Last week I told you that I find the research suggesting milk may not be good for us very unconvincing. This week we continue the conversation by asking the question When did dairying begin? If it began in the Paleolithic era, as I believe, then our genes have been depending on these nutrients for thousands of generations.
The History of Domestication
Various historical writers have tried to sell us on the idea that people were hunter-gatherers for an extended period of time and then BAM! abruptly switched to farming the minute they learned to smelt bronze and make tools that, among other things, enabled them to put their suddenly domesticated animals to work in the fields. I have to say find it unlikely that so many major cultural changes would have taken place simultaneously.
I know, you’re probably thinking Dr Cate, you’re not a historian. Who cares what you think about history? Here’s the thing: The unraveling of history’s big questions requires input from many scientific specialists and, given the fact that there are so many claims made around the health implications of eating meat and dairy products, the history of animal domestication is very much a medically relevant topic.
So back to my point. It’s hard to harness an animal to a plow. You need leatherworkers, metalsmiths, a ton of stored seeds to plant in the fields, places to store the seeds and then to store the food that grows and on and on.
Much easier than all that is shepherding. Find a dog to train, provide it with food as long as it keeps an eye on some sheep for you, and take a nap. In other words, outsource your labor to someone else. You can even skip the dog if you can’t find one and watch over the sheep yourself. Either way, shepherding represents a gradual strengthening of the human-animal interrelationship, and this is one reason that envisioning an extended period of herding and gathering as an intermediate step in the human cultural arc between hunter and farm-laborer makes for a version of history that I find more logically appealing.
In addition to the logical appeal, genetic, linguistic and other lines of evidence bolster the idea that people were not only using animals for food but also for a kind of labor well before the Bronze age. And physics offers evidence, too, since Humans benefitted from a closer relationship with animals for reasons of thermodynamics as Thom Hartmann writes in The Last Hours of Ancient Sunlight:
Something important happened around 40,000 years ago…humans discovered that ruminant (grazing animals like goats, sheep, and cows) could eat those plants that we couldn’t, and could therefore convert the daily sunlight captured by the scrub and wild plants on that “useless” land into animal flesh, which we could eat.
To recap, first the Herder-Gatherer lifestyle allowed for periods of sedentism. Then, spending a lot of time in the same place would permit people to perfect the arts of smelting metals. Only then could Bronze age technology emerge and settled cities flourish.
The alternative Paleo lifestyle: Herder-Gatherer.
Herding and gathering cultures such as the Bakhtiari of Afghanistan, recorded in the 1925 classic documentary Grass: A Nation’s Battle for Life, are neither fully nomadic nor fully sedentary. Instead, they migrate between specific locations following the seasonal rains that supply thousands of grazing animals with vast fresh pastures of rapidly growing grass–just kind grazers love best.
Unlike members of settled farming communities, who would have had relatively less access to animal foods than the hunter gatherer for a variety of reasons, herding and gathering communities would have perhaps relatively enhanced access, especially as human populations increased and, due to the success of hunter gatherers, large game populations decreased.
It is often suggested, within the Paleo movement, that wild animals are healthier than domesticated. This argument has been used to support the notion that members of hunting societies would eat animals that are more optimally nourished than animals available to members of herding societies. But this argument may not apply to truly traditional herding societies. Firstly, their human masters protect them against injury from predators and so they would be less prone to nutrient-sapping infections than their wild counterparts. And secondly, these massive human/animal encampments would scare off competition from other herbivores for the best grazing land, optimizing the domesticated grazers’ nutrition in comparison to their wild counterparts.
The number of herder-gatherer societies surviving to modern times far outweighs the number of hunter-gatherer, testifying to the success of the herding as a way of life.
Now we have another hurdle before us: Just because human were herding animals way back then doesn’t mean we were drinking their milk.
The Squirt Heard ‘Round the World
Consider this: What do you think would happen if, one moonlit night, a Nanny goat lost its calf to sickness or a predator, and was loudly expressing the pain of swollen, un-milked udders in such a way as to disturb the owners of the animal?
If we can agree that such a loud disturbance may have been enough to rouse Paleolithic parents from slumber, then what do you think a woman in this situation would have done? To calm the animal she might have done the same as she would for a sister who’d lost a baby: Encourage the expression of milk. And so, if we agree with the assertion that herding began as early as 40,000 years ago, and there is good evidence for this, then with this thought experiment we have humans milking animals possibly as early as 40,000 ago.
Of course, one thought experiment is pretty sketchy evidence. So we need to consider another line of evidence linking dairying with a Paleolithic lifestyle: The effect of dairy on adult height.
The 40,000 year old revolution.
It happens that 40,000 years ago marks another significant event in our ancestral history: The ‘extinction’ of Homo neanderthalensis.
When bones disappear from the skeletal record, we must consider two possible causes. Either the species fails to reproduce (extinction) or the skeletal structure has changed (evolution). Most archaeologists now believe that birds descended from dinosaurs, which means many species of dinosaur may never have gone extinct. Instead, they evolved into modern-day versions of their Jurassic ancestors.
I believe a similar transformation occurred in our ancestral history due to a shift in diet. This is especially likely given that, thanks to the science of epigenetics, we now know food can change genes. Here’s a simple model for how this metamorphosis may have played out: Neanderthal man changed his diet in some profound way and that altered his genes, and his anatomy. In other worlds, Neanderthal man may not represent some dead branch of the evolutionary tree, but rather a branch on the limb from which Homo sapiens blossomed.
With this in mind, let’s now consider what we know about the biological effect of milk on growth and physical appearance.
We know that, aside from containing minerals and protein that allow our bones to grow in all dimensions (thickness, width, and height), fresh and unprocessed milk contains lactoferrin, a bioactive compound that appears to stimulate bone growth in such a way as to lengthen a person’s limbs and make a person taller. (Lactoferrin promotes preferential growth of primary chondrocytes before puberty.) Lactoferrin’s action on chondrocytes offers a biological explanation for the observation that dairying tribes of Africa tend to grow taller—with long, graceful limbs—in comparison to non-dairying tribes (the most extreme example of which would be pygmies).
If milk can make people taller, and if people started drinking milk 40,000 years ago, we might expect something in the skeletal record of our ancestral past indicating a relatively abrupt increase in height. Is there?
It appears so. One of the most obvious differences between Neanderthal and early Homo sapien’s is height, with the former estimated to average five foot six, and the latter several inches taller. Much of this difference comes directly from limb lengthening. Neanderthal femurs, for example, average 19.55 inches and early Homo sapiens average 20.7.
Of course, all such archaeologic evidence is based on very small sample sizes and a hefty helping of extrapolation, so that the discovery of just two or three new skeletons may shift the evidence dramatically. Still, I think that these ideas give us a different perspective of how ancient peoples’ relationship with animals could have influenced our modern anatomy. We shouldn’t dismiss the idea of milk being Paleo simply because we’re not accustomed to the image of distant ancestors drinking milk. We didn’t used to imagine dinosaurs with feathers, or the brightly colored harlequin coat of a leftover-scavenging Tyrannosaurus rex. But that’s what makes science fun: New evidence invites us to revise the very images with which we form our worldview.
Right now, all around the world, there are people milking camel, sheep, cows, horses, goats and maybe a few more animals and this goes on in tropical, dessert, mountainous, and almost every other climate. With dairy’s current worldwide popularity, and the possibility that dairy has been directing our growth for as long as 40,000 years, then we have to consider the potential risks involved in depriving our genes of these ‘expected’ nutrients.
One of the reasons people eliminate dairy is that they can’t digest it very well. This begs the question, if dairy has been such a part of the human evolutionary narrative, why would it now give so many people tummy-troubles? That’s a good question. I addressed the lactose issue in last week’s post and will discuss other barriers to consuming dairy in the future, so stay tuned!