Milk, the Drink of Conquerors

The long, slow process of towards adult lactose tolerance started some time after the last ice age.

The drink of conquerors? Not wine, or rum, or even the blood of your enemies - but milk. Plain old milk.  

Recent scientific discoveries suggest that the spread of farming across prehistoric Europe may have gone hand in hand with the increase in lactose tolerance. This would have given the invading farmers and herders a crucial advantage over the native hunter-gatherers.

Lactose is a complex sugar occurring in milk (less in other dairy products). Like other mammals, humans in their infancy produce lactase, an enzyme that helps them digest their mother's milk. Once weaned, most mammals stop producing lactase, after which they become lactose intolerant. Symptoms, although not always severe, may include nausea, cramps, flatulence, diarrhoea and vomiting.  

Most human populations, however, have developed some degree of lactase persistence, enabling them to digest milk beyond the breast-feeding stage. It is estimated that 75% of the overall world population undergoes some decrease in lactase production, but that figure varies widely, in accordance with the genetic heritage of particular populations. Northern Europeans show only a 5% decrease in lactase production throughout their adult lives, whereas that figure is over 70% in Southern Europe. The fraction of adult lactose intolerance can be as high as 90% in some African and Asian countries. 

The long, slow process of towards adult lactose tolerance started some time after the last ice age, as humanity was switching from hunting and gathering to a somewhat less precarious subsistence on agriculture. About 10 millennia ago, Middle Eastern farmers worked out a way to decrease the lactose levels in milk by fermenting it into yoghurt or cheese. Eventually, a genetic mutation led to lactase persistence in some populations, allowing them to drink milk throughout their adult lives. This would have been a valuable evolutionary advantage over lactose-intolerant people, who would have less nutritional options when crops failed. 

This map shows the lactase hotspots of the Old World [1], with the Lands of the Milk Drinkers marked in the darkest hues. There are four core areas with a population over 90% lactose-tolerant: western Africa (in an area roughly contingent with modern Mauritania), the middle part of the Arabian peninsula, the Indus estuary (in southern Pakistan) and the north west of Europe (including the British Isles, southern Scandinavia and the coastal areas of the continent, with one deep jut into central Europe). The layer-like distribution of consecutive zones of decreasing lactose tolerance seems to indicate that the Milk Drinkers, in each of these four zones, were able to progress deep into the territories of their lacteally challenged neighbours. 

The map also points to a handful of zones where these lactase-deficient peoples reign supreme. The areas of lightest shading, indicating less than 10% of the population are lactose tolerant, are in southern Africa (most of Namibia, parts of South Africa), a small island in the east of Sudan (Darfur?), a tiny area on the Bo Hai Sea in China (not far from present-day Beijing), and a large zone in southern China, also covering most of Birma/Myanmar, all of Thailand, Laos, Cambodia and Vietnam, Malaysia (including the northern part of Borneo), and a part of Papua New Guinea.

These lightest areas too are surrounded by radiant zones, but the lactose-intolerant zones don't radiate out, but in. One clue is their location: mostly in remote, sparsely populated areas [2]. The zone in southern Africa, for example, is notable for its Khoisan population, the hunting-gathering remnant of the region's original, pre-Bantu peoples.

The ability to hold down milk is of course but one of many dietary factors that contributed to the evolutionary success of certain strains of humanity. Making the right choice as to which crops to grow, which animals to husband and which areas to explore all contributed to a tribe's multiplication - or annihilation. But this map indicates that the milk factor, isolated and mapped out, can be a meaningful tool to interpret the ebb and flow of certain human migration patterns.

Many thanks to Roi Espino Cid for sending in this map, found here on PBS. This recent piece on the PBS website deals with the milk/conquest issue, but doesn't seem to refer directly to the map.

Strange Maps #618 

Got a strange map? Let me know at


[1] I.e. Europe, Africa and Asia, the three continents (partly) known to the Ancients, interconnected and interacting before the discovery of the New World (i.e. the Americas) and Australia (although Australia too is included on this map).

[2] Beijing and the South East Asia are of course anything but sparsely populated; but we suppose this map reflects the genetic disposition of pre-modern populations, before recent waves of regional and global migration reduced the statistical relevance of 'native' populations.

The world and workforce need wisdom. Why don’t universities teach it?

Universities claim to prepare students for the world. How many actually do it?

Photo: Take A Pix Media / Getty Images
Sponsored by Charles Koch Foundation
  • Many university mission statements do not live up to their promise, writes Ben Nelson, founder of Minerva, a university designed to develop intellect over content memorization.
  • The core competencies that students need for success—critical thinking, communication, problem solving, and cross-cultural understanding, for example—should be intentionally taught, not left to chance.
  • These competencies can be summed up with one word: wisdom. True wisdom is the ability to apply one's knowledge appropriately when faced with novel situations.
Keep reading Show less

What the world will look like in the year 250,002,018

This is what the world will look like, 250 million years from now

On Pangaea Proxima, Lagos will be north of New York, and Cape Town close to Mexico City
Surprising Science

To us humans, the shape and location of oceans and continents seems fixed. But that's only because our lives are so short.

Keep reading Show less

From zero to hero in 18 years: How SpaceX became a nation-state

SpaceX's momentous Crew Dragon launch is a sign of things to come for the space industry, and humanity's future.

SpaceX founder Elon Musk celebrates after the successful launch of the SpaceX Falcon 9 rocket with the manned Crew Dragon spacecraft at the Kennedy Space Center on May 30, 2020 in Cape Canaveral, Florida. Earlier in the day NASA astronauts Bob Behnken and Doug Hurley lifted off an inaugural flight and will be the first people since the end of the Space Shuttle program in 2011 to be launched into space from the United States.

Photo:Joe Raedle/Getty Images
Politics & Current Affairs
  • SpaceX was founded in 2002 and was an industry joke for many years. Eighteen years later, it is the first private company to launch astronauts to the International Space Station.
  • Today, SpaceX's Crew Dragon launched NASA astronauts Bob Behnken and Doug Hurley to the ISS. The journey will take about 19 hours.
  • Dylan Taylor, chairman and CEO of Voyager Space Holdings, looks at SpaceX's journey from startup to a commercial space company with the operating power of a nation-state.
Keep reading Show less

Six-month-olds recognize (and like) when they’re being imitated

A new study may help us better understand how children build social cognition through caregiver interaction.

Personal Growth
  • Scientists speculate imitation helps develop social cognition in babies.
  • A new study out of Lund University shows that six-month-olds look and smile more at imitating adults.
  • Researchers hope the data will spur future studies to discover what role caregiver imitation plays in social cognition development.
  • Keep reading Show less
    Scroll down to load more…