Domesticated: Book review

Posted 25 July 2015 by

A number of years ago, I found a family of raccoons living in my chimney.1 I got them out by dropping a trouble light down the flue and turning it on for a few days. According to Richard C. Francis, in his splendid book, Domesticated, animals such as raccoons living in urbanized areas represent the first step toward domesticating those animals. The full title of the book is Domesticated: Evolution in a Man-Made World, and Francis shows in considerable detail how various animals became domesticated: dogs, cats, pigs, sheep and goats, reindeer, camels, horses, rodents, and perhaps humans, as well as other predators such as raccoons and ferrets. Each scenario is slightly different, each seems well documented, and each has just a little bit of just-so story in it. The audience for the book is not completely clear. I think the author thinks that the book is written for the lay reader, but at times it got a little hairy, and I recommend that, if you are not a biologist, you keep your computer nearby. Or, if you are younger than I, your smart phone. Indeed, after getting through 50 or so pages of the complimentary copy I received, I bought a Kindle edition, precisely so that I could more easily look up terms that were unfamiliar or not entirely familiar. Lest this paragraph be taken as a criticism, let me make clear that the effort was wholly worthwhile. Francis begins with the now well known domestication of foxes by Dmitry Belyaev in Siberia. Belyaev and his colleagues selected foxes, as Francis puts it, "for one trait and one trait only: the capacity to tolerate human proximity without fear or aggression." In approximately 50 years, they bred foxes that were as tame as many dogs. But there were concomitant physical changes: hair became mottled or piebald, ears flopped, tails curled, snout and limbs shortened, and face broadened, for example. Additionally, brain volume and sexual dimorphism were reduced. Many of the same physical changes may be seen in domesticated dogs, cats, horses, cattle – and all are a direct result of selection for tameness. Such by-products are a general feature of evolution and are a form of convergent evolution resulting from various homologies that more or less guarantee that all domesticated mammals will evolve similar traits. The raccoons in my chimney are probably already self-selected for tolerance of human beings. Wolves probably self-selected in roughly the same way: perhaps they began to domesticate themselves by feeding on scraps left by early humans, as the raccoons occasionally feed on my garbage. Wolves in different geographical areas evolved into landraces, sort of proto-breeds that eventually developed into what we know as breeds. I was surprised to learn that the concept of breed is only a century or so old. British kennel clubs, beginning in the 1870's, hyper-selected for various traits, such as the snout of a bulldog. Francis says that they routinely mated a champion male with his own female offspring and remarks somewhat archly that the Victorian aristocrats ultimately responsible for such incestuous relationships may have been desensitized as a result of their own pedigrees. Besides causing inbreeding, such selection also caused serious physical and genetic defects in virtually all purebred dogs. Not to mention that thoroughbred horses, which Francis deals with in a later chapter, are at an evolutionary dead end: they are infertile, and their speed has not improved in 50 years. There are no master races; they need to be mongrelized. Cats also enjoyed a commensal relationship with humans, probably after the mouse was introduced into the wild cats' region. Although humans consider cats somewhat standoffish, Francis notes that feral housecats remain far more tame and far more gregarious than their wild ancestors. Like dogs, cats have been bred to have various skeletal deformities, a practice that Francis considers "unconscionable." Pigs may have been domesticated similarly to dogs, but it is also possible that pigs, cattle, sheep, goats, and horses were domesticated by "human management of wild populations," wherein wild animals were first herded, then bred. Cows, in particular, descend from the wild aurochs, a large, fierce beast that Caesar compared, with some hyperbole, to elephants. Regarding the aurochs's ferocity, Francis writes,

[N]o matter how tame these early domesticates were, by auroch[s] standards, you would still need to be a lot braver than a bull leaper to push their calves aside and pull on their teats.

(What's not to like about a book that regularly comes up with quips like these?) Francis seems to have forgotten, however, that elephants have been domesticated, and he writes that the aurochs is the largest domesticated animal. Oddly, he thinks (incorrectly) that the singular of aurochs is auroch. In fact, the singular is aurochs; the word is cognate with ox (think ur-ox). It is odd that the copy editor did not catch this mistake, because the book seems to be generally well prepared (we will not, however, discuss the use of grizzly where grisly was meant). Sheep and goats (Francis prefers goats), reindeer, camels, horses, rodents: Francis covers them all, often beginning a chapter with a curious anecdote. Horses, for example, were originally domesticated for their meat; only later, after other meat sources were available, was the horse used for transportation and warfare. The horse's status has risen so sharply that most Europeans and their cultural descendants "would be about as aghast at the thought of eating horse meat as they would dog meat." Francis devotes 2 chapters to the question whether humans domesticated themselves. The argument is long, and I am afraid you will have to read it for yourself, but it depends in part on the argument that humans, like other domesticated animals, are neotenous, that is, the adult animal retains juvenile features, such as big eyes. I got slightly bogged down in one chapter by the profusion of terms like hominid, hominin, hominine, and hominoid (which I think of as homonym-oids). The second of these chapters asks whether human hypersociality came as the result of self-domestication by way of natural selection for tameness. Answer: "It ain't necessarily so"; Francis wants more evidence. The final chapter, except for an epilogue, is called "The Anthropocene" and asks how an utterly obscure, bipedal, nearly hairless ape could in a mere few hundred thousand years come to dominate the planet and indeed be responsible for the most recent mass extinction. I cannot go into detail here, but I am left with the feeling that it was mostly "cultural evolution," with biological evolution following thereafter – as when herdsmen begin to use dairy products (cultural evolution) and only thereafter does an allele for lactose tolerance predominate (biological evolution).
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Appendix 1. I resolved not to read the appendixes; generally I do not like appendixes or endnotes1 and think that a topic should be incorporated into the book if it is important enough and dropped if it is not (excluding very abstruse derivations and whatnot). Nevertheless, I began to read the appendixes and was treated to a discussion of the need for a new synthesis that gets away from the gene-centered view popularized by Richard Dawkins, a serious and hard-hitting critique of evolutionary psychology, and also some boring stuff. Appendix 2. As one of the self-appointed guardians of the modern metric system, I disliked the book's use of "mya" for "million years ago"; if anything, the usage should have been "Mya." But that is not really satisfactory either, because "y" and "a," though not SI symbols, are both commonly used as a symbol for "year." I probably would have used "Ma" for "megannus," since "year" is Anglocentric. In addition, when he means tens or hundreds of thousands of years, the author uses "BP," presumably meaning "before present," which is arguably OK, but not consistent with the previous usage. At least once, he used "CE," which is perhaps more useful than "BP" when we are discussing more or less historical times, but again is inconsistent.
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1 My son also had a raccoon in his chimney; unfortunately, his died there, with unfortunate consequences involving maggots. I really did not want to tell you that, but I wanted to make a point about the endnotes. The book has a significant number of endnotes. Many of them simply cite a reference, but others have content. I find it very distracting to have to stop my reading and go to an endnote. Part of the art of writing is culling: if something was worth telling, the author should have worked it into the text or, otherwise, killed it.

34 Comments

Paul Burnett · 25 July 2015

Does the book discuss bees, which have also been domesticated for millennia?

https://me.yahoo.com/a/JxVN0eQFqtmgoY7wC1cZM44ET_iAanxHQmLgYgX_Zhn8#57cad · 25 July 2015

I guess if we domesticated mice, why not domesticate other vermin, like raccoons?

Just forget about rats though. Oh, right, who ever decided to do that?

Glen Davidson

Matt Young · 25 July 2015

Does the book discuss bees, which have also been domesticated for millennia?

Nope, no bees either. So he may have omitted the largest and smallest domesticated animals. Unless you count certain whales, I suppose.

harold · 25 July 2015

Does the book offer a definition of domestication?

All traditional domesticated animals have traits that raccoons and foxes don't share.

First of all they all do one or more of the following -

1) Provide an efficient source of meat for humans.

2) Provide a material humans use for food or textiles - wool, eggs, milk, etc.

3) Do a job for humans. The ones that do a job - horses (their job is now
mainly anachronistic), dogs (still used for hunting and guarding), cats (still hunt vermin), and ferrets (still hunt vermin) - also tend to become friendly pets for humans. I suppose it's not surprising that we get friendlier with them when eating them is less of the reason for keeping them around.

Cattle are the only ones I can think of that routinely do it all - you can eat them as beef, use them as a source of dairy products, use their hides for textiles, oxen will pull things for you, and dairy cows tend to bond in a somewhat friendly manner.

I don't see how raccoons, or pigeons, or cockroaches, or house mice, fit into this. Sure, they're species that can tolerate humans. So are deer in many areas. Driving through a rich suburb a while ago I saw a doe and fawn calmly walking around. Staten Island has a large population of wild turkeys. Squirrels do tend to flee at that last moment but are pretty arrogant around humans.

However, tolerating humans is necessary but not sufficient for domestication.

I'm quite tolerant of non-rabid raccoons making use of garbage that I don't want any more, as long as they keep out of sight, but it's a far cry from domestication.

Matt Young · 25 July 2015

I do not remember whether the book defines domestication explicitly, but I would be surprised if it did not. At any rate, neither Francis nor I said that raccoons are wholly domesticated. He (we) said that tolerating humans and living close by was the first step. Domestication is more than merely tolerating humans or living commensally with them.

I do not see why we cannot consider an animal domesticated even if it serves no useful (to us) purpose. I suspect that horses once "did it all" but westerners are squeamish about eating them.

harold · 25 July 2015

Matt Young said: I do not remember whether the book defines domestication explicitly, but I would be surprised if it did not. At any rate, neither Francis nor I said that raccoons are wholly domesticated. He (we) said that tolerating humans and living close by was the first step. Domestication is more than merely tolerating humans or living commensally with them. I do not see why we cannot consider an animal domesticated even if it serves no useful (to us) purpose. I suspect that horses once "did it all" but westerners are squeamish about eating them.
That's why I think it might make sense to define the term. We have some "pure pet" or perhaps "pure captive" relationships with animals. We put birds in cages because we enjoy their appearance and vocalizations. However, I think that the concept of domestication probably fits more with animals that were useful from the beginning. Wasteful "domestication" of a species that provided no benefit would not have been an option for earlier humans. Certainly, our Anglophone culture puts a taboo on eating dogs, horses, and cats. These are animals which traditionally do useful "jobs" over a moderately long life span, expressing individual personalities and bonding strongly with humans in the process. In addition to the empathy their behavior evokes, eating them may have been a symbol of harrowing circumstances. If you have to eat the horse that pulls your cart or the dog that helps you hunt and guards your house, it's a sign that short term distress has forced you to sacrifice long term benefits (some European cultures eat horse meat more freely, but the meat of elderly horses that are no longer useful for work - no culture traditionally slaughtered good working horses for food, not even hunter gatherer horse cultures). Hence a cultural resistance to this behavior, perhaps. I strongly endorse this taboo. Sometimes, traditions are best changed, and at other times, it makes sense to continue them.

harold · 25 July 2015

There are animals we take pure advantage of - the ones we hunt, which gain nothing from the relationship (no, not "population control", that's only a factor because we killed off the carnivore competition for hunting them, and they only evolved to need it because of carnivores in the first place).

There are the ones who take advantage of us. Cockroaches and house flies provide no advantage to us whatsoever, for example.

Then there are the few we have a strong symbiotic relationship with. We feed them and make it easy for them to breed, they provide back a benefit. In the modern world it may be mainly recreation and emotional bond but historically, in all cases, it was outright physical benefit. Those are the ones I call domesticated.

Until raccoons can figure out something useful to do for me, they're no closer to being domesticated than house mice, which have probably been living around us since the paleolithic and have never become "domesticated". Sure a raccoon might want to live in my dwelling and eat some of my food, but that's a one way street.

Now raccoons have evolved ability to tolerate and deal with humans, and that is an interesting trait and worth studying. It's just not "domestication" as I see it.

https://me.yahoo.com/a/JxVN0eQFqtmgoY7wC1cZM44ET_iAanxHQmLgYgX_Zhn8#57cad · 25 July 2015

harold said: There are animals we take pure advantage of - the ones we hunt, which gain nothing from the relationship (no, not "population control", that's only a factor because we killed off the carnivore competition for hunting them, and they only evolved to need it because of carnivores in the first place). There are the ones who take advantage of us. Cockroaches and house flies provide no advantage to us whatsoever, for example. Then there are the few we have a strong symbiotic relationship with. We feed them and make it easy for them to breed, they provide back a benefit. In the modern world it may be mainly recreation and emotional bond but historically, in all cases, it was outright physical benefit. Those are the ones I call domesticated. Until raccoons can figure out something useful to do for me, they're no closer to being domesticated than house mice, which have probably been living around us since the paleolithic and have never become "domesticated". Sure a raccoon might want to live in my dwelling and eat some of my food, but that's a one way street. Now raccoons have evolved ability to tolerate and deal with humans, and that is an interesting trait and worth studying. It's just not "domestication" as I see it.
Except that the house mouse has been domesticated. I'm not sure what the benefit was, possibly just as a hobbie for rich dilletantes, as they came up with "fancy mice"? Science benefited from this, but (as a discipline) didn't instigate it. I suspect that raccoons would be a good deal more trouble and expense than house mice, though, and wouldn't lend themselves to being readily "fancy," thus I don't think that the house mouse is any model for "raccoon domestication." Glen Davidson

https://me.yahoo.com/a/JxVN0eQFqtmgoY7wC1cZM44ET_iAanxHQmLgYgX_Zhn8#57cad · 25 July 2015

I found this about domesticated house mice:
Mouse History | Mouse Trivia Domesticated mice are descendants of the house mouse or scientific name ‘Mus musculus’. The house mouse originated in Asia but are now found all over the world, particularly where people are present. The earliest domesticated mice were kept in the royal palaces of Japan and China. Mice were also used in various writings such as Aesops Fables. Mouse association with humans goes back to the dawn of history. In biblical times plagues of mice were recorded and ancient egyptians kept mice as pets believing they had super natural powers.
https://animalcorner.co.uk/mice-history-trivia/ At least they're fine for feeding snakes--though I'm not sure why people keep those, either. Glen Davidson

Matt Young · 25 July 2015

I just searched the beginning of the book, and I am afraid he defines domestication the way Potter Stewart defined pornography. But he surely means a closer relationship than the commensal relationship between the raccoon and the human, which you keep harping on. No one ever said that the raccoon living in the storm drain was domesticated, but the relationship between those raccoons and humans is likely similar to the early relationship between humans and wolves. Eventually the wolves that best tolerated humans evolved into village dogs, which live and forage in and around human settlements, to dogs that live with humans, not just around them. But no one called the wolves domesticated just because they ventured into human territory.

Robert Byers · 25 July 2015

Its interesting although I've seen these points many other places as because of being a creationist I note how, unrelated to selection, there was these changes in these creatures bodies.
WHY is it convergent evolution that is going on in bringing like results to unlike domesticated creatures? I don't see what is being selected here? Instead I say its innate triggers, I don't know how, that bring like results. No convergent evolution going on at all even if it did ever go on anywhere. Of coarse I don't think it did.

I understand they find Egyptian pictures, 2500BC, of Dalmatian dogs and so why is that not a breed. in fact they always had big hunting dogs and so on. so breed is a old concept surely.

David MacMillan · 25 July 2015

Yes, they did have many breeds of dogs in 2500 BCE, basically most of the same breeds we have today. Which is very odd if all those breeds had to be bred in the span of just a couple hundred years after the Flood...yet they have barely changed one iota in the meantime.

Rolf · 26 July 2015

Now I know the why and how of the phenomenon of Mr. Robert Byers' always beat science:

Knowitall

DS · 26 July 2015

Of coarse booby still hasn't learned the difference between "of course" and "of coarse", even though he has been repeatedly corrected here many times on that very issue. It is a old concept surely. I can only conclude that either he is incapable of learning or he is being deliberately obtuse. Either way, he has nothing of substance to contribute to any scientific discussion. Why does he think he knows more than all the experts when he can't even figure out how to use a question mark. (I did that on purpose).

AS for the dogs, there was an article on the subject recently:

Scientific America (2015) From Wolf to Dog 313(1):60-67

The article discusses recent genetic evidence, including evidence of gene flow between lineages.

harold · 26 July 2015

https://me.yahoo.com/a/JxVN0eQFqtmgoY7wC1cZM44ET_iAanxHQmLgYgX_Zhn8#57cad said:
harold said: There are animals we take pure advantage of - the ones we hunt, which gain nothing from the relationship (no, not "population control", that's only a factor because we killed off the carnivore competition for hunting them, and they only evolved to need it because of carnivores in the first place). There are the ones who take advantage of us. Cockroaches and house flies provide no advantage to us whatsoever, for example. Then there are the few we have a strong symbiotic relationship with. We feed them and make it easy for them to breed, they provide back a benefit. In the modern world it may be mainly recreation and emotional bond but historically, in all cases, it was outright physical benefit. Those are the ones I call domesticated. Until raccoons can figure out something useful to do for me, they're no closer to being domesticated than house mice, which have probably been living around us since the paleolithic and have never become "domesticated". Sure a raccoon might want to live in my dwelling and eat some of my food, but that's a one way street. Now raccoons have evolved ability to tolerate and deal with humans, and that is an interesting trait and worth studying. It's just not "domestication" as I see it.
Except that the house mouse has been domesticated. I'm not sure what the benefit was, possibly just as a hobbie for rich dilletantes, as they came up with "fancy mice"? Science benefited from this, but (as a discipline) didn't instigate it. I suspect that raccoons would be a good deal more trouble and expense than house mice, though, and wouldn't lend themselves to being readily "fancy," thus I don't think that the house mouse is any model for "raccoon domestication." Glen Davidson
Yes, good point about mice. I do stand by my original point about defining what we mean by domesticated. Mice may have been kept as pets for quite a long time; Wikipedia claims that this work mentions mice kept as pets https://en.wikipedia.org/wiki/Erya Mice now fulfill the criteria of "doing something useful for us". In fact an argument could be made that they're the most useful species of all. But as I noted, I still think we should be clear, when talking about domestication, whether we mean the rigorous process of creating a mutual useful relationship, or whether we merely mean making animals tolerant of humans. After all, many wild parrot species are already "domesticated" in the sense that if captured they'll live around humans and socialize with us without fear (of course I condemn capture of wild parrots for this purpose; I'm just making a point). And many species including the insects I mentioned both live among us and are fed by us, but not because we want them (also more or less the current state of raccoons). So it has to be more than either of those things.

Just Bob · 26 July 2015

Would our human-specific intestinal flora count as 'domesticated'? They do vital work for us, and many of them are probably not viable outside of a human environment. They have adapted to the niche of the human gut. We didn't intentionally domesticate them (nor were we even aware of them), but we didn't intentionally and systematically cause the changes in the larger plants and animals that we domesticated in ancient times, either.

I demand proper recognition for the little guys!

Sylvilagus · 26 July 2015

For what its worth, my Merriam Webster from 1993 gives the second definition of "grizzly" as a variant spelling of "grisly."
So does my 1977 edition. I also found a citation for the OED stating the same, though I don't find that in the online version I just checked.

Matt Young · 26 July 2015

For what its worth, my Merriam Webster from 1993 gives the second definition of “grizzly” as a variant spelling of “grisly.”

So (not surprisingly) does my 1993 edition, but MW Online gives no such variant usage. Most of the time, "variant usage" means "error that has become common." Yes, I know, I will get into trouble for that remark, but I still think a copyeditor should have used "grisly" unless the meaning was "gray haired."

Michael Fugate · 26 July 2015

It is also worth noting that domesticating animals and plants changed us as much as we changed them. Lactose tolerance is just one example.

Joe Felsenstein · 26 July 2015

Over 50 years ago I spent several summers in the summer programs of the Jackson Laboratory in Bar Harbor, Maine, where all work was with mice. I then had a job in college working in the "mouse room" of a developmental biologist. So I got a lot of experience with mice.

Lab mice are descended from domestic mice kept by mouse fanciers, the lab strains originating about the 1920s. They are domesticated in the sense that they are far less aggressive and hyperreactive. The saying was that if you put a lab mouse and a wild mouse in a cage and then took the top off, an instant later you would have only the lab mouse in the cage.

When a mouse escapes, it is much more likely to be killed in the ensuing pursuit, or maybe even succeed in getting away. This makes for a strong artifical selection for placidity. Similarly, a mouse that bites its keeper has a dramatically lower fitness.

Lab mice show strong behavioral differences from wild mice. For all that, they show no desire to cuddle or willingness to fetch the newspaper.

fusilier · 27 July 2015

A Niggle:

Somewhere I once read that working elephants are not domesticated. Instead they are "tamed." The distinction had to do with captive breeding and other physiological/anatomical changes.

So the claim in the book that the aurochs is the largest _domesticated_ animal might follow that notion.

YMMV, to be sure.

fusilier

James 2:24

eric · 27 July 2015

Just Bob said: Would our human-specific intestinal flora count as 'domesticated'?
I think they probably count more as a symbiote than a domesticated creature. The difference being the level of interdependence (symbiote implies more dependence, such as when one dies, the other most often dies too).

Matt Young · 27 July 2015

Somewhere I once read that working elephants are not domesticated. Instead they are “tamed.” The distinction had to do with captive breeding and other physiological/anatomical changes.

That seems like a fair distinction to me (a nonbiologist, to be sure). And it shows the importance of precise definitions.

Just Bob · 27 July 2015

eric said:
Just Bob said: Would our human-specific intestinal flora count as 'domesticated'?
I think they probably count more as a symbiote than a domesticated creature. The difference being the level of interdependence (symbiote implies more dependence, such as when one dies, the other most often dies too).
Hmm, interesting distinction. In a sense, perhaps we have domesticated each other.

Robert Byers · 27 July 2015

As a YEC creationist I think this makes a case for a paper on this issue.
Did all the reduction etc traits that happen to domesticated animals come from evolution?
how did selection bring these results? The author says it the breeding for tameness that did it. yet why? why should tame equal floppy ears etc. That was not the goal of selection.
These creatures had a biological change in thier bodies wothout selection on mutations or selection for these changes. jUst a unexpected result. Like the foxes case.
therefore since it always happens then it must mean there is another mechanism being triggered to bring these changes.
the selection for tameness, if that really happened much after a time, triggers some other mechanism in the bodies.
if in domestication then why not greater in nature, like darwin talked about, .
I think there is a option here that domesication changes show a non evolutionary influence in bringing body changes.
Something for a creationist or sharp researcher to investigate.
Looking in our cats eyes we have missed a cute criticism of evolutionism.

Sylvilagus · 28 July 2015

Robert Byers said: As a YEC creationist I think this makes a case for a paper on this issue.
This should prove entertaining.
Did all the reduction etc traits that happen to domesticated animals come from evolution?
That's actually a good question. In fact, one of the very questions the book is addressing. Could be the start of an actual research program.
how did selection bring these results? The author says it the breeding for tameness that did it. yet why? why should tame equal floppy ears etc. That was not the goal of selection.
Amazing... An actual observation. A good one too. Why ARE traits like floppy ears linked with selection for "tameness"? The research program is being focused and refined....
These creatures had a biological change in thier bodies wothout selection on mutations or selection for these changes. jUst a unexpected result. Like the foxes case. therefore since it always happens then it must mean there is another mechanism being triggered to bring these changes. the selection for tameness, if that really happened much after a time, triggers some other mechanism in the bodies.
Good... Recognizes a mechanism is needed..... Now to propose one and design an experiment. . We are actually close here to hypothesizing how real genetics systems work. I think we are about to witness the discovery of chromosome structures and gene linkage ....
I think there is a option here that domesication changes show a non evolutionary influence in bringing body changes. Something for a creationist or sharp researcher to investigate. Looking in our cats eyes we have missed a cute criticism of evolutionism.
Oops! Missed it. Stopped looking just when he was about to learn some real science. Got distracted by that cute cat. Damn, science is hard. Easier just to play with the cat. And that ball of yarn. Gee it's fun. Praise God!

RCF · 28 July 2015

Hi all. And thank you for the thoughtful review of "Domesticated Matt.
A few thoughts on some recurrent questions.

1. Why I did not define domestication. Surprisingly, there is no widely accepted definition and I find them all inadequate. For example, Diamond defines domestication as something like genetic modification to human ends. This works for the last stages of domestication, when it is entirely under conscious human control, but not for most of the domestication process, which is often initiated by the domesticating species for their own self-interest. This is often referred to as self-domestication. Wolves were originally self-domesticated and continued to be so long after they approached the doggy state. Cats remain largely self-domesticated. For example, most domestic cats mate with whoever they damn well please.

I treated domestication as an evolutionary process not a well-defined end state. As such there is a continuum in the degree of domestication. So what criterion trait best characterizes this continuum. Tameness is the primary trait under selection during domestication in mammals. Floppy ears, shortened snouts, depigmentation (white coloration), reduced brain size and reduced sex differences are all largely correlated byproducts of selection for tameness. Some elements of this domestication syndrome were also exaltations for life the human environment. A different possible criterion for the domestication continuum is the degree to which humans control reproduction through mate choice. By this criterion, dogs are more domesticated than cats, which are more domesticated than reindeer.

In retrospect, I see now that I should have at least offered my own definition of domestication, or the best criterion for the domestication continuum, however inadequate.

With the continuum in mind, consider elephants, lab mice and raccoons.

2. Are elephants domesticated. The short answer is no. Like all evolutionary processes domestication requires genetic alterations. There is no evidence of such for Asian elephants.

3. The lab mouse is a domesticated form of the house mouse, which is a wild human commensal. The lab mouse genome contains contributions from three of the four house mouse subspecies, two of which were already present in fancy mice (also domesticated house mice). When the third subspecies was interbred with fancy mice, we got lab mice.

4. What about raccoons. Urban raccoons have certainly become tamer than their forest counterparts but raccoons have enormous behavioral phenotypic plasticity. To have entered the domestication continuum, we must demonstrate that the behavioral alterations in urban raccoons extend beyond what can be achieved through phenotypic plasticity alone. The jury is still out. As human commensals, raccoons, like house mice are certainly vulnerable to future domestication, as are European badgers and perhaps even some kangaroo populations, such as those around Canberra.

5. The taxonomic scope of this book was limited to mammals, not because I am mammal-centric--I am currently writing about yeast domestication for beer and winemaking--but in the service of the main evolutionary theme of this book, which is evolutions conservatism. Why do all domesticating mammals tend toward the suite of traits called the domestication syndrome or domesticated phenotype. On standard adaptationist accounts this convergence is caused by similarities--and hence selective pressures-- in the human environment. If we look to evolution's conservative side, however, as demonstrated by evo devo and comparative genomics, we see that this is only part of the story. Deep homologies shared by all mammals by virtue of descent from a common ancestor go a long way toward explaining why all mammals tend to respond similarly during domestication. The homologies I discussed in the book included the stress response (hypothalamic--pituitary-adrenal axis, the limbic system of the brain (which mediates emotional behavior), and the migration of neural crest cells during development.

6. I had an excellent copy editor who saved me much embarrassment. The mistake re "aurochs" versus "auroch" is on me.

Henry J · 28 July 2015

Re "Good… Recognizes a mechanism is needed.…. Now to propose one and design an experiment. . We are actually close here to hypothesizing how real genetics systems work."

My guess would be that with selection for a few particular traits being emphasized, that allows increased amounts of genetic drift in DNA for other traits that have ceased being a significant factor in reproductive success.

Robert Byers · 28 July 2015

This comment has been moved to The Bathroom Wall.

DS · 29 July 2015

Sure booby. Hypothesis all you want. All it comes down to is "i dont wannna believe it, so i aint" a gonna". How about testing your hypothesis? Has that ever entered into your thought processes? Why don't you intelligently design an experiment to distinguish between the predictions of evolution and your hypothesis? Do the experiment and report your results in a scientific journal. Then we can talk. Until then, you lose.

Matt Young · 29 July 2015

Mr. Byers has exceeded his allocation by 2, and his comment has been sent to the Bathroom Wall. Please reply to him there (or not).

Matt Young · 29 July 2015

On the other hand Science reports that city birds are more aggressive than country birds. Turns out that certain sparrows became more aggressive when they had more food to defend. Note to creationists: researchers tested that hypothesis by providing country birds with more food and noted that they became more aggressive than before.

Jason Mitchell · 29 July 2015

I have not read the book - but I have seen studies (that RCF refers to above, I think) that demonstrate the link between pigment cells and behavior. It turns out that Melanin and Adrenaline producing cells have similar/connected developmental pathways and that selecting for one (tameness - lower adrenaline) has an effect on the other (pigment cell distribution/ piebald/spotted phenotypes) IIRC there are also demonstrated developmental links with some skeletal features and neurological pathways (tameness and floppy ears etc.) That this suite of phenotypes (domestication syndrome) is seen across many mammalian species is consistent with common ancestry (and not consistent with them being unrelated/ specially created 'kinds').

also for the lurkers out there: Symbiosis (as the term is used by biologists) is not only mutualism (where both species benefit from the relationship) but also includes parasitism and predation. I've often seen domestication described as symbiosis where humans benefit occurring simultaneously with selective pressure on the domesticated species. (or more simply domesticated species are those that we bred for our benefit which are no longer the same as their wild counterparts)

eric · 29 July 2015

RCF said: As human commensals, raccoons, like house mice are certainly vulnerable to future domestication, as are European badgers and perhaps even some kangaroo populations, such as those around Canberra.
Not just Canberra. I lived in a Melbourne suburb many years ago, and we used to get them regularly grazing the public park across the street - in larger groups and much more out in the open, during the day, than what I see in US suburbia with deer. Though I wonder if that has more to do with type of grazing than domestication. IIRC, deer prefer woody plants over grasses, so 'roos being more visible may have more to do with diet then where they sit on the scale of domestication. I'm not sure we're ready for raccoons. We've already got cats and dogs managing us; add in raccoons, and human civilization would quickly become wall to wall PetCos and chew toy stores.