On Earthworms and Recipes

Published:December 1, 2015 by Brendan Wolfe


Between Columbus Day and Thanksgiving, Americans think a lot this time of year about that fateful first contact between Europeans and Native Americans. I ran across this blog post on a site dedicated to, of all things, the history of recipes, and it talks about what scholars have come to call the Columbian Exchange. Our entry on the Age of Exploration defines the term:

With Columbus and his followers arrived new people, new plants and animals, and new diseases … The exchange went both ways, of course, but for various reasons Europeans were much less vulnerable. Scholars estimate, for instance, that between 1492 and 1650, 95 percent of all the inhabitants of the Neotropic ecozone, an area covering Central and South America, died of disease. This massive depopulation resulted in significant changes in the environment and may even have led, according to at least one scientist, to a cooling of worldwide temperatures.

In other words, the Columbian Exchange, for Native Americans, was mostly a disaster, but the blog post focuses on how to teach one of the many splendid upsides: how the exchange of different foods broadened the palettes of people across the world.

All of which reminded me of another quirk of the Columbian Exchange: earthworms. According to studies reported on by Charles C. Mann in his excellent book 1493: Uncovering the New World Columbus Created (2011) these creepy crawlies that are so familiar to us did not exist in New England, the upper Midwest, and possibly in other parts of North America at the time of Columbus. Killed off by the last Ice Age, they were reintroduced probably by the English colonists at Jamestown.


When Englishmen loaded their barrels of tobacco onto ships bound for London, the ships emptied ballast from the holds to make room, and that ballast generally consisted of stones, gravel, and dirt. With English dirt came English earthworms.

So what? you might reasonably ask. Mann explains:

In temperate places like Virginia, earthworms can turn over the upper foot of soil every ten or twenty years; tiny ecological engineers, they reshape entire expanses … In worm-free woodlands, leaves pile up in drifts on the forest floor. When earthworms are introduced, they can do away with the leaf litter in a few months, packing the nutrients into the soil in the form of castings (worm excrement). As a result, according to Cindy Hale, a worm researcher at the University of Minnesota, “everything changes.” Trees and shrubs in wormless places depend on litter for food. If worms tuck nutrients into the soil, the plants can’t find them. Many species die off. The forest becomes more open and dry, losing its understory, including tree seedlings. Meanwhile, earthworms compete for food with small insects, driving down their numbers. Birds, lizards, and mammals that feed in the litter decline as well.

As the forest changed, so therefore must the people who depended on it change. Burnings, agriculture, diet: it must have been affected. Here would be an interesting essay question: How did the lowly earthworm change Virginia Indian recipes?

As for the longterm: “Nobody knows what happens next,” Mann writes. “‘Four centuries ago, we launched this gigantic, unplanned ecological experiment,” Hale told me. “We have no idea what the long-term consequences will be.'”

IMAGES: The Beauty of the Earthenware Vessels in Which They Cook Food, ca. 1590 (The Mariner’s Museum); creepy-crawlies