveals that the aboriginal diet of the Canary Islands was shaped far more by the biogeography of individual islands than by the sweeping shifts of global climate. By analyzing the chemical signatures left in human remains, researchers have reconstructed a dietary map that spans from the first century to the 15th century, illustrating a remarkable long-term adaptation to ecological niches.
The research, conducted by a team from the University of Las Palmas de Gran Canaria (ULPGC) and the University of Burgos, examined 457 human remains recovered from sites across seven islands. Using stable isotope analysis of carbon and nitrogen, the scientists were able to treat these remains as a biological archive, uncovering exactly what sustained these populations for over a millennium.
The Chemistry of Survival
To understand the prehistoric diet, the researchers looked at stable isotopes—variants of chemical elements that do not decay over time. Carbon isotopes, specifically, allow scientists to distinguish between different types of vegetation. Populations on the more fertile islands showed values characteristic of C3 plants, such as barley and wheat, which are typical of Mediterranean climates.
Nitrogen isotopes, serve as a marker for the position of a food source within the food chain. Higher nitrogen levels typically indicate a heavy reliance on marine proteins. This chemical fingerprinting revealed a stark divide between the high, mountainous islands and the low, desert-like islands of the east.
The five western and central islands—El Hierro, La Palma, La Gomera, Tenerife, and Gran Canaria—benefit from altitudes exceeding 1,500 meters. These heights trap moisture from the trade winds, creating fertile soils and diverse vegetation zones. Here, agriculture was a cornerstone of survival, with crops contributing between 30% and 50% of the total diet, supplemented by the grazing of goats, and sheep.
A Divide Defined by Geography
In contrast, the eastern islands of Lanzarote and Fuerteventura presented a different struggle. With maximum altitudes below 800 meters and a climate heavily influenced by the proximity of the Sahara Desert—located just 100 kilometers from the coast—agriculture was severely limited.
The isotopic data for these populations show significantly less negative carbon values and higher nitrogen levels. This indicates a dietary regime where the ocean was not just a supplement, but a necessity. Fish and shellfish filled the caloric void left by the arid terrestrial landscape.
Even among islands with similar climates, subtle geographical differences created distinct dietary habits. El Hierro, despite being a western island, showed a much higher consumption of marine resources than its neighbors, La Palma or La Gomera. Researchers attribute this to El Hierro’s smaller amount of arable land, which forced the population to rely more heavily on the shoreline, specifically harvesting lapas (limpets) and burgaos (modest sea snails).
Similarly, the study found that inhabitants of Gran Canaria had slightly higher nitrogen levels than those in Tenerife. What we have is linked to the presence of permanent coastal settlements in Gran Canaria, which provided the population with more consistent and easier access to the sea.
| Island Group | Primary Food Sources | Key Environmental Driver | Dietary Signature |
|---|---|---|---|
| Central/Western (e.g., Tenerife, La Palma) | Barley, wheat, goats, sheep | High altitude, trade wind rain | C3 plant dominance |
| Eastern (Lanzarote, Fuerteventura) | Fish, shellfish, limited crops | Desert climate, low altitude | High marine nitrogen |
| El Hierro | Limpets, sea snails, marine life | Limited arable land | High marine reliance |
Resilience Against a Changing Climate
One of the most surprising findings of the study is the stability of these diets over 1,500 years. The archipelago endured significant climatic fluctuations, including the Roman Warm Period, the Medieval Climate Anomaly, and the Little Ice Age. In many other parts of the world, such shifts would have forced radical changes in food production and consumption.
However, the isotopic signatures in the Canary Islands remained remarkably consistent. The “biogeographic footprint”—the difference between a Mediterranean island and a desert island—remained the dominant factor in the inhabitants’ diet, outweighing the impact of temporal climate change.
«Los isótopos estables funcionan como un archivo biológico de la alimentación. Lo que hemos descubierto es que ese archivo refleja fielmente la biogeografía del archipiélago: las islas con más recursos vegetales y agrícolas muestran una señal isotópica distinta a las islas más áridas, donde el mar era imprescindible para la supervivencia», said Elías Sánchez-Cañadillas, the study’s lead author from ULPGC.
This consistency suggests that the indigenous populations had reached a peak of adaptation to their specific environments, creating sustainable dietary systems that could withstand centuries of climatic volatility.
Jonathan Santana, a professor of Prehistory at ULPGC, noted that the findings make the archipelago an exceptional case study for human adaptation. He explained that the factor explaining the isotopic differences was not time, but geography, with each island printing its own ecological signature on its people for fifteen centuries.
Disclaimer: This article is for informational purposes and is based on archaeological and isotopic research regarding prehistoric diets; it does not constitute nutritional or medical advice.
The research team continues to analyze the relationship between these dietary patterns and the overall health and longevity of the prehispánico populations. Further updates on the isotopic mapping of the archipelago are expected as more remains are analyzed from previously unexplored sites.
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