Tamed
Contents
About the Book
About the Author
Praise for Tamed
Also by Alice Roberts
Title Page
Dedication
Introduction
1. Dogs
2. Wheat
3. Cattle
4. Maize
5. Potatoes
6. Chickens
7. Rice
8. Horses
9. Apples
10. Humans
Acknowledgements
References
Index
Copyright
About the Book
The extraordinary story of the species that became our allies.
Dogs became our companions
Wheat fed a booming population
Cattle gave us meat and milk
Maize fuelled the growth of empires
Potatoes brought us feast and famine
Chickens led us to wonder about tomorrow
Rice promised us a golden future
Horses gave us strength and speed
Apples travelled with us
HUMANS TAMED THEM ALL
For hundreds of thousands of years, our ancestors depended on wild plants and animals to stay alive – until they began to tame them.
Combining archaeology and cutting-edge genetics, Tamed tells the story of the greatest revolution in human history and reveals the fascinating origins of ten crucial domesticated species; and how they, in turn, transformed us. In a world creaking under the strain of human activity, Alice Roberts urges us to look again at our relationship with the natural world – and our huge influence upon it.
About the Author
Alice Roberts is an anthropologist, writer and broadcaster, and is currently Professor of Public Engagement in Science at the University of Birmingham. She has presented several landmark BBC series including The Incredible Human Journey, Origins of Us, Coast and The Celts. Her latest book on evolutionary biology, The Incredible Unlikeliness of Being, was shortlisted for the Wellcome Book Prize in 2015.
Praise for Tamed
‘Lyrical storytelling untangles the current thinking on how we’ve entwined our lives with those of plants and animals. From dogs to apples to potatoes to chickens, Roberts provides fascinating insights into domestication, offering anecdotes from past and present that link genetic and archaeological findings.’
BBC Wildlife Magazine, Book of the Month
‘Superb: fascinating, intimate biographies of the species that have shared our white-knuckle ride to the present and have helped to make us what we are. Read if you want to know what and why you are.’
Charles Foster, author of Being a Beast
‘Roberts remains composed, engaging and undogmatic throughout … Tamed is an excellent point of entry for anyone who wants to understand the new deep human history.’
Peter Forbes, Guardian
ALSO BY ALICE ROBERTS
Don’t Die Young: An Anatomist’s Guide to Your Organs and Your Health
The Incredible Human Journey
The Complete Human Body
Evolution: The Human Story
The Incredible Unlikeliness of Being: Evolution and the Making of Us
The Celts: Search for a Civilisation
To Phoebe and Wilf, who love the wild places
Introduction
‘HEAR and attend and listen; for this befell and behappened and became and was, O my Best Beloved, when the Tame animals were wild. The Dog was wild, and the Horse was wild, and the Cow was wild … and they walked in the Wet Wild Woods by their wild lones …’
Rudyard Kipling, ‘The Cat That Walked By Himself’
For hundreds of thousands of years our ancestors existed in a world where they depended on wild plants and animals. They were huntergatherers – consummate survival experts, but taking the world as they found it.
Then the Neolithic Revolution happened – at different times, and in different ways, in different places – but across the globe, those hunter-gatherers were changing how they interacted with other species in a crucial fashion. They tamed those wild species – and became herders and farmers. The domestication of plants and animals would pave the way for the modern world – allowing the human population to boom, and the first civilisations to grow up.
By uncovering this deep history of familiar species, we’ll discover just how important those plants and animals were – and are – to the survival and success of our own species. These others have teamed up with us, and are now found right around the world, and have changed our lives immeasurably. We’ll dig back in time to trace their – sometimes surprising – origins. But we’ll also find out how becoming part of our world changed those plants and animals, as we tamed them.
The origins of domesticated species
When the Victorian scientist Charles Darwin set about writing On the Origin of Species – the foundation stone of evolutionary biology today – he knew he was about to drop a bombshell – and not just into the world of biology. He understood that he had to prepare some serious groundwork before he leapt into explaining his extraordinary insight into how species changed over time, through the unthinking action of natural selection, working its magic, generation by generation. He needed to bring his readers along with him. They’d be climbing a mountain together; it would be fraught with difficulty, but the view from the top would be stupendous.
And so Darwin refrained from jumping straight into explaining his revelation. Instead, he devoted an entire chapter – a whole twenty-seven pages in my edition – to describing examples of species evolving under the influence of humans. Within a population of plants or animals, there is variation – and it’s by interacting with that variation that farmers and breeders are able to modify breeds and species, generation by generation. Over hundreds and thousands of years of humans promoting the survival and reproduction of some variants, and limiting the success of others, our ancestors had wrought change in domesticated species and strains, moulding them until they more neatly fulfilled human needs, desires and tastes. Darwin called the effect of human choice on those domesticated species ‘artificial selection’. It was an idea that he knew his readers would be familiar and comfortable with. He could describe how selection by farmers and breeders – picking out particular individuals to breed from, discarding others – would, over generations, produce small changes, and that these changes would accumulate over time so that sometimes diverse strains or subtypes would emerge – from a single, ancestral stock.
In fact, this gentle introduction to the power of selection to wreak biological change wasn’t just a literary device. Darwin had set out to study domestication himself, because he believed that it could cast light on the mechanism of evolution more generally – on how wild plants and animals could become gradually modified. He wrote, ‘… it seemed to me probable that a careful study of domesticated animals and cultivated plants would offer the best chance of making out this obscure problem. Nor,’ he added, almost with a glint in his eye, ‘have I been disappointed.’
After discussing the effects of artificial selection, Darwin could then go on to introduce his key concept of natural selection as the mechanism behind the evolution of life on the planet, the unthinking process that would, over time, propagate modifications and grind out – not just new strains – but entirely new species.
Reading his book today, the word ‘artificial’ trips us up. Firstly there’s the other meaning of ‘artificial’ – where it’s synonymous with ‘fake’. That wasn’t the sense in which Darwin was applying the word; he meant artificial as in ‘by artifice’. But even then, there’s a knowingness implied by this word which overplays the role of conscious intent in the process of domestication of species. Modern plant and animal breeding ma
y be carried out with careful, deliberate aims in mind, but the earlier history of our liaisons with the species that have become our major allies reveals a shocking lack of any planning.
So we could try to come up with a new word for ‘artificial’, but there’s another problem. Given that we now accept the fundamental role of natural selection in evolution, given that Mr Darwin doesn’t need to persuade the majority of us of this biological reality – do we actually need a separate description for the way that humans have affected the evolution of domesticated species?
Describing artificial and natural selection separately helped Darwin to build his argument, and to introduce a challenging, new idea, but the distinction is actually false. It doesn’t really matter that it’s us humans – rather than the physical environment or other species – that are mediating the assortment of individuals into those more or less likely to successfully reproduce. You wouldn’t make this distinction for any other species. Take the selective pressure exerted by honeybees on flowers – which leads to changes in those flowers over time, making them more attractive to their pollinators. The colours, shapes and scents of flowers are not designed to delight our senses – they have evolved to entice in their winged allies. Have the honeybees been effecting artificial selection? Isn’t this just bee-mediated natural selection? Perhaps, when it comes to our own influence on domesticated species, instead of ‘artificial selection’ it’s better (although, admittedly, slightly clunkier) to think of it as ‘human-mediated natural selection’.
Natural selection works its wonders by weeding out particular variants, while others survive and reproduce – passing genes on to the next generation. Artificial or ‘human-mediated natural selection’ often works in the same way, as farmers and breeders reject certain plants or animals which aren’t as docile, productive, strong, tall or sweet as others. Darwin described this negative selection in the Origin:
When a race of plants is once pretty well established, the seed-raisers do not pick out the best plants, but merely go over the seed-beds, and pull up the ‘rogues’ as they call the plants that deviate from the proper standard. With animals this kind of selection is, in fact, also followed; for hardly any one is so careless as to allow his worst animals to breed.
By pulling up the rogues, sifting out the animals that we don’t want to breed on, or even just looking after certain animals better than others, humans have become powerful agents of natural selection. We’ve roped in a great variety of plants and animals to become our allies in the game of life.
Yet, as we’ll see, sometimes this taming seems to come about almost by accident. And sometimes it appears as though the plants and animals are actually domesticating themselves. Perhaps we’re not as all-powerful as we once believed ourselves to be. Even when we’re setting out deliberately to break in a species, to make it more useful to us, we’re really only unlocking a natural, latent potential to be tame.
The deep histories of plants and animals that are very familiar to us today take us to strange and exotic locations. It’s a good time to be tracing these stories. Arguments have raged on over how each domesticated species sprang into being – from a single origin, a single discrete centre of domestication, or from a wider geographic area, as different wild species or subspecies were tamed and then interbred to form hybrids. In the nineteenth century, Darwin thought that separate wild species could explain the immense variety we see in our domesticates. In contrast, the great, early-twentieth-century plant-hunter and biologist Nikolai Vavilov thought that he could pinpoint discrete centres of origin. Archaeology, history and botany provide plenty of clues, but also leave us with plenty of unresolved questions. With the arrival of genetics – a new historical source – on the scene, we now have a hope of testing competing hypotheses and solving these seemingly intractable puzzles, to uncover the real story of the plants and animals that have become our allies.
The genetic code carried by living creatures contains within it not just the information to make the modern, living organism, but also traces of its ancestry. Looking at the DNA of living species, we can delve into their deep past – thousands, even millions of years back – and glean some clues. We get further insights if we can add genetic clues from DNA extracted from ancient fossils. The first contributions from genetics focused on small fragments of genetic code, but in just the last few years, genetics has broadened its scope to look at entire genomes, and has produced a panoply of surprising revelations about the origins and histories of some of the species closest to us.
Some of those genetic revelations challenge the way that we divide up the biological world. It’s useful – and meaningful – to identify species. That concept embraces a group of organisms that are diagnosably similar to each other – and diagnosably different to others. But the fact that populations undergo evolutionary change, over time, can make drawing boundaries around species quite difficult. We do like to put things in boxes, but biology seems to delight in breaking itself out of such constraints, as we shall learn again and again in this book. How far do lineages have to diverge before they are truly separate species? That’s still a question which taxes taxonomists. When it comes to domesticated animals and plants, some are considered to be subspecies of their wild counterparts, and are given the same species name as their untamed progenitors, and surviving wild cousins – if there are any. Some biologists have advocated using entirely separate species names for domesticates, even if they’re very similar to wild relatives, for ease of reference. The debate over naming shows just how blurred the borderlines are.
In each case, the evolutionary trajectory of the domesticated species – from cattle and chickens to potatoes and rice – was profoundly influenced by becoming intertwined with that of an African ape that had already spread across the world and gone global. These stories are extraordinary and manifold, but I have focused on just ten species. One of those species is us, Homo sapiens. The astonishing transformation we’ve undergone – from wild apes to civilised humanity – suggests that we have somehow tamed ourselves. And only after that happened could we set about taming others. I leave the story of humans to the last chapter. There are many surprises and very new revelations there – hot off the scientific press – but you’ll have to wait for those. Spend time first with nine other species. Each one has had a huge impact on us and our history – and is still important to us today. These domestications are scattered through time and space, so that we’ll understand how human societies have been interacting with plants and animals in various ways, around the world and through history. Their spread around the globe accompanies our own movements – sometimes even fuelling and propelling those human migrations. We find dogs running with hunters; wheat, cattle and rice travelling with the earliest farmers; horses carrying their riders out of the steppe into history; apples stowed in saddlebags; chickens spreading with empires; potatoes and maize crossing the Atlantic on trade winds.
The Neolithic, which first started around 11,000 years ago in East Asia and the Middle East, formed the foundations for the modern world. It was the most important development in the entire history of humanity. We became entangled with other species – in symbiotic relationships that meshed our evolutionary paths together. Farming created the capacity to grow the global human population to immense proportions. Our population is still growing, but we’re pushing at the boundaries of the capacity of this planet to support us. We need to – quickly – develop sustainable ways of feeding at least a billion or two more of us than already live on earth.
Some solutions may be low tech – organic farming has proven much more promising than its detractors suggested, even just fifteen years ago. But high tech may form part of the solution, too. We need to decide how we feel about embracing – or rejecting – the newest generation of genetic modification – tools which can deliver precise genetic adjustments to suit our needs, bypassing the selective breeding our ancestors relied on – or even creating new possibilities that are limited only by our imag
inations.
There are other challenges – with a human population that’s still growing, and four-tenths of land already farmed, we need good evidence to show us the best solution for preserving as many wild species as possible. We’re clever – that’s always been a characteristic of humans. But we need to be cleverer than ever if we’re to find a way of balancing the voracious appetite of a growing human population, and the hordes of tame species we need to survive, with biodiversity and real wilderness. It can sometimes feel as though we humans are a plague on the planet, and it would be a complete catastrophe if the real legacy of the Neolithic Revolution was mass extinction and ecological devastation. We have to hope that there might be a greener future for us – and our allies. Scientific research may not only illuminate the history of our interactions with other species, it provides us with powerful tools to inform the future directions that we can choose to take. Knowing more about the histories of our domesticated species will help us plan for the future.
But let’s start with the past, and see where that takes us. We’re going back far into prehistory to begin the journey, to a world unrecognisable today. A world with no cities, no settlements, no farms. A world still in the chill grip of the Ice Age. Where we meet the first of our allies.
1
DOGS
Canis familiaris
When the Man waked up he said, ‘What is Wild Dog doing here?’ And the Woman said, ‘His name is not Wild Dog any more, but the First Friend, because he will be our friend for always and always and always. Take him with you when you go hunting.’
Rudyard Kipling, ‘The Cat That Walked by Himself’
Wolves in the woods
The sun had set and the temperature had dropped even further. These were the cold, hard months, when the day was so short that there was barely enough time to hunt, to mend the tents, to chop wood for the fire. The temperature outside never rose above freezing. Towards the end of winter, things always got difficult. The dried berries from last summer would eventually run out. Then there was meat for breakfast, meat in the middle of the day, meat for supper. Mostly reindeer meat, of course. But occasionally, just for a change, a bit of horse or hare.