The Vegan Mythbusting series uses science to debunk propaganda against veganism.

As a vegan, I’ve often heard the refrain that animals are killed when plant food is harvested – effectively, animal consumers indicate that vegans eat food whose production involves wholesale slaughter of small wildlife that lives on farms. And, as they argue, since harvesting grain kills a lot of rats, fawns and nestlings, and slaughtering a cow kills only one animal, vegans are responsible for more animal cruelty than meat eaters are.

This, of course, is easy to refute, because most of the world’s grain is fed to livestock, which means that the process of producing meat kills more mice, birds and insects, plus one cow or pig or chicken. But then meat eaters argue that they consume only “grass-fed beef” – cows raised on pastures, not fed on grain. “Grass-fed” beef is all the rage now. The fact of the matter is that the “grass-fed” label is nothing more than a vague, feel-good word for scamming consumers – right up there with “farm-fresh”, “pure”, “humane” and other make-believe nonsense. I’d love to talk about how “grass-fed” cows are actually raised (hint: it’s not all that different from “grain-fed” cows), and the impact this has on our environment. But that’s something for another time.

In this little post, I'd like to have a chat with you about harvesting deaths. Is it true that producing grain kills lots of wildlife? And how much is “lots”? A few million? Thousands? Dozens? And where does this silly myth come from anyway?

In terms of marketing tactics, the meat industry today is not all that different from the tobacco industry was in the 1950’s. One of their Standard Operating Procedures is to commission ‘scientific’ studies that paint a favorable picture of their industry, or to dig up independent studies that even vaguely support their business. They then use their financial resources to use media and advertising to promote them widely. Repeat a lie a few hundred times and it becomes a valid point of view. Repeat it a million times and you’ll have yourself an irrefutable fact.

In 2003, a guy named Steven Davis, who’s an animal science professor at the Oregon State University, published a paper about the number of animals killed in producing crops, versus beef production. He didn’t actually go out into the field and measure anything, oh no, no, no! He reviewed older, existing field studies, then performed some calculations using that data. To be specific, he used studies about the drop in the numbers of mice and other animals before and after a harvest. He then proceeded to declare that producing grain causes the deaths of lots and lots of critters, eating a diet of “large herbivores” (I think he meant cows, not rhinos) kills fewer animals than cultivating crops [Davis, 2003]. Predictably, the meat industry gobbled up that study faster than actors in their TV commercials hog down bacon strips. And they promoted it wherever they could, as often as they could. Soon, media as diverse as Time, NYT Magazine and Australian Broadcasting Corporation were writing about it. Why, they asked, is the life of a cow more important than the life of a harvest mouse?

Well, scientists being scientists, decided to examine these claims more keenly. And ............ they found that the research is correct. There are a lot fewer wild animals on farms after a harvest, than before. Ouch!

But wait a minute – how do we know that all those mice and voles and birds are dead? What if they are not? Did the scientists who did this research – the very same data that Davis used to announce that beef involves less cruelty than bread – try to find out what happened to those animals? The answer is, yes, they did. Let’s have a round of applause for them.

For one, Davis used a 1993 study by Tew and Macdonald. In 1992, T & M had a fun time fitting tiny little radio collars to cute little, furry, brown, wood mice, whom they called Apodemus Sylvaticus, because that’s their sciencey name. Not one or two, but 33 of them. That almost makes me want to quit my boring desk job and become a public-funded field researcher – now where’s that shady back-alley shop that prints college diplomas?

T & M then set those 33 mice free to munch on grain, scurry, groom their fur, build nests, or whatever. All through the harvesting season, they tracked their rodent gang. Guess how many died in a grain harvester? One. One out of 33 – that’s 3.3%. In other words, 96.67% of the mice on a harvested farm were not killed by cruel bladed machines. But 17 – that’s almost 50% - were killed by other critters – owls and weasels, to be more specific. Their radio collars were found on carcasses, or chewed up in burrows, or as fancy new toys for owlets. Statistically speaking, harvesting machines had virtually no impact at all.

It’s interesting that Davis used this study and counted 18 dead mice, but didn’t care to factor in that 17 had died of predation. The devil – the Vegan Devil (RAWR!) - is in the details.

But why didn’t harvester machines kill those mice? Common sense tells you and me that since mice have ears and eyes and whiskers, when they see a huge, loud machine heading their way, they bolt for their lives - a prudent and successful strategy. Mice have perfected the art of escaping faster and stealthier things than harvester machines. Sure, baby mice in nests, or the old and infirm can’t do much, but most mice are quite adept at avoiding large, noisy things. However, since science does not place much stock in “common sense”, a team of six scientists in Argentina did research, just to be doubly sure [Cavia et al., 2005]. They measured the density of rodents on farms in central Argentina, as well as in forested areas around those farms, before and after harvests. They found that while the density of wildlife on farms was lower after the harvest, the numbers of animals in the forests had gone up significantly. That meant that when grain was harvested and their cover vanished, the animals abandoned the farms and moved to the shelter of forested areas close by.

Does the Davis study need more refuting? Why not. Davis made another mistake in his calculations. He assumed that producing food for meat eaters and vegans uses the same area of land. In fact, raising animals requires vastly more land and water than cultivating plants does. On average, meat production uses 16 times more land than producing vegan food of equivalent nutrition. There goes the math.

But all this arguing over harvester machines overlooks an important fact: most of the world’s food production does not even use machines. You see, most of the world’s farmers live in the developing world. They farm small areas of land, which makes mechanized farming cost-prohibitive. Most of the world’s farmers plow their fields with water buffalo in Vietnam, oxen in India and donkeys in Kenya. Seeds are sown with rudimentary tools, pesticides are sprayed by hand pumps and irrigation channels are dug using picks and shovels. They use this produce to feed their families and sell the surplus at local farmer’s markets. Let me put it another way: most of the plant food eaten by humans is farmed without using machines – no tractors for plowing, no aircraft for spraying chemicals, and no grain harvesters.

Crops raised for feeding meat animals, on the other hand …

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