Overview of 71. Why Is Pig Milk the One Milk We Don’t Drink? (No Stupid Questions — Freakonomics Radio)
Hosts Stephen Dubner and Angela Duckworth respond to a listener who asks why humans drink so many kinds of mammal milk (cow, goat, camel, yak, reindeer, horse, etc.) but barely ever pig milk. The episode traces the history and biology of dairy consumption, practical and behavioral barriers to milking pigs, rare exceptions, related ethical/religious questions, and a lighter conversation about “disgusting” foods worth trying (offal, fermented foods, insects). A final fact-check corrects and expands several claims from the conversation.
Key takeaways
- Drinking animal milk is a relatively recent human habit (post‑Neolithic, ~10,000 years) tied to pastoralism and domestication.
- Most commonly consumed milks come from ruminants (cows, goats, sheep, buffalo, reindeer, yak) whose biology and temperament make milking practical.
- Pigs are numerous (~670 million globally) and female pigs produce milk, but practical, behavioral, and taste factors make pig milk rarely used commercially.
- Main practical barriers: sows are hard to milk (aggressive, skittish), their mammary anatomy/behavior resists regular extraction, and pig milk’s properties (watery, gamey) complicate cheese-making.
- Rare/novel examples exist (a Netherlands farm produced pig‑milk cheese sold at charity auction for very high prices), but production is extremely limited and not scalable.
- Religious/medical use of pig parts (e.g., heart valves, xenotransplants) raises questions about permissibility; many faiths permit lifesaving measures (pikuach nefesh in Judaism).
- The hosts also discuss foods many people find gross but are worth trying (anchovy paste, gefilte fish, durian, natto, fried/candied insects, offal).
Why pig milk isn’t commonly consumed
Biological & behavioral reasons
- Sows are not as docile or cooperative as dairy cows. Pigs are described as “smart, skittish, suspicious, and paranoid,” and lactating sows can become aggressive—making routine milking dangerous or impractical.
- Mammary anatomy/behavior and pig nursing patterns make mechanized or hand milking difficult compared to ruminants.
Milk composition and culinary suitability
- Reports describe pig milk as comparatively watery and “gamey.” Those qualities reduce its appeal for drinking and complicate cheese production.
- Cheese-makers value milk with fat and casein properties conducive to coagulation; many ruminant milks are better suited.
Economic and logistical factors
- Even where pigs are abundant, they’re primarily raised for meat. Dairy requires different husbandry, infrastructure and incentives.
- Plant‑based milks and established dairy industries already supply consumer needs, reducing the market incentive to develop pig‑milk systems.
Notable exceptions
- A Dutch family farm (“Piggy’s Palace”) made a pig‑milk cheese block (2015) that sold at auction for charity — described as chalky and somewhat salty. Price reported up to $2,300/kg at auction (novelty/charity value).
- Chef Edward Lee and others have experimented with pig milk cheese but cited the difficulty of routine milking and handling.
Context: dairy history, global patterns, and legal notes
- Regular consumption of non-human milk began with early farmers/pastoralists; it’s not a universal human constant.
- Lactase persistence (ability to digest lactose into adulthood) varies widely by population; dietary habits and exposure influence tolerance.
- Per-capita milk consumption ranking mentioned: U.S. is mid/low (approx. 67th globally in the hosts’ citation), while high-consumption countries include Costa Rica, Bosnia & Herzegovina, Finland, Sri Lanka.
- Raw (unpasteurized) milk: legality in the U.S. varies by state—retail sale is fully legal in some states and restricted in others (fact-check detail: retail sale legal in 13 states; limited sale in 17 others).
- Comparison to marijuana legality: both have patchwork legal statuses across U.S. states (recreational marijuana fully legal in 18 states, decriminalized in others).
Pigs in medicine and religion
- Pigs have provided materials for medical use (e.g., heart valves) and are investigated for xenotransplantation (organs).
- Religious concerns (e.g., Judaism, Islam) about pig-derived medical treatments: many authorities permit use of pig parts when lifesaving (Jewish law’s pikuach nefesh principle).
“Gross” foods discussed (what to try, and why)
- Anchovy paste (host recommendation): potent umami; small amounts improve dressings and sauces—good “starter” for people wary of whole anchovies.
- Traditional Jewish/Ashkenazic items: gefilte fish, chopped liver, herring, beef tongue—familiar culturally, offal-based or chopped fish preparations.
- Fermented and pungent foods: natto (fermented soy), durian (strong smell, polarizing taste).
- Offal/organ meats: chicken hearts, turkey testicles, intestines (chinchulines), brain—listener-suggested items; often texturally challenging.
- Insects/arachnids: candied crickets, grasshoppers, tarantula—some listeners and hosts report pleasant experiences when well-prepared (candied or with cheese/salsa).
Notable quotes & moments
- Chef Edward Lee (as cited): pig’s milk “would make an incredible cheese” but “it’s nearly impossible to milk pigs” because of sow behavior.
- Hosts’ playful estimate exchange: Stephen guesses pig population analytically; Angela’s “one pig per person” quip points to the surprising real-world number (~670 million pigs).
Fact-check highlights (from the episode’s fact-check segment)
- Reindeer (caribou) are real and found across Arctic regions (Greenland, Scandinavia, Russia, Alaska, Canada).
- The U.S. recognizes 195 countries (193 UN members + Holy See + Kosovo); broader counts (200+) depend on definitions and recognition.
- Ruminant = animal with a four‑chambered stomach, typically two‑toed feet (not the same as “to ruminate” meaning to brood).
- Grey’s Anatomy was renewed through Season 18 (as of 2021).
- Raw milk and marijuana legalities vary widely across U.S. states (see specifics above).
- Casu marzu (Sardinian maggot cheese) involves live maggots digesting the cheese; locals sometimes eat it with live maggots, while others process the maggots into the product; it’s banned from commercial sale but consumed traditionally.
Practical suggestions / action items
- Curious about unusual foods? Start small and integrate potent flavors (e.g., anchovy paste in a dressing) before trying whole or texturally challenging items.
- If you’re intrigued by food history or dairy diversity, read the BBC and Slate pieces mentioned (authors cited in the episode) and look into regional dairy traditions (mare’s milk/kumis, camel milk, reindeer/elk uses).
- If considering raw‑milk purchases or pig‑derived medical options, check current local laws and medical/religious guidance.
Sources & references mentioned on the show
- BBC piece by Michael Marshall (history of milk consumption).
- Slate article by Benjamin Phelan (why we don’t drink pig milk).
- Village Voice / New York food writing (pig milk commentary).
- Chef Edward Lee (attempts/remarks on pig milk).
- Dutch “Piggy’s Palace” pig‑milk cheese (2015 auction; charity sale).
- Episode fact-check segment for legal and biological clarifications.
If you want, I can produce a one‑page quick reference (bullet list) of the practical reasons pig milk hasn’t become a dairy staple for sharing with someone who asked “Why not pig milk?”