by Mary Harrsch © 2025
To explore the different challenges to the development of agriculture in the Americas, I asked, “Why, then if megafauna disappeared earlier in the ancient Americas was there such a delay in the development of agriculture there as compared to Eurasia?”
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| Carved ornaments depicting the Maya maize god, Hun Huapu, 5th-7th century CE Shell Courtesy of The Metropolitan Museum of Art in New York City. |
1. Differences in Domesticated Plant and Animal Availability
• In Eurasia, many large, herd-based mammals (e.g., cattle, sheep, goats, pigs) survived and were domesticated. These animals provided meat, milk, wool, fertilizer, and labor for plowing, accelerating agricultural development.
• In contrast, after the extinction of American megafauna (~13,000–10,000 BCE), few large mammals remained for domestication. The llama and alpaca in the Andes were exceptions, but they were not widespread across the continent and were primarily used for transport rather than farming.
2. Differences in Wild Plant Availability and Suitability for Domestication
• The Fertile Crescent in Eurasia had a high concentration of wild grasses (e.g., wheat, barley, rye) that were high in protein, easily stored, and naturally productive, making them prime candidates for domestication.
• In the Americas, staple crops like maize (corn), squash, and beans required significant genetic modification before they became productive for farming. For example, early maize (teosinte) had tiny, hard kernels and took thousands of years to be selectively bred into the large, edible corn we recognize today.
There were wild cereal grains in both North America and South America, but they were not as immediately suited for domestication as the wheat, barley, and rye of Eurasia. Several factors limited their early agricultural potential compared to the wild cereals of the
Fertile Crescent:
Wild Grains of North and South America
North America:
o Eastern North America had little barley (Hordeum pusillum) and maygrass (Phalaris caroliniana), but these were not as calorie-dense or easily cultivated as Old World cereals.
o Goosefoot (Chenopodium berlandieri) and sumpweed (Iva annua) were used for food, but their yields were low compared to wheat or rice.
o Wild rice (Zizania spp.) in the Great Lakes region was widely gathered but was never domesticated in the way that rice was in Asia.
South America:
o The grasslands of Argentina, Uruguay, and Brazil (the Pampas and Cerrado regions) had wild grasses, but they were not domesticated on a large scale.
o The most important cereal from South America was maize (Zea mays), but it originally evolved from a tropical grass (teosinte) in Mesoamerica and had to be selectively bred over thousands of years.
o The Andean region developed quinoa (Chenopodium quinoa), but it’s more of a pseudo-cereal than a true grain.
Why Didn’t North & South American Grasses Domesticate Like Eurasian Grains?
• Lower Yield & Small Seeds:
Many American wild grasses had small seeds with lower caloric value than Old World cereals, making them less efficient food sources.
• Non-Shattering vs. Shattering Grains:
o In the Fertile Crescent, wild wheat and barley had natural mutations that made them non-shattering (meaning they retained their seeds rather than dispersing them easily).
o In contrast, many North and South American wild grasses retained shattering traits, making early domestication difficult.
• Less Favorable Ecology for Grain Cultivation:
o The grasslands of North America (Great Plains) were rich in bison and other game, meaning hunting was a better food source than early grain farming.
o The Pampas in South America also had abundant large game, reducing the incentive to invest in agriculture early on.
The Domestication Timeline Was Much Slower
• In Eurasia, wheat and barley were domesticated within a few thousand years after the Ice Age ended (~10,000–9,000 BCE).
• In the Americas, maize was domesticated much more slowly (from ~9,000 BCE to ~5,000 BCE), meaning fully productive grain-based agriculture emerged later.
The Americas had wild cereal grains, but they were less productive, less naturally suited to domestication, and competed with rich game and other food sources. This, combined with geographic barriers and different ecological conditions, delayed the rise of large-scale agriculture compared to Eurasia.
Geographical and Environmental Challenges
• Eurasia's east-west axis allowed crops and domesticated animals to spread easily across similar latitudes, where climates were relatively stable.
• The Americas, by contrast, have a north-south axis, meaning that crops had to adapt to major climate variations as they spread. For example, a plant domesticated in Mexico had to adapt to drastically different conditions in the Andes or North America, slowing the agricultural transition.
Continued Reliance on Hunting, Gathering, and Fishing
• After the megafaunal extinctions, American hunter-gatherers adapted to new food sources like deer, rabbits, fish, and shellfish. The abundance of wild foods in some regions may have delayed the incentive to intensively cultivate crops.
• Coastal and river-based societies (e.g., those in California, the Pacific Northwest, and the Amazon) had rich ecosystems that sustained large populations without the immediate need for farming.
Gradual Transition Rather than a Sharp Break
• In Eurasia, agriculture emerged relatively rapidly (~10,000 BCE) as people shifted from wild grain collection to farming within a few thousand years.
• In the Americas, there was a long period of experimentation before full-scale agriculture developed. Maize, for example, was first cultivated around 7000 BCE but didn’t become a staple crop until 2000–1500 BCE.
Conclusion
The earlier loss of megafauna in the Americas did not lead directly to agriculture because:
• Fewer domesticable animals remained, meaning no draft animals to plow fields.
• Suitable wild plants took much longer to domesticate.
• Geographic and climatic barriers slowed crop diffusion.
• Abundant wild resources delayed the pressure to fully transition to farming.
Ultimately, agriculture did develop independently in the Americas—just on a different timeline and under different conditions than in Eurasia.
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