Thread: Origin and of Dogs

Alright so I read two studies on the origin(s) of dogs.

One study, from 1997, concludes that dogs "originated more than 100,000 years before the present" and that the results also indicate "episodes of admixture between wolves and dogs". This converges with archaeological evidence suggesting that wolves associated with humans at least as far back as 100,000 years ago.

http://web.archive.org/web/200709262...dog/wayne1.htm


The second study, from 2002, concludes that dogs "evolved from just a handful of wolves tamed by humans living in or near China less than 15,000 years ago". This handful of wolves including "three original founding females" which the mitochondrial DNA is from.

http://news.bbc.co.uk/2/hi/science/nature/2498669.stm


What I want to understand is why do these two studies differ in their dates? Was it their sample sizes, a priori assumptions, experimental errors, or some problem with the molecular clock that I'm not aware of or don't understand.

I see no contradiction

Originally Posted by granpa

I see no contradiction

One says dogs originated more than 100,000yrs ago, another says they originated less than 15,000yrs ago.

I've never been a big fan of molecular clocks, it seems they can vary quite a bit depending on the organism or the weather conditions. Whereas other dating techniqes are fairly reliable and we know when they don't work (eg carbon dating for marine organisms). But it would be nice to hear from someone who thinks it's more reliable. On the other hand the origins of dogs is fairly recent, and a difference of 85,000 years seems like a lot, but it wouldn't be such a bad error when looking at something 100 million years old (but then measuring that far back might add up the errors further).

Less likely that dogs/wolves were domesticated as a sudden capture from the wild, as with pigs or chickens, than that some wolf populations self-domesticated by scavanging in the tracks of human hunters. Their physical and social adaptation would develop slowly and fitfully.

The behaviours of begging food, fetching sticks (thrown weapons), tail wagging, and barking at predatory wolves, I imagine developed before these animals ever got within arms's reach of humans. Would we call them dogs or wolves then?

I'm not doubting that all dogs can be genetically traced to three individuals less than 15,000 y.o. However I'm sure no one at the time would have seen these as a different animal.

the fact that all dog mitochondrial dna came from a few individuals from 15000 yrs ago doesnt imply that dogs as a group evolved at that time.

fact:

There are no two studies. One is a news report.

To do:
Look up the article behind the news report and say what they say about the older studies.

Prediction:
Relevant answer is given in the discussion section of paper.

Question:
Who can be arsed to look up the original paper?

Recent studies on breeding silver foxes for tameness show that some of the attributes of dogs arise after a few generations of breeding.
http://www.suite101.com/content/dome...ver-fox-a68305

I quote :

"As the experiment continued, something else began to happen. By generations eight and ten, the foxes started developing spots. Some of them were even marked like border collies. Some foxes developed shorter legs and tails than the wild type, while others had tails that curled over their backs. Even more unusually, a few vixens had estrus cycles longer than normal, and a few also had estrus cycles twice a year. All of these traits are traits of domestic animals.

Selection of Tameness Alone Yielded These Changes"


This makes it probable that wolves were domesticated as wolves, and bred for tameness, after which they took on the attributes of dogs.

This may help to explain the apparent discrepancy:

From the quantitative data on haplotype similarity, Vilà et al also proposed a new date for the first domestication of the dog. The first archaeological evidence of morphologically modern dog remains found in association with human remains is from 14000 years ago. On the other hand, palaeontological evidence shows that wolves and coyotes were separated about 1 million years ago. Since wolves and coyotes show a minimum 20-base divergence, we can estimate that divergence grows at a rate of about 1 substitution per 50,000 years. If all the dogs whose haplotypes are found in the large clade derive from a single parental line, we would expect that the 2.6-base divergence within that clade would have taken 130,000 years to emerge. Vilà et al therefore propose that the initial domestication of dogs occurred around 130,000 years ago, with some other event about 15,000 years ago leading to morphological change within the domestic dog population.

http://en.wikipedia.org/wiki/Talk:Or...e_domestic_dog

Originally Posted by spuriousmonkey

fact:

There are no two studies. One is a news report.

To do:
Look up the article behind the news report and say what they say about the older studies.

Prediction:
Relevant answer is given in the discussion section of paper.

Question:
Who can be arsed to look up the original paper?

I've already tried looking up the original study, and maybe it's the words I'm entering into the search, but I can't seem to find it.

...initial domestication of dogs occurred around 130,000 years ago, with some other event about 15,000 years ago leading to morphological change within the domestic dog population.]

That's where I'm confused because the second source instead is implying that dogs originated 15,000 years ago from wolves in China rather than saying, dogs became morphologically distinct from wolves in China 15,000 years ago.

The news report one though is speaking of mitochondrial "Eves" which tend to be far more recent than when the species diverged. I'm not confident enough in my knowledge of evolutionary biology to take a swing at challenging either studies.

Not sure if this will help but this guy (AronRa) posted two videos explaining the canine family and the feline family trees. It is very in depth and through and VERY informative. Though he goes on to stat that creationists are making wrongful assumptions on things and proves why. I highly recommend you check this out if you are looking into those two things.

Felines:
http://www.youtube.com/watch?v=pNrt9...eature=related

Canine:
http://www.youtube.com/watch?v=bJ-Da...eature=related

Originally Posted by i_feel_tiredsleepy

The news report one though is speaking of mitochondrial "Eves" which tend to be far more recent than when the species diverged. I'm not confident enough in my knowledge of evolutionary biology to take a swing at challenging either studies.

That seems really obvious to me now, why didn't I think of that earlier? Also looking back now at the other comments, I realize that this probably is the same thing granpa meant by his comment.


While I'm posting, does anyone have any idea why my quotes never work? I'm not even coding them myself, I've been lazy and just clicked the quote button at the bottom right of a user's comment.

Originally Posted by Erebus

While I'm posting, does anyone have any idea why my quotes never work? I'm not even coding them myself, I've been lazy and just clicked the quote button at the bottom right of a user's comment.

It is your post count. Certain features are turned off for new members, in order to foil spammers.

probable that wolves were domesticated as wolves, and bred for tameness...

Vilà et al therefore propose that the initial domestication of dogs occurred around 130,000 years ago

I disagree with the above assumtion that wolves were either "domestic" or not, as an event we can date. I argue that wolf populations in contact (direct competition) with humans began adapting to coexist with us long before breeding or any sort of "domestication occured".

Nothing special about humans that prevents other species from adapting to us. Therefore wolves must have adapted to human competition.

Moreover, I suggest that humans did not domesticate (meaning: handle them, feed them, breed them) dogs until they had aquired most traits differentiating dogs from their hostile cousins.

in other words, humans didnt try to tame dogs until they became domesticated first

Yes, we didn't domesticate them until they'd adapted to friendly coexistence, in contrast to wolves.

When humans hunted mammoth, the rewards for friendly coexistance would be great.

You can also look at how we've applied selective pressure against animals that threaten or annoy us, since at least the time we began to throw rocks with accuracy. Why are there no big cats left in Europe? Because not one population of them adapted such that humans would tolerate them.

Domestication of wolves probably began with human adoption of wolf cubs. This sort of thing is very human and happens today - all the time. A person, usually a woman, see a young wild animal, and thinks it is cute. Then takes it home and feeds it. Usually, this exercise does not do much good, but occasionally the wild animal responds positively to human care and thrives.

It is possible that, over a period of thousands of years, the adoption of wolf cubs happened many, many times. All it needs is one true success.

My earlier post on experiments of the taming of the silver fox shows how the initial changes in wolves would have happened. If a wolf cub grows up vicious, someone will kill it. I suspect the woman will try to save it, but males are less nurturing and more callous. If all the nasty wolves are killed over a period of many generations, then the population of domestic wolves will change just as the silver foxes in http://www.suite101.com/content/dome...ver-fox-a68305

Plainly Skeptic we propose antithetical scenarios.


1) Would you agree the human species (like any species) has always applied selective pressures to other species, "in the wild" so to speak?

2) Would you agree the activity of humans (e.g. hunting megafauna) would attract the interest of wolves? Wolves and humans encountered each other frequently or even routinely, yes?

3) If both true, why would humans and wolves *not* adapt to coexist, where their ranges and food sources overlapped?


I think you forgot that we too were part of the environment animals adapted to.

Pong

I will try to answer your queries.

1. Have we applied selective pressure on wild animals?
Of course we have. But not in such a way as to lead them to become tamer. Quite the reverse. Human action tends to create wariness. Since we hunt and kill, the animals we target evolve to become shyer, not tamer.

2. Human activity attracting wolves?
No. Quite the reverse. While I have no idea how humans and wolves interacted 10,000 plus years ago, we know exactly what happened in the last few hundred. Humans distrusted wolves, and feared them. This leads to action that is antagonistic. Wolves today, and in recent history are shy of human contact. Not attracted. Coyotes and bears hang around human settlements for food scraps. Wolves do not.

3. Adapt to coexist?
Again, no. Humans tend to kill competitors.

There is a pre-adaptation, of course, with respect to wolves. Wolves are pack animals, and follow a pack leader. Thus, if a human adopts a wolf cub and raises it, it should accept that human as its pack leader. This permits the wolf to be trained, and permits cooperation.

Pong, I suggest you read the silver fox reference I posted. The breeding for tameness in silver foxes created, as a side effect, the breeding of physical features characteristic of dogs. If it happens to silver foxes, it probably also happened with wolves. But how could wolves be bred for tameness if they simply co-adapt as wild animals, as your theory suggests?

My theory takes into account human nature. Human females are prone to adopting 'cute' young wild animals. Since we know that this happens today, it probably happened thousands of years ago also.

Thanks. Now I'll bring conflicting evidence to your answers.

Originally Posted by skeptic

1. Have we applied selective pressure on wild animals?
Of course we have. But not in such a way as to lead them to become tamer. Quite the reverse...

Observe the animals in city parks: the pigeons, squirrels, ducks, crows, etc. These are not "domestic" animals. We certainly don't breed them. Without exception though, they're "tame" in that they're non-hostile to humans. If an individual does show hostile behaviour, its career will be short. The same is true of animals encountered in a rural setting - the bear that scavenge near a highway, or the deer that get into your garden for examples. Our selective pressure has both rewarded *wild* animals for behaviour we tolerate or appreciate, and punished *wild* animals for behaviour we dislike.

In the context of wolves, this selection by humans for "tameness" means wolves don't regard us as enemies to be driven off, or prey to be eaten. We've selected wolves to view humans as exceptional; they know man and avoid him.

Originally Posted by skeptic

2. Human activity attracting wolves?
No. Quite the reverse. While I have no idea how humans and wolves interacted 10,000 plus years ago, we know exactly what happened in the last few hundred. Humans distrusted wolves, and feared them. This leads to action that is antagonistic. Wolves today, and in recent history are shy of human contact. Not attracted. Coyotes and bears hang around human settlements for food scraps. Wolves do not.

This is a problem for wolves, because we and they have shared the same career: following herds. Both species dabbled in scavenging carcases and head-on predation of these herds. But probably both species focused mainly on weak or isolated individuals. Wolves and humans would be in very close competition. For illustration: humans would be smart to find out what the wolves are howling over, as wolves would be smart to follow up on human movements. This could make the difference between a fresh carcass to scavenge, and starvation.

So isn't it puzzling that wolves today *never* hang around humans hoping for a bone, while dogs do exactly that even now.

Originally Posted by skeptic

3. Adapt to coexist?
Again, no. Humans tend to kill competitors.

Right, we select against behaviours that harm or annoy us. We (violently) select against those wolves that harm or annoy us.

Suppose that certain wolf packs (breeds) tended to scavenge our leavings, rather than compete with us directly. They could make a pretty good career of learning to track human hunters at safe distance, for the regular supply of carcases we left, yes? Can you imagine that these particular wolf packs would defend their food from other wolves? Can you see how they'd begin to speciate from the general wolf population, and adapt further into their human-dependent niche?

Meanwhile the *other* wolves, being excluded from the niche, would better adapt to avoid humans altogether.

Originally Posted by skeptic

Pong, I suggest you read the silver fox reference I posted. The breeding for tameness in silver foxes created, as a side effect, the breeding of physical features characteristic of dogs. If it happens to silver foxes, it probably also happened with wolves. But how could wolves be bred for tameness if they simply co-adapt as wild animals, as your theory suggests?

I read it already, but thanks for the very relevent reference. We should keep in mind that "breeding for tameness" in that experiment meant breeding foxes that don't bite people. The condition was not-biting, which is not the same as friendly behaviour. The intriguing result was that selecting this one trait of *not-biting* roped in a bunch of doggie traits like active friendliness towards humans (as opposed to passivity), and markings we associate with dogs.

Since no one understands the mechanism behind those weird results (and the experiment hasn't been repeated :? ) I won't speculate upon it.

We can however consider a niche of wolves that learned to scavenge after human hunters. We can guess how they'd continue to adapt to that career, and how humans might adapt to them. It seems to me that all the traits setting dogs apart from wolves would enhance that career. They follow people around, sniffing for bones especially. They have markings (like the upright, wagging tail) that signal they are not a threat to us. I think that these breeds of wolf would grow more tolerated by humans, as they evolved uniquely "dog" behaviours and markings. They'd be a great help in alerting us to hostile wolf packs, or even fighting those off. Gradually we'd trust these specializing wolves within a stone's throw, then arm's reach... finally fireside and what you'd call "domestic".

So that is how we select for tameness, without forcibly controlling which individuals mate.

It could also be said that *they* selected *us* for tameness - meaning humans who got along with dogs were more likely to be successful hunters. Again, it isn't necessary one species dictates the mating of the other.

Pong

I think the time factor may be a bit of a red herring here. Wolf domestication happened a long time ago. Certainly during the hunter/gatherer tribal period of human existence. If we are going to speculate about human behaviour leading to wolf domestication, we should look at behaviour then rather than behaviour now.

Maternal nurturing behaviour would be exactly the same then as now. Tolerance to animals would depend on current needs. At that stage, there is no way that pigeons etc could have become acclimated to human presence. Get too close and bang - into the barbeque. The fact that modern over-fed humans are tolerant of, and encourage, tamer wild animals does not mean that happened way back then.

If you think of human behaviour back in hunter/gatherer days, you have several possible approaches to animals - mostly hostile. They might be edible, like pigeons, and killed for food. They might be a danger, like bears. In that case they would be chased off by group action. Even a bear will not stay still with 50 ugly big cavemen after it. Or they might be killed because they are a perceived threat to young children - like wolves. Only a non threat, like a wolf cub, would be tolerated.

I cannot see any such tribe tolerating a wolf pack that follows to glean human leavings. Wolves may not be a big threat to adults, but they will grab a young child if they can. As such, they are enemies. And enemies are killed.

On the silver fox thing...
The reference I posted is not the full story. There was a more extensive story in New Scientist, but I lost the actual reference there. The research also covered breeding rats. They bred one group for tameness, and got rats that would nuzzle up to a human without being trained to be tame. They also bred them for aggression, and got a population of rats that would attack on sight, with no provocation.

The point is that, when humans take over and control the breeding of a wild animal, they can achieve tameness within a few generations. If our hypothetical hunter/gatherer woman adopts wolf cubs, that breeding would happen pretty damn quickly. The men of the tribe would not tolerate any that grew into an animal that would bite. Such growing and aggressive wolves would receive a bash over the head quick smart. A few generations later, and we have tame wolves/dogs.

I think both theories make some sense. Pong's makes slightly more sense, though, because humans don't eat the bones. The nature of a wolf pack is that the dominant wolf eats first, then passes the carcass on to the next most dominant, who eats and passes it on again...... etc.

So, every time we hunt, we eat everything else we want, then we leave the bones behind for the wolves to eat, essentially playing the same role as the dominant wolf plays in their pack. They might start to think we actually are in a pack with them.

kojax

I disagree.
Why? Because observations suggest a pattern.
Nowhere in the world do we see a human tribe in a relationship with a wild animal such as Pong suggests. It just does not happen. The most that is likely to happen is that a scavenger raids human leavings, and runs, before the people there kill it. Which they will do, given a chance. Evolving to become tamer in that situation is most definitely contrary to survival.

Even in India, where certain animals are 'sacred' and tolerated for religious reasons, those animals do not become tame. Go to an Indian temple where rats or monkeys have been tolerated for a very long time, and watch yourself. Get familiar with those wild animals and you get bitten - badly.

Wolves are predators. They hunt and kill to eat. That includes a human baby or infant if they get the chance. No way is tolerance going to evolve.

On the other hand, humans adopting wild animals young is common.

Originally Posted by skeptic

kojax

I disagree.
Why? Because observations suggest a pattern.
Nowhere in the world do we see a human tribe in a relationship with a wild animal such as Pong suggests. It just does not happen. The most that is likely to happen is that a scavenger raids human leavings, and runs, before the people there kill it. Which they will do, given a chance. Evolving to become tamer in that situation is most definitely contrary to survival.

What if the humans deliberately left their bones for them, and refrained from attacking them most of the time?

Just think about what happens in nature when people feed pigeons or seagulls. At first, the animals merely supplement their diet with the bread crumbs, but if they start getting enough of them, then they stop hunting altogether, and soon forget how.

Kojax

Why? Why would humans feed wild wolves? And do it over a long enough period for those wolves to evolve?

Makes no sense to me.

However, imagine a woman or girl taken to a pet shop, where there are German Shepherd puppies, which look very like wolf cubs. Imagine the comment : "Oh they are so cute. I want them!"

All I am suggesting is that something which happens today, very frequently, also happened thousands of years ago. The rest is a simple consequence of the original adoption.

could have been raised for their pelts I guess.
seems improbably though.

Originally Posted by skeptic

Kojax

Why? Why would humans feed wild wolves? And do it over a long enough period for those wolves to evolve?

Makes no sense to me.

For the time element, just look at the pigeons and seagulls. There's no lengthy evolution involved. As far as I know, the seagulls who become dependent are totally wild to start. They lose self sufficiency in a single lifetime. On the other hand, domestic cats never lose the ability to hunt no matter how well you feed them, so I guess it's just luck of the draw which way an animal's genome will treat that issue. Maybe dogs lost the coin toss?

As for their usefulness, the dogs would have been valuable from the start because they bark whenever a potential rival enters their territory, making them useful as an alarm system against predators or rival tribes, as long as they have the common sense not to attack the humans themselves.

kojax

Yes. But that is still speculation. As far as I know, there is no incidence in recent times where a wild wolf pack has made itself useful in that way. Nor does it seem likely that humans would become tolerant of the near presense of wild animals that are capable of grabbing and eating a baby or infant. If a wolf pack hung around a human tribe, it is far more likely that the people involved would do their best to kill any and all wolves they could get close to.

My theory, though, is based on known behaviour. We already know that adopting pups is something that people do - often with great enthusiasm - and we know that breeding captive silver foxes for tameness, as we would expect in adopted wolves, leads to dog-like characteristics. So my idea is based on known facts, while yours is based on speculation, including some very unlikely ideas.

From what I understand, only a handful of animals have ever been domesticated due to a specific genetic characteristic; the fear of humans must be turned off. The genes associated with fear (wildness) are open to manipulation in these species. In general, this is not good for individual animals: chickens, sheep, cattle get eaten. Dogs too in some cultures! However, dogs are similar to us in being social and adaptable, predators not prey, and these, along with the protector-companion-hunting factor made them more valuable as partners than as food.

Wolves cannot be domesticated: even when hand-raised they go wild at 4-5 months. It seems likely that a change had to occur in a small group of wolves, which when obtained as pups and hand-raised, allowed the fear of humans to be switched off.

Perhaps this coincides with the 100,000 vs. 15,000 discrepancy. Dogs began differentiating from wolves some 100,000+ years ago, but were not genetically "tameable" (loss of fear) until much later - 15,000 y.a.

dexadog

That is not totally true.

For example : cattle were domesticated from the old aurochs. While aurochs are now extinct, records remain. It was also considered 'untameable'. Yet it was tamed.

The silver fox was similarly considered untameable. Wild black rats are not normally considered particularly tameable either. Yet a strain has been bred that will rub itself against humans and curl up in someone's lap.

I doubt there is any type of wild animal that is truly untameable.

The examples you mention are not domesticated.

dexa

The silver fox and the black rat I mentioned were subjects of a domestication experiment. I posted the reference earlier in this thread.

A Russian, Belyaev, tamed silver foxes and rats by breeding. Here is another reference.
http://en.wikipedia.org/wiki/Domesticated_silver_fox

You can see it on video at :
http://www.youtube.com/watch?v=oDb27ZP9zEE
The commentator of this video specifically says this illustrates how the wolf could have been tamed and physically modified, as I have been arguing.

Another reference :
http://www.theapricity.com/forum/showthread.php?t=18019

I quote from this reference
"On an animal-breeding farm in Siberia are cages housing two colonies of rats. In one colony, the rats have been bred for tameness in the hope of mimicking the mysterious process by which Neolithic farmers first domesticated an animal still kept today. When a visitor enters the room where the tame rats are kept, they poke their snouts through the bars to be petted.

The other colony of rats has been bred from exactly the same stock, but for aggressiveness instead. These animals are ferocious. When a visitor appears, the rats hurl themselves screaming toward their bars.

“Imagine the most evil supervillain and the nicest, sweetest cartoon animal, and that’s what these two strains of rat are like,” said Tecumseh Fitch, an animal behavior expert at the University of St. Andrews in Scotland"

Originally Posted by skeptic

kojax

Yes. But that is still speculation. As far as I know, there is no incidence in recent times where a wild wolf pack has made itself useful in that way. Nor does it seem likely that humans would become tolerant of the near presense of wild animals that are capable of grabbing and eating a baby or infant. If a wolf pack hung around a human tribe, it is far more likely that the people involved would do their best to kill any and all wolves they could get close to.

When we're talking about evolution, there is a long time for such a thing to emerge. What I've been told about keeping wolves as pets (this is purely anecdotal) is that the key to keeping them is to adhere to the rules of their society. If you are the master, then you must behave like their alphas do at all times, never, ever, let the wolf walk through a door before you, or it will immediately challenge you for supremacy. - Stuff like that.

Maybe what we need to look for is a human tribe that behaved like wolves, instead of a wolf pack that behaved like humans?

Originally Posted by dexadog

From what I understand, only a handful of animals have ever been domesticated due to a specific genetic characteristic; the fear of humans must be turned off. The genes associated with fear (wildness) are open to manipulation in these species. In general, this is not good for individual animals: chickens, sheep, cattle get eaten. Dogs too in some cultures!

.

It would be really funny if it turned out that we'd bred them first for food, and then kept them as pets.