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How exactly have dogs become domesticated?
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Shrink
macrumors G3
Although there is some debate about the issues, Lamarckian Inheritance (the genetic transmission of acquired characteristics) is still, to my knowledge, not in any useful way been confirmed, and is still discredited.. So the best theory would be domestication would be a function of selective breeding and postpartum conditioning.
I'm sure there evolutionary biologists out there who discuss this far more cogently than I.
This is an interesting discussion.
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strider42
macrumors 65816
Lamarkian inheritence is not just not mainstream, its completely discredited as it makes no sense based on the knowledge we now have about genetics and inheritance.
Memories do not get passed on in any kind of inheritance. Dogs, and any organism, don't "remember" their ancestors experiences or dispositions.
There are lots of theories about how exactly dogs became domesticated. One is that wolves started hanging around humans to eat their scraps and/or garbage. This sets up a selection pressure for friendlier wolves. They get adopted as pets (tamed), which furtheres the domestication selection pressures as breeding starts being controlled. once you control breeding, you select for friendly animals that bond closely and readily with other animals (us in this case). You can select for various traits about their bodies and demeanor and even intelligence to meet the function you want them for (herding, digging, hunting, chasing rats, etc, these are all instinctual behaviors in many dog breeds). We've even changed how their brains works. Dogs are one of the very few animals that understand what it means whne a human points at something (chimps don't get that at all), and they read human faces better than just about any animal as well. Again, all from rewiring their brains through selective breeding.
this may have happened in more than one place. Some think chihauhas might even come from foxes instead of wolves.
Check out the russian domesticated fox experiment. its fascinating. Two lines of foxes selectively bred over a few decades. One set is basically like dogs, complete with floppy ears and cute markings. very loving, affectionate animals. The other line was bred to be super violent and hate any humans from coming near them.
I would also recommend reading guns, germs and steel. A great book that has a large section on domestication, how it may have happened, and why some animals can be domesticed and others can't. In short, dogs are perfect for domesticating because they don't panic, have a heirarchical pack structure, are omnivores, and aren't too large.
But in short, its entirely selective breeding.
mobilehaathi
macrumors G3
It is pretty much the result of selectively breeding out traits that we did not want. Although we don't understand too much about the genetics of behavior, we have been successfully domesticating animals for thousands of years. It is the original genetic engineering.
Incidentally, there was an interesting paper recently published in Science on an adaptive behavior that has evolved in cockroaches. Some roaches have evolved to taste glucose (which is often used in roach traps as a bait) as bitter, effectively modifying their behavior to avoid these traps.
Incidentally, there was an interesting paper recently published in Science on an adaptive behavior that has evolved in cockroaches. Some roaches have evolved to taste glucose (which is often used in roach traps as a bait) as bitter, effectively modifying their behavior to avoid these traps.
Shrink
macrumors G3
The only reason I mentioned it was because of the study done with planaria many years ago.
Since I have no expertise in this area, I don't know if the study was ever replicated, or just discredited. I know that Lamarckian genetic inheritance is a discredited theory, but I am unsure as to what the follow up was to the planaria study.
balamw
Moderator emeritus
Don't panic
macrumors 603
behavioral traits have genetic components and can most certainly be selected for/against.
if you have a young kid and two dogs, one of which repeatedly tries to bite your kid, which of the dogs do you keep?
if you have a young kid and two dogs, one of which repeatedly tries to bite your kid, which of the dogs do you keep?
Fascinating!
"Would wolves, having been raised by humans, demonstrate social-cognitive skills that approached the sophistication of dogs? Or is social-cognitive aptitude encoded in dogs genes, a direct result of domestication?
In one simple task, a plate of food was presented to the wolf pups (at 9 weeks) or to the dog puppies (both at 5 weeks and at 9 weeks). However, the food was inaccessible to the animals; human help would be required to access it. The trick to getting the food was simple: all the animals had to do was make eye contact with the experimenter, and he or she would reward the dog with the food from the plate. Initially, all the animals attempted in vain to reach the food. However, by the second minute of testing, dogs began to look towards the humans. This increased over time and by the fourth minute there was a statistical difference. Dogs were more likely to initiate eye contact with the human experimenter than the wolves were. This is no small feat; initiating eye contact with the experimenter requires that the animal refocus its attention from the food to the human. Not only did the wolf pups not spontaneously initiate eye contact with the human experimenter, but they also failed to learn that eye contact was the key to solving their problem."
"Would wolves, having been raised by humans, demonstrate social-cognitive skills that approached the sophistication of dogs? Or is social-cognitive aptitude encoded in dogs genes, a direct result of domestication?
In one simple task, a plate of food was presented to the wolf pups (at 9 weeks) or to the dog puppies (both at 5 weeks and at 9 weeks). However, the food was inaccessible to the animals; human help would be required to access it. The trick to getting the food was simple: all the animals had to do was make eye contact with the experimenter, and he or she would reward the dog with the food from the plate. Initially, all the animals attempted in vain to reach the food. However, by the second minute of testing, dogs began to look towards the humans. This increased over time and by the fourth minute there was a statistical difference. Dogs were more likely to initiate eye contact with the human experimenter than the wolves were. This is no small feat; initiating eye contact with the experimenter requires that the animal refocus its attention from the food to the human. Not only did the wolf pups not spontaneously initiate eye contact with the human experimenter, but they also failed to learn that eye contact was the key to solving their problem."
balamw
Moderator emeritus
T'hain Esh Kelch
macrumors 604
No. It would definitely make it friendlier, but that doesn't mean that its offspring behave the same way.
The one that learns to fetch the morning news paper. 😉
Dr McKay
macrumors 601
I know it's offspring won't behave in that way, but odds are it's offspring will be born into domestication too.
ValSalva
macrumors 68040
I thought wolves that were the most docile were bred with each other over many generations.
Each generation the most docile and approachable ones were bred with each other.
Eventually they became friendly towards humans but also other traits which were not specifically bred for became expressed such as variations in color. It's as though through this type of inbreeding their puppy traits remained through adulthood.
There have been very interesting documentaries about this. I wish I could remember the name of one of them. Fascinating topic.
Each generation the most docile and approachable ones were bred with each other.
Eventually they became friendly towards humans but also other traits which were not specifically bred for became expressed such as variations in color. It's as though through this type of inbreeding their puppy traits remained through adulthood.
There have been very interesting documentaries about this. I wish I could remember the name of one of them. Fascinating topic.
strider42
macrumors 65816
that's not what domestication is. Domestication is, by definition, selective breeding to bring about genetic changes in an animal to serve some purpose. being tamed is very different than domestication. Taming an animal, then keeping their offspring, breeding for traits through generations...thats what domestication is. If you don't control the breeding, then you still just have wild animals who are tamed.
There are many tamed animals in service to humans. Elephants for instance are often tamed. They are in no way at all domesticated. Many animals we would love to domesticate are nearly impossible to do so with.
Domestication is, by definition, selective breeding. The traits animals get (being more docile, etc) is genetic. There is literally no other mechanism for offspring to be like their parents. You can tame some animals, but their offspring will not be tame because of that. If you are keeping their offspring, you will start selecting for the ones that suit your needs the best. That is how domestication starts. But its still 100% genetic.
The first dogs were Grey Wolves, which tens of thousands of years ago, became self-domesticated as they were attracted to the first sites of permanent human habitation. There is genetic and archaeological evidence showing that humans domesticated wolves on more than one occasion, dating back as far as 15,000 years ago. Early humans domesticated these wolves and were provided with a guard animal, a source of food, fur, and a beast of burden.
jasonvp
macrumors 6502a
As has already been mentioned, the most popularly-accepted explanation for domesticated canines started with what were called camp wolves thousands and thousands of years ago. These were the wolves that slummed around at the outskirts of our camps (before we actually had permanent settlements), cleaning up our scraps. When we packed up or deserted our camps, the wolves would tag along at a distance.
Years and generations passed, and the resulting camp wolves still looked very much like their non-camp brethren. But they'd began losing their ability to hunt. When we realized they could be advantageous to have around, we found the less aggressive versions and, for lack of a better word, adopted them into our camps. The meaner ones were probably shunned or even killed. This process repeated itself over many more years until the domesticated canine basically acted and looked nothing like its wolf predecessor.
The Eugenics experiment that is today's dog, more or less, got its kick in 18th century Europe. There, with leisure time available to many, "customizing" the dog to look and act in specific ways became a hobby, and then an industry. And it's been with us ever since.
Another interesting and related test has been done where a piece of meat was hidden under one of 2 paper cups. A human was sitting behind the cups and would know which cup the meat was hidden under. Wolves and dogs were then given a chance to find it. It's understood that a wolf's nose is substantially better tuned than a domesticated canine's is, so they should have had a nearly 100% success rate. They didn't. The domesticated canines did, however, all due to the presence of the knowing human and body language cues. The human wasn't pointing or actively trying to tell each test subject where the meat was, they were just sitting there motionless.
Body language is the single most important communication tool between dogs and humans. More so than verbal commands. And that didn't happen on accident; it was done with thousands of years of breeding and evolution.
A lot of people don't realize that the partnership between dogs and humans isn't replicated anywhere else on Earth and with any other pair of unrelated animals. It's the only case of two completely unrelated species actively seeking each other out for co-habitation. Dogs actually can't survive on their own. They've lost the natural ability to hunt in a pack, even though most still have a "prey" instinct. That instinct forces them to chase and even kill something, but it never actually crosses their minds to eat what they've killed. We've basically bred that right out of them.
jas
Years and generations passed, and the resulting camp wolves still looked very much like their non-camp brethren. But they'd began losing their ability to hunt. When we realized they could be advantageous to have around, we found the less aggressive versions and, for lack of a better word, adopted them into our camps. The meaner ones were probably shunned or even killed. This process repeated itself over many more years until the domesticated canine basically acted and looked nothing like its wolf predecessor.
The Eugenics experiment that is today's dog, more or less, got its kick in 18th century Europe. There, with leisure time available to many, "customizing" the dog to look and act in specific ways became a hobby, and then an industry. And it's been with us ever since.
Another interesting and related test has been done where a piece of meat was hidden under one of 2 paper cups. A human was sitting behind the cups and would know which cup the meat was hidden under. Wolves and dogs were then given a chance to find it. It's understood that a wolf's nose is substantially better tuned than a domesticated canine's is, so they should have had a nearly 100% success rate. They didn't. The domesticated canines did, however, all due to the presence of the knowing human and body language cues. The human wasn't pointing or actively trying to tell each test subject where the meat was, they were just sitting there motionless.
Body language is the single most important communication tool between dogs and humans. More so than verbal commands. And that didn't happen on accident; it was done with thousands of years of breeding and evolution.
A lot of people don't realize that the partnership between dogs and humans isn't replicated anywhere else on Earth and with any other pair of unrelated animals. It's the only case of two completely unrelated species actively seeking each other out for co-habitation. Dogs actually can't survive on their own. They've lost the natural ability to hunt in a pack, even though most still have a "prey" instinct. That instinct forces them to chase and even kill something, but it never actually crosses their minds to eat what they've killed. We've basically bred that right out of them.
jas
They're an alien species, marooned on earth. They are patiently waiting for us to learn how to travel to the stars so that they can hitch a ride back home. In the meantime they are leading life of leisure. Oh, wait - that would be cats... never mind. 😉
Seriously #1 ... the dog as alien theme was the plot of an old SF short story I read last year. It was written well enough, that I actually considered - jut for a moment - whether it was possible.
Seriously #2 ... keep in mind that there were domesticated dogs on the north west coast of North America, before contact with Europeans. For the most part these dogs were breed and used as a source of weaving fibre. Wolves hanging about camps may be the preferred theory for European dogs, it may not account for First Nation dogs.
We live in an interesting world, eh?
jasonvp
macrumors 6502a
Um. Nothing in what you wrote disqualifies the camp wolf theory for the aforementioned canines. At all, really. If it worked in Africa and Europe, there's no reason why it wouldn't have also worked that way in the Americas. It just means the final product (dog as companion vs dog as fiber provider) is a bit different.
jas
Oh, I know that dogs might have been domesticated in a similar way on the west coast, but... there is a difference as well. Communities here tended to rotate among their seasonal camps by canoe. It would have been difficult to maintain a continuous link to any particular wolf population. But I believe the range of the role of dogs on the west coast was also very limited, so that could be a result of non-continuous contact.
My point was simply to note that to take a euro-centric model for domestication and then apply it globally probably isn't entirely accurate. Earlier someone noted that this process was probably happening independently in several locations... which I agree with. I also think it happened in different ways in different places. I think this makes the whole idea of domesticating wolves that much more interesting.
It means it wasn't just a fluke thing that happened with one community of humans and one community of wolves, but that there was something in the genetic makeup of wolves globally that made enough individuals conducive to being domesticated. Which raises another question.... are all wolves ready to be domesticated - and the existing population of wild wolves were simply not in contact with humans at that point in time. Or, was there a sub-species of wolves that were more domesticable - in essence a 'fork' in the genome?
A number of years ago I read that in fact there were two species (or perhaps sub-species) of beavers in North America. One was nocturnal and other came out during the day. We trapped into extinction all the daytime beavers, leaving the nocturnal version - which we are taught were the only type of beavers.
Perhaps there were two kinds of wolves? One that liked humans, and one that didn't. We domesticated the first kind, leaving the second. This would mean that if we tried to domestic (as an experiment) wolves from this second group we would have very different results. Just idle speculation...