Why Do We Eat Some Animals But Not Others?

The Question Itself

In most US households, a dog is a family member, a pig is dinner, and a cow is somewhere in between depending on the context. The categories feel obvious from inside the culture. They are not obvious from outside it. Different cultures draw the lines in different places: cows are sacred across most of India, dogs are food in some Korean traditions, horses are routine cuisine in France, insects are a staple in much of Southeast Asia and have been missing entirely from most Western menus.

That the lines vary is not, by itself, an argument against having lines. Every culture sorts the natural world; the question is why these particular lines, in this particular culture, and whether the reasons hold up to scrutiny. The page below is a tour of the evidence and the major ethical positions. The reader does the concluding; the page tries not to.

Cross-Cultural Variability

Hal Herzog, an anthrozoologist at Western Carolina University, opens his 2010 book Some We Love, Some We Hate, Some We Eat by cataloging the patterns. The same species occupies radically different roles across cultures and across time within the same culture: rabbits as pets, lab animals, and meat in the same Western markets, often within the same week of an individual consumer’s purchases. Horses, eaten in France and Belgium and rarely in the English-speaking world. Cows, the most consumed large mammal globally and the most protected in much of South Asia. Insects, a major protein source in much of the world and largely off Western tables until very recent start-up-driven attempts to change that.

The anthropological literature on these patterns is substantial. The lines tend to track specific factors: what was domesticable in the local ecology; what religious traditions codified into law; what colonial trade networks moved which species across; what carried social status versus stigma in a given period. Margo DeMello’s Animals and Society is a standard survey textbook for the cross-cultural literature.

What the survey does not produce is a clean explanation. Some lines map cleanly to ecological availability — you don’t eat what you don’t have. Some map to religious traditions that long outlasted the conditions that produced them. Some are recent enough to track to specific commercial and cultural developments within living memory. The categories are real, and they are also contingent.

The Psychological Mechanisms

The psychologist Melanie Joy coined the term carnism in her 2010 book Why We Love Dogs, Eat Pigs, and Wear Cows. Her framing names what she argues is an invisible belief system: that some animals are food and others are not, and that the categories are received as natural rather than chosen. Joy’s analytic move is to make a default visible by giving it a name; the carnism framework is widely cited in the food-ethics literature and contested within it. Critics argue the framework collapses several distinct cognitive moves into one term; defenders argue that the unified naming is precisely what allows the defaults to be examined. Both critiques have force.

Below the framework, the underlying cognitive research is the longer-standing literature on cognitive dissonance: the discomfort that arises when behavior and belief do not align, and the strategies people use to reduce that discomfort. Applied to food, this looks like what researchers have called the “meat paradox” — the gap between caring about animals in some contexts and eating them in others. The research on this gap is consistent enough across studies to be considered well-documented: most omnivores in most cultures report caring about animal welfare and also continuing to eat animals, and the cognitive moves that bridge the two have been characterized in detail.

The bridging moves are not bad-faith. They are ordinary cognition under ordinary circumstances. The most common are: dissociation (decoupling the animal from the food product), denial (believing the animals are well-treated regardless of evidence), and dichotomization (categorizing some species as food-types and others as pet-types so the same moral considerations don’t apply to both). The research describes the moves; it does not, by itself, tell anyone whether the moves are defensible.

Historical Contingency

The historian Richard Bulliet’s book Hunters, Herders, and Hamburgers walks through how species got sorted, over millennia, into work animals, food animals, and companion animals — and how the sorting froze around specific species in ways that look like natural law from inside but were a sequence of accidents from outside. Cattle and pigs were domesticated as work-and-food species in Eurasia; dogs as work-and-companion; cats as commensal-and-pest-control; horses as work-and-prestige. The categories carry weight because they were repeated for thousands of years; they are not, however, biologically determined.

Jared Diamond’s Guns, Germs, and Steel covers a related question: which species were domesticable at all, and why some continents had more candidates than others. The book has been productively contested in academic geography and anthropology for some of its broader claims; the chapter on domestication candidates is the durable contribution. Whatever you make of Diamond’s thesis on civilizational divergence, the underlying point about why pigs and cattle and not, say, zebras and hippos became standard food animals is well-documented and substantially ecological.

The historical point bears on the ethical question because it removes one common move: the argument that the food-animal categories reflect what those animals “are for.” The categories reflect what specific humans, in specific places, with specific ecological constraints, did with the animals available to them several thousand years ago. The persistence of the categories is real; the necessity of them is harder to defend.

The Contemporary Ethics

Several major positions in contemporary ethics give defensible answers to the question of what humans owe non-human animals. They are presented below without ranking among them. Each has serious philosophical defenders, internal debates, and lines of disagreement with the others.

Utilitarianism (consequentialist)

Peter Singer’s 1975 book Animal Liberation made the modern utilitarian case. The argument is that the morally relevant property is the capacity for suffering, that suffering counts equally regardless of the species experiencing it, and that practices producing large amounts of avoidable suffering are difficult to justify on utilitarian grounds. Critics argue the utilitarian framework cannot account well for relational obligations, for the moral significance of personhood versus mere sentience, or for the practical limits of welfare comparisons across species. Defenders argue that the simplicity of the framework is its strength.

Deontology (rights-based)

Christine Korsgaard’s Fellow Creatures (2018) is a contemporary deontological case for animal ethics rooted in Kantian thought. The argument is that non-human animals are ends in themselves, not merely means; that obligations to them follow from the same rational structure that produces obligations among humans; and that treating sentient beings as resources is categorically (not just consequentially) problematic. The Tom Regan tradition makes a related rights-based case from a different philosophical starting point. Critics argue the rights framework over-extends concepts designed for rational agents; defenders argue this objection underestimates what Kantian thought can accommodate.

Virtue ethics

The virtue-ethics tradition, with roots in Aristotle and modern development in writers including Rosalind Hursthouse, asks what a virtuous person does. Applied to animals, the question becomes one about the kind of character formed by participating in different relations with non-human animals — the cultivation of compassion, practical wisdom, justice — rather than about rules or outcomes directly. Different virtue-ethics writers reach different conclusions about specific practices; the framework is less concerned with universal verdicts than with the formation of moral character over time.

Care ethics and relational frameworks

Lori Gruen’s Ethics and Animals and the broader care-ethics tradition emphasize that moral reasoning happens inside concrete relationships, not against abstract principles in isolation. Mary Midgley’s Animals and Why They Matter (1983) is a foundational text in this register; her framing of humans as one species among many that share a moral landscape has influenced subsequent care-ethics work. Care-ethics conclusions tend to be specific to specific relationships rather than universal.

Cultural pluralism

A separate position, less often theorized but commonly held in practice, is that food categories are properly part of cultural inheritance, that there is no view from nowhere from which to assess them, and that critiques of specific food practices from outside the culture are themselves a kind of cultural overreach. This position has serious defenders and is part of the live discussion; it is not, in the academic literature, a marginal view. Critics argue it can be used to bracket questions that deserve scrutiny; defenders argue that cross-cultural moral imposition has its own track record worth attending to.

A Frame for Thinking About Your Own Consistency

A reader who has stayed with the page this far does not need Steampunk Farms to provide a verdict. What may be useful is a frame for the work of thinking it through. Three questions, none meant rhetorically, all meant for the reader to answer themselves over time:

• Where do the lines fall in my current practice — which species do I treat as food, which as companions, which as something else — and what reasons would I give if asked?
• Do the reasons hold up across species, or do they apply differently to different categories in ways I have not examined?
• If the reasons do not hold up symmetrically, am I comfortable with the asymmetry, and if so, why?

The questions are not designed to push toward any particular answer. They are designed to make the existing answer explicit, whatever it is. The companion pillar on Are Pigs Intelligent? covers the cognitive-capacity evidence that often enters this kind of reflection. The companion pillar on What Is Factory Farming? covers the system that most US food-animal categories now sit inside. None of those pages picks a conclusion; this one will not either.