2808. On the Origins of Dogs: The First Domesticated Animal

By Ed Yong, The Atlantic, June 2, 2016

Tens of thousands of years ago, before the internet, before the Industrial Revolution, before literature and mathematics, bronze and iron, before the advent of agriculture, early humans formed an unlikely partnership with another animal—the grey wolf. The fates of our two species became braided together. The wolves changed in body and temperament. Their skulls, teeth, and paws shrank. Their ears flopped. They gained a docile disposition, becoming both less frightening and less fearful. They learned to read the complex expressions that ripple across human faces. They turned into dogs.

Today, dogs are such familiar parts of our lives—our reputed best friends and subject of many a meme—that it’s easy to take them, and what they represent, for granted. Dogs were the first domesticated animals, and their barks heralded the Anthropocene. We raised puppies well before we raised kittens or chickens; before we herded cows, goats, pigs, and sheep; before we planted rice, wheat, barley, and corn; before we remade the world.

“Remove domestication from the human species, and there’s probably a couple of million of us on the planet, max,” says archaeologist and geneticist Greger Larson. “Instead, what do we have? Seven billion people, climate change, travel, innovation and everything. Domestication has influenced the entire earth. And dogs were the first.” For most of human history, “we’re not dissimilar to any other wild primate. We’re manipulating our environments, but not on a scale bigger than, say, a herd of African elephants. And then, we go into partnership with this group of wolves. They altered our relationship with the natural world.”

Larson wants to pin down their origins. He wants to know when, where, and how they were domesticated from wolves. But after decades of dogged effort, he and his fellow scientists are still arguing about the answers. They agree that all dogs, from low-slung corgis to towering mastiffs, are the tame descendants of wild ancestral wolves. But everything else is up for grabs.

Some say wolves were domesticated around 10,000 years ago, while others say 30,000. Some claim it happened in Europe, others in the Middle East, or East Asia. Some think early human hunter-gatherers actively tamed and bred wolves. Others say wolves domesticated themselves, by scavenging the carcasses left by human hunters, or loitering around campfires, growing tamer with each generation until they became permanent companions.

Dogs were domesticated so long ago, and have cross-bred so often with wolves and each other, that their genes are like “a completely homogenous bowl of soup,” Larson tells me, in his office at the University of Oxford. “Somebody goes: what ingredients were added, in what proportion and in what order, to make that soup?” He shrugs his shoulders. “The patterns we see could have been created by 17 different narrative scenarios, and we have no way of discriminating between them.”

The only way of doing so is to look into the past. Larson, who is fast-talking, eminently likable, and grounded in both archaeology and genetics, has been gathering fossils and collaborators in an attempt to yank the DNA out of as many dog and wolf fossils as he can. Those sequences will show exactly how the ancient canines relate to each other and to modern pooches. They’re the field’s best hope for getting firm answers to questions that have hounded them for decades.

And already, they have yielded a surprising discovery that could radically reframe the debate around dog domestication, so that the big question is no longer when it happened, or where, but how many times.

*    *   *

On the eastern edge of Ireland lies Newgrange, a 4,800-year-old monument that predates Stonehenge and the pyramids of Giza. Beneath its large circular mound and within its underground chambers lie many fragments of animal bones. And among those fragments, Dan Bradley from Trinity College Dublin found the petrous bone of a dog.

Press your finger behind your ear. That’s the petrous. It’s a bulbous knob of very dense bone that’s exceptionally good at preserving DNA. If you try to pull DNA out of a fossil, most of it will come from contaminating microbes and just a few percent will come from the bone’s actual owner. But if you’ve got a petrous bone, that proportion can be as high as 80 percent. And indeed, Bradley found DNA galore within the bone, enough to sequence the full genome of the long-dead dog.

Larson and his colleague Laurent Frantz then compared the Newgrange sequences with those of almost 700 modern dogs, and built a family tree that revealed the relationships between these individuals. To their surprise, that tree had an obvious fork in its trunk—a deep divide between two doggie dynasties. One includes all the dogs from eastern Eurasia, such as Shar Peis and Tibetan mastiffs. The other includes all the western Eurasian breeds, and the Newgrange dog.

The genomes of the dogs from the western branch suggest that they went through a population bottleneck—a dramatic dwindling of numbers. Larson interprets this as evidence of a long migration. He thinks that the two dog lineages began as a single population in the east, before one branch broke off and headed west. This supports the idea that dogs were domesticated somewhere in China.

But there’s a critical twist.

The team calculated that the two dog dynasties split from each other between 6,400 and 14,000 years ago.  But the oldest dog fossils in both western and eastern Eurasia are older than that. Which means that when those eastern dogs migrated west into Europe, there were already dogs there.

To Larson, these details only make sense if dogs were domesticated twice.

Here’s the full story, as he sees it. Many thousands of years ago, somewhere in western Eurasia, humans domesticated grey wolves. The same thing happened independently, far away in the east. So, at this time, there were two distinct and geographically separated groups of dogs. Let’s call them Ancient Western and Ancient Eastern. Around the Bronze Age, some of the Ancient Eastern dogs migrated westward alongside their human partners, separating from their homebound peers and creating the deep split in Larson’s tree. Along their travels, these migrants encountered the indigenous Ancient Western dogs, mated with them (doggy style, presumably), and effectively replaced them.

Today’s eastern dogs are the descendants of the Ancient Eastern ones. But today’s western dogs (and the Newgrange one) trace most of their ancestry to the Ancient Eastern migrants. Less than 10 percent comes from the Ancient Western dogs, which have since gone extinct.

This is a bold story for Larson to endorse, not least because he himself has come down hard on other papers suggesting that cows, sheep, or other species were domesticated twice. “Any claims for more than one need to be substantially backed up by a lot of evidence,” he says. “Pigs were clearly domesticated in Anatolia and in East Asia. Everything else is once.” Well, except maybe dogs.

Other canine genetics experts think that Larson’s barking up the wrong tree. “I’m somewhat underwhelmed, since it’s based on a single specimen,” says Bob Wayne from the University of California, Los Angeles. He buys that there’s a deep genetic division between modern dogs. But, it’s still possible that dogs were domesticated just once, creating a large, widespread, interbreeding population that only later resolved into two distinct lineages.

In 2013, Wayne’s team compared the mitochondrial genomes (small rings of DNA that sit outside the main set) of 126 modern dogs and wolves, and 18 fossils. They concluded that dogs were domesticated somewhere in Europe or western Siberia, between 18,800 and 32,100 years ago. And genes aside, “the density of fossils from Europe tells us something,” says Wayne. “There are many things that look like dogs, and nothing quite like that in east Asia.”

Peter Savolainen from the KTH Royal Institute of Technology in Stockholm disagrees. By comparing the full genomes of 58 modern wolves and dogs, his team has shown that dogs in southern China are the most genetically diverse in the world. They must have originated there around 33,000 years ago, he says, before a subset of them migrated west 18,000 years later.

That’s essentially the same story that Larson is telling. The key difference is that Savolainen doesn’t buy the existence of an independently domesticated group of western dogs. “That’s stretching the data very much,” he says. Those Ancient Western dogs might have just been wolves, he says. Or perhaps they were an even earlier group of migrants from the east. “I think the picture must seem a bit chaotic,” he says understatedly. “But for me, it’s pretty clear. It must have happened in southern East Asia. You can’t interpret it any other way.”

Except, you totally can. Wayne does (“I’m certainly less dogmatic than Peter,” he says). Adam Boyko from Cornell University does, too: after studying the genes of village dogs—free-ranging mutts that live near human settlements—he argued for a single domestication in Central Asia, somewhere near India or Nepal. And clearly, Larson does as well.

Larson adds that his gene-focused peers are ignoring one crucial line of evidence—bones. If dogs originated just once, there should be a neat gradient of fossils with the oldest ones at the center of domestication and the youngest ones far away from it. That’s not what we have. Instead, archaeologists have found 15,000-year-old dog fossils in western Europe, 12,500-year-old ones in east Asia, and nothing older than 8,000 years in between.

“If we’re wrong, then how on earth do you explain the archaeological data?” says Larson. “Did dogs jump from East Asia to Western Europe in a week, and then go all the way back 4,000 years later?” No. A dual domestication makes more sense. Mietje Genompré, an archaeologist from the Royal Belgian Institute of Natural Sciences, agrees that the bones support Larson’s idea. “For me, it’s very convincing,” she says.

But even Larson is hedging his bets. When I ask him how strong his evidence is, he says, “Like, put a number on it? If was being bold, I’d say it’s a 7 out of 10. We lack the smoking gun.”

Why is this so hard? Of all the problems that scientists struggle with, why has the origin of dogs been such a bitch to solve?

For starters, the timing is hard to pin down because no one knows exactly how fast dog genomes change. That pace—the mutation rate—underpins a lot of genetic studies. It allows scientists to compare modern dogs and ask: How long ago must these lineages have diverged in order to build up this many differences in their genes? And since individual teams use mutation rate estimates that are wildly different, it’s no wonder they’ve arrived at conflicting answers.

Regardless of the exact date, it’s clear that over thousands of years, dogs have mated with each other, cross-bred with wolves, travelled over the world, and been deliberately bred by humans. The resulting ebb and flow of genes has turned their history into a muddy, turbid mess—the homogeneous soup that Larson envisages.

Wolves provide no clarity. Grey wolves used to live across the entire Northern Hemisphere, so they could have potentially been domesticated anywhere within that vast range (although North America is certainly out). What’s more, genetic studies tell us that no living group of wolves is more closely related to dogs than any other, which means that the wolves that originally gave rise to dogs are now extinct. Sequencing living wolves and dogs will never truly reveal their shrouded past; it’d be, as Larson says, like trying to solve a crime when the culprit isn’t even on the list of suspects.

“The only way to know for sure is to go back in time,” he adds.

The study informally known as the Big Dog Project was born of frustration. Back in 2011, Larson was working hard on the origin of domestic pigs, and became annoyed that scientists studying dogs were getting less rigorous papers in more prestigious journals, simply because their subjects were that much more charismatic and media-friendly. So he called up his longstanding collaborator Keith Dobney. “Through gritted teeth, I said: We’re fucking doing dogs. And he said: I’m in.”

Right from the start, the duo realized that studying living dogs would never settle the great domestication debate. The only way to do that was to sequence ancient DNA from fossil dogs and wolves, throughout their range and at different points in history. While other scientists were studying the soup of dog genetics by tasting the finished product, Larson would reach back in time to taste it at every step of its creation, allowing him to definitively reconstruct the entire recipe.

In recent decades, scientists have become increasingly successful at extracting and sequencing strands of DNA from fossils. This ancient DNA has done wonders for our understanding of our own evolution. It showed, for example, how Europe was colonized 40,000 years ago by hunter-gatherers moving up from Africa, then 8,000 years ago by Middle Eastern farmers, and 5,000 years ago by horse-riding herders from the Russian steppes. “Everyone in Europe today is a blend of those three populations,” says Larson, who hopes to parse the dog genome in the same way, by slicing it into its constituent ingredients.

Larson originally envisaged a small project—just him and Dobney analyzing a few fossils. But he got more funding, collaborators, and samples than he expected. “It just kind of metastasized out of all proportion,” he says. He and his colleagues would travel the world, drilling into fossils and carting chips of bone back to Oxford. They went to museums and private collections. (“There was a guy up in York who had a ton of stuff in his garage.”) They grabbed bones from archaeological sites.

The pieces of bone come back to a facility in Oxford called the Palaeo-BARN—the Palaeogenomics and Bioarchaeology Research Network. When I toured the facility with Larson, we wore white overalls, surgical masks, oversoles, and purple gloves, to keep our DNA (and that of our skin microbes) away from the precious fossil samples. Larson called them ‘spacesuits.’ I was thinking ‘thrift-store ninja.’

In one room, the team shoves pieces of bone into a machine that pounds it with a small ball bearing, turning solid shards into fine powder. They then send the powder through a gauntlet of chemicals and filters to pull out the DNA and get rid of everything else. The result is a tiny drop of liquid that contains the genetic essence of a long-dead dog or wolf. Larson’s freezer contains 1,500 such drops, and many more are on the way. “It’s truly fantastic the kind of data that he has gathered,” says Savolainen.

True to his roots in archaeology, Larson isn’t ignoring the bones. His team photographed the skulls of some 7,000 prehistoric dogs and wolves at 220 angles each, and rebuilt them in virtual space. They can use a technique called geometric morphometrics to see how different features on the skulls have evolved over time.

The two lines of evidence—DNA and bones—should either support or refute the double domestication idea. It will also help to clear some confusion over a few peculiar fossils, such as a 36,000 year old skull from Goyet cave in Belgium. Genompré thinks it’s a primitive dog. “It falls outside the variability of wolves: it’s smaller and the snout is different,” she says. Others say it’s too dissimilar to modern dogs. Wayne has suggested that it represents an aborted attempt at domestication—a line of dogs that didn’t contribute to modern populations and is now extinct.

Maybe the Goyet hound was part of Larson’s hypothetical Ancient Western group, domesticated shortly after modern humans arrived in Europe. Maybe it represented yet another separate flirtation with domestication. All of these options are on the table, and Larson thinks he has the data to tell them apart. “We can start putting numbers on the difference between dogs and wolves,” he says. “We can say this is what all the wolves at this time period look like; does the Goyet material fall within that realm, or does it look like dogs from later on?”

Larson hopes to have the first big answers within six to twelve months. “I think it’ll clearly show that some things can’t be right, and will narrow down the number of hypotheses,” says Boyko. “It may narrow it down to one but I’m not holding my breath on that.” Wayne is more optimistic. “Ancient DNA will provide much more definitive data than we had in the past,” he says. “[Larson] convinced everyone of that. He’s a great diplomat.”

Indeed, beyond accumulating DNA and virtual skulls, Larson’s greatest skill is in gathering collaborators. In 2013, he rounded up as many dog researchers as he could and flew them to Aberdeen, so he could get them talking. “I won’t say there was no tension,” he says. “You go into a room with someone who has written something that sort of implies you aren’t doing very good science... there will be tension. But it went away very quickly. And, frankly: alcohol.”

“Everyone was like: You know what? If I’m completely wrong and I have to eat crow on this, I don’t give a shit. I just want to know.”

2734. Why Some Wolves Became Dogs?

By James Gorman, The New York Times, October 13, 2017

Photo: White Wolf Pack

NICOLET, Quebec — I’m sitting in an outdoor pen with four puppies chewing my fingers, biting my hat and hair, peeing all over me in their excitement.

At eight weeks old, they are two feet from nose to tail and must weigh seven or eight pounds. They growl and snap over possession of a much-chewed piece of deer skin. They lick my face like I’m a long-lost friend, or a newfound toy. They are just like dogs, but not quite. They are wolves.

When they are full-grown at around 100 pounds, their jaws will be strong enough to crack moose bones. But because these wolves have been around humans since they were blind, deaf and unable to stand, they will still allow people to be near them, to do veterinary exams, to scratch them behind the ears — if all goes well.

Yet even the humans who raised them must take precautions. If one of the people who has bottle-fed and mothered the wolves practically since birth is injured or feels sick, she won’t enter their pen to prevent a predatory reaction. No one will run to make one of these wolves chase him for fun. No one will pretend to chase the wolf. Every experienced wolf caretaker will stay alert. Because if there’s one thing all wolf and dog specialists I’ve talked to over the years agree on, it is this: No matter how you raise a wolf, you can’t turn it into a dog.

As close as wolf and dog are — some scientists classify them as the same species — there are differences. Physically, wolves’ jaws are more powerful. They breed only once a year, not twice, as dogs do. And behaviorally, wolf handlers say, their predatory instincts are easily triggered compared to those of dogs. They are more independent and possessive of food or other items. Much research suggests they take more care of their young. And they never get close to that Labrador retriever “I-love-all-humans” level of friendliness. As much as popular dog trainers and pet food makers promote the inner wolf in our dogs, they are not the same.The scientific consensus is that dogs evolved from some kind of extinct wolf 15,000 or more years ago. Most researchers now think that it wasn’t a case of snatching a pup from a den, but of some wolves spending more time around people to feed on the hunters’ leftovers. Gradually some of these wolves became less afraid of people, and they could get closer and eat more and have more puppies, which carried whatever DNA made the wolves less fearful. That repeated itself generation after generation until the wolves evolved to be, in nonscientific terms, friendly. Those were the first dogs.

People must spend 24 hours a day, seven days a week, for weeks on end with wolf puppies just to assure them that humans are tolerable. Dog puppies will quickly attach to any human within reach. Even street dogs that have had some contact with people at the right time may still be friendly.

Despite all the similarities, something is deeply different in dog genes, or in how and when those genes become active, and scientists are trying to determine exactly what it is.

There are clues.

Some recent research has suggested that dog friendliness may be the result of something similar to Williams syndrome, a genetic disorder in humans that causes hyper-sociability, among other symptoms. People with the syndrome seem friendly to everyone, without the usual limits.

Another idea being studied is whether a delay in development during a critical socializing period in a dog’s early life could make the difference. That delay might be discovered in the DNA, more likely in the sections that control when and how strongly genes become active, rather than in the genes themselves.

This is research at its very beginning, a long shot in some ways. But this past spring and summer, two scientists traveled to Quebec to monitor the development of six wolf pups, do behavior tests and take genetic samples. I followed them.

I visited other captive wolves as well, young and adult, to get a glimpse of how a research project begins — and, I confess, to get a chance to play with wolf puppies.

I wanted to have some firsthand experience of the animals I write about, to look wolves in the eye, so to speak. But only metaphorically. As I was emphatically told in a training session before going into an enclosure with adult wolves, the one thing you definitely do not do is look them in the eye.

Sleeping With Wolves

Zoo Académie is a combination zoo and training facility here on the southern bank of the St. Lawrence River, about two hours from Montreal. Jacinthe Bouchard, the owner, has trained domestic and wild animals, including wolves, all over the world.

This past spring she bred two litters of wolf pups from two female wolves and one male she had already at the zoo. Both mothers gave birth in the same den around the same time at the beginning of June. Then unusually bad flooding of the St. Lawrence threatened the den, so Ms. Bouchard had to remove them at about seven days old instead of the usual two weeks.

Then began the arduous process of socializing the pups. Ms. Bouchard and her assistant stayed day and night with the animals for the first few weeks, gradually decreasing the time spent with them after that.

On June 30, Kathryn Lord and Elinor Karlsson showed up with several colleagues, including Diane Genereux, a research scientist in Dr. Karlsson’s lab who would do most of the hands-on genetics work.

Dr. Lord is part of Dr. Karlsson’s team, which splits time between the University of Massachusetts Medical School in Worcester and the Broad Institute in Cambridge. Their work combines behavior and genetic studies of wolf and dog pups.

An evolutionary biologist, Dr. Lord is an old hand at wolf mothering. She has hand-raised five litters.

“You have to be with them 24/7. That means sleeping with them, feeding them every four hours on the bottle, ” Dr. Lord said.

Also, as Ms. Bouchard noted, “we don’t shower” in the early days, to let the pups get a clear sense of who they are smelling.

That’s very important, because both wolves and dogs go through a critical period as puppies when they explore the world and learn who their friends and family are.

With wolves, that time is thought to start at about two weeks, when the wolves are deaf and blind. Scent is everything.

In dogs, it starts at about four weeks, when they can see, smell and hear. Dr. Lord thinks this shift in development, allowing dogs to use all their senses, might be key to their greater ability to connect with human beings.

Perhaps with more senses in action, they are more able to generalize from tolerating individual humans with a specific scent to tolerating humans in general with a scent, sight and sound profile.

When the critical period ends, wolves, and to a lesser extent dogs, experience something like the onset of stranger anxiety in human babies, when people outside of the family suddenly become scary.

The odds of being able to pin down genetically the shift in this crucial stage are still long, but both Dr. Lord and Dr. Karlsson think the idea is worth pursuing, as did the Broad Institute. It provided a small grant from a program designed to support scientists who take leaps into the unknown — what you might call what-if research.

There are two questions the scientists want to explore. One, said Dr. Karlsson: ”How did a wolf that was living in the forest become a dog that was living in our homes?”

The other is whether fear and sociability in dogs are related to the same emotions and behaviors in humans. If so, learning about dogs could provide insights to some human conditions in which social interaction is affected, like autism, or Williams syndrome, or schizophrenia.

The pups at Zoo Académie were only three weeks old when the group of researchers arrived. I showed up the next morning and walked into a room strewn with mattresses, researchers and puppies.

The humans were still groggy from a night with little sleep. Pups at that age wake up every few hours to whine and paw any warm body within reach.

Wolf mothers prompt their pups to urinate and defecate by licking their abdomens. The human handlers massaged the pups for the same reason, but often the urination was unpredictable, so the main subject of conversation when I arrived was wolf pup pee. How much, on whom, from which puppy.

As soon as I walked in, I was handed a puppy to cradle and bottle-feed. The puppy was like a furry larva, persistent, single-minded, with an absolute intensity of purpose.

Even with fur, teeth and claws, the pups were still hungry and helpless, and I couldn’t help but remember holding my own children when they took a bottle. I suspect that tiger kittens and the young of wolverines are equally irresistible. It’s a mammal thing.

The first part of Dr. Lord’s testing was to confirm her observations that the critical period for wolves starts and ends earlier than that for dogs.

She set up a procedure for testing the pups by exposing them to something they could not possibly have encountered before — a jiggly buzzing contraption of bird-scare rods, a tripod and a baby’s mobile.

Each week she tested one pup, so that no pup got used to it. She would put the puppy in a small arena, with low barriers for walls and with the mobile turned on. She would hide, to avoid distracting the puppy. Video cameras recorded the action, showing how the pups stumbled and later walked around the strange object, or shied away from it, or went right up to sniff it.

At three weeks, the pups had been barely able to get around and were still sleeping almost every minute they weren’t nursing. By eight weeks, when I returned to have them gambol all over me, they were rambunctious and fully capable of exploration.

The researchers won’t publicize the results until observers who never saw the puppies view and analyze the videos. But Dr. Lord said that wolf experts considered eight-week-old wolf puppies past the critical period. They were so friendly to me and others because they had been successfully socialized already.

Before and after the test, she collected urine, to measure levels of a hormone called cortisol, which rises during times of stress. If the pup in the video would not approach the jiggly monster and cortisol levels were high, that would indicate that the pup had begun to experience a level of fear of new things that could stop exploration. That would confirm the timing of the critical period.

She and Dr. Karlsson and others from the lab also collected saliva for DNA testing. They planned to use a new technique called ATAC-seq that uses an enzyme to mark active genes. Then when the wolf DNA is fed into one of the advanced machines that map genomes, only the active genes would be on the map.

Dr. Genereux, who was isolating and then reading DNA, said she thought it was “a long shot” that they would find what they wanted. She and the other researchers plan to refine their techniques to ask the questions successfully.

When They Grow Up

And what are socialized wolves like when they grow up, once the mysterious genetic machinery of the dog and wolf direct them on their separate ways?

I also visited Wolf Park, in Battle Ground, Ind., a 65-acre zoo and research facility where Dana Drenzek, the manager, and Pat Goodmann, the senior animal curator, took me around and introduced me not only to puppies they were socializing, but to some adult wolves.

In the 1970s, Ms. Goodmann worked with Erich Klinghammer, the founder of Wolf Park, to develop the 24/7 model for socializing wolf puppies, exposing them to humans and then also to other wolves, so they could relate to their own kind but accept the presence and attentions of humans, even intrusive ones like veterinarians.

The sprawling outdoor baby pen was filled with cots and hammocks for the volunteers, since the wolves were now nine and 11 weeks old and living outdoors all the time. There were plastic and plywood hiding places for the wolves and plenty of toys. It looked like a toddlers’ playground, except for the remnants of their meals — the odd deer clavicle or shin bone, and other assorted ribs, legs and shoulder bones, sometimes with skin and meat still attached.

The puppies were extremely friendly with the volunteers they knew, and mildly friendly with me. The adult wolves I met were also courteous, but remote. Two older males, Wotan and Wolfgang, each licked me once and walked away. Timber, the mother of some of the pups, and tiny at 50 pounds, also investigated me and then retired to a platform nearby.

Only Renki, an older wolf who had suffered from bone cancer and now got around on three legs, let me scratch his head for a while. None was bothered by my presence. None was more than mildly interested. None seemed to realize or care about my own intense desire to see the wolves, be near them, learn about them, touch them.

I saw how powerfully a visit with wolves could affect how you feel about the animals. I wanted to come back and help raise pups, and keep visiting so that I could say an adult wolf knew me in some way.

But I also wondered whether it was right to keep wolves in this setting. In the wild, they travel large distances and kill their food. These wolves were all bred in captivity and that was never a possibility for them.

But was I simply indulging a fantasy of getting close to nature? Was this in the same category as wanting a selfie with a captive tiger? What was best for the wolves themselves?

I asked Ms. Goodmann about it. She said that park operated on the idea that getting to know the park’s wolves, which had never been deprived of an earlier life in the wild, would make visitors care more for wild wolves, for conservation, for preserving a life for wild carnivores that they could never be part of.

And she noted that Wolf Park operates as a combination zoo and research station. Students and others from around the world compete to work as interns, helping with everything from raising puppies to emptying the fly traps.

This is the rationale for all zoos, and it was a strong argument. Then she made it stronger. She pointed out that one of the interns, Doug Smith, worked on the reintroduction of wild wolves to Yellowstone National Park.

Dr. Smith has had a major role in the Wolf Restoration Project from the very beginning in 1995 and has been project leader since 1997. I reached him one morning at his office at park headquarters and asked him about his time as an intern at Wolf Park.

“I hand-reared four wolf pups, sleeping with them on a mattress for six weeks,” he said. “It had a profound effect. It was the first wolf job I ever got in my life. It turned into my career.”

From there he went on to study wild wolves on Isle Royale in Michigan, and then to work with L. David Mech, a pioneering wolf biologist who is senior scientist with the U.S. Geological Survey and an adjunct professor at the University of Minnesota. Eventually, he went to Yellowstone to work on restoring wolves to the park.

He said ethical questions about keeping wild animals in captivity are difficult, even when every effort is made to enrich their lives. But places like Wolf Park provide great value, he said, if they can get people “to think about the plight of wolves across the world, and do something about it.”

In today’s environment, “with conservation on the run, nature on the run, you need them,” he added.

Then he said what all wolf specialists say: That even though wolf pups look like dogs, they are not, that keeping a wolf or a wolf-dog hybrid as a pet is a terrible idea.

“If you want a wolf,” he said, “get a dog.”

2283. Of a Billion Dogs in the World, 750 Million Are Stray

By James Gorman, The New York Times, April 18, 2016

Territorio de Zaguates (Land of the Strays), a feral dog santuary in Costa Rica with 700 dogs. Costa Rica has an estiamted 1 million feral dogs.

MONTAGUE, Mass. — Think of all the dogs out there: labradors and poodles and labradoodles; huskies and westies and dogues de Bordeaux; pit bulls and spaniels and lovable mutts that go to doggy day care.

Add them up, all the pet dogs on the planet, and you get about 250 million.

But there are about a billion dogs on Earth, according to some estimates. The other 750 million don’t have flea collars. And they certainly don’t have humans who take them for walks and pick up their feces. They are called village dogs, street dogs and free-breeding dogs, among other things, and they haunt the garbage dumps and neighborhoods of most of the world.

In their new book, “What Is a Dog?,” Raymond and Lorna Coppinger argue that if you really want to understand the nature of dogs, you need to know these other animals. The vast majority are not strays or lost pets, the Coppingers say, but rather superbly adapted scavengers — the closest living things to the dogs that first emerged thousands of years ago.

Other scientists disagree about the genetics of the dogs, but acknowledge that three-quarters of a billion dogs are well worth studying.

The Coppingers have been major figures in canine science for decades. Raymond Coppinger was one of the founding professors at Hampshire College in Amherst, and he and Lorna, a biologist and science writer, have done groundbreaking work on sled dogs, herding dogs, sheep-guarding dogs, and the origin and evolution of dogs.

“We’ve done everything together,” he said recently as they sat on the porch of the house they built, set on about 100 acres of land, and talked at length about dogs, village and otherwise, and the roots of their deep interest in the animals.

Both had dogs as children. Lorna had several kinds. An uncle brought Ray his first dog, a pup from a female that hung around a loading ramp at a chemical plant in Cambridge, Mass. “He lived to be 17 — he looked like any other village dog in the world,” he said. After they graduated from Boston University, where they were both undergraduates in the late 1950s, they continued to keep them.

“I gave her a dog for a graduation present,” he said. It was reputedly a collie-shepherd mix.

After they both graduated, they moved to the Amherst area, where Lorna taught Russian and received a master’s degree in wildlife biology and Ray pursued a Ph.D. in zoology, both at the University of Massachusetts. They did field studies together, but on different subjects, and then dove deeply into the canine world.

A neighbor raced sled dogs, and one thing led to another until Dr. Coppinger started racing them himself and they had a hundred dogs housed in cement dens on a hill behind his house. In 1969, he joined Hampshire College as part of the founding faculty, and continued researching energy expenditure in the dogs. He also developed a winning strain by hybridizing Alaskan village dogs with Border collies.

For the first time in their lives together, the Coppingers are now without any dogs at home, and they talk with some nostalgia, more about the bad dogs than the good. Like Jane.

“Worst dog I ever had,” Dr. Coppinger said. “I could tell you a thousand bad stories about Jane.”

“But,” he said, “put her on a mountain pass behind 3,000 sheep, and she’d worry them all the way up the mountain and pick up the strays and everything.”

They don’t miss having dogs by the score, but Ms. Coppinger said, “I miss the pet dogs.” The last, who died in 2013, was Poppyseed Shackleton, a Jack Russell terrier who belonged to their grandchildren, but lived with them.

One benefit, however, is that they are enjoying observing a flood of wildlife that avoided their land when so many dogs were around — vultures, foxes, deer and other animals.

In the early 1970s, they began studying sheep-guarding dogs and traveled around the world finding dogs that sheep herders used. They brought some home and helped develop the Anatolian shepherd breed in the United States, and started a livestock guarding-dog project at Hampshire to study how effective dogs were in protecting sheep and other livestock.

Challenging Science

In 2001, their book “Dogs: A Startling New Understanding of Canine Origin, Behavior & Evolution” challenged the way scientists thought about the beginnings of dogs.

They argued against the widely held view that one day a hunter-gatherer grabbed a wolf pup from a den and started a breeding program. Instead, they argued, dogs domesticated themselves.

Some wild canines started hanging around humans for their leftovers and gradually evolved into scavengers dependent on humans. Not everyone in canine science shares that view today, but many researchers think it is the most plausible route to domestication.

During their travels over the years — to look for sheepdogs, to introduce them to sheep farmers who hadn’t used dogs, to attend conferences — they noticed dogs in the street wherever they went, and after a while they began to think about the dogs’ lives.

“They were so much more interesting than what we’d ever done before,” Dr. Coppinger said. “Here were animals that had their own unique kind of social behaviors. So we started to study them.”

That was in the early 1990s. He worked with Luigi Boitani of La Sapienza University of Rome, who was studying urban dogs that lived off garbage. “I taught classes in the Mexico City dump,” Dr. Coppinger said. And the Coppingers continued to observe village dogs around the world.

They argue in their new book that these dogs “are not mongrels or strays,” as is often assumed. Some lost pets do wander into groups of village dogs. But by and large, these dogs are much the same around the world, whether in Africa, Mongolia, China or the Americas.

Dr. Coppinger said he was once told by a Navajo sheep herder that a good herding dog was “not too big and not too small,” which perfectly describes village dogs, too. They are larger in colder climates, but in the tropics, he said, a 30-pound, lion-colored dog is the norm.

They are completely polygamous. “There can be as many fathers to a litter of puppies as there are puppies to a litter,” Dr. Coppinger said. And after about 10 weeks, the puppies fend for themselves. Most of the pups don’t survive, as is the case with many wild animals.

They have remarkably varied connections to human beings. Some live completely on their own at dumps. Some are neighborhood dogs, recognized and perhaps given handouts by people who live in a certain area. Others may feed and breed on their own, but spend nights at the homes of people. Sometimes they are adopted by people. But really, Dr. Coppinger says, it is the dogs who adopt humans.

The number of dogs that can survive in a city or a neighborhood or at a dump is determined by the available garbage. The Coppingers calculated that in the tropics it takes about 100 people to produce enough garbage to support seven free-living dogs.

There is precious little funding for studying these dogs, except in the context of preventing rabies, which is an enormous problem, with close to 60,000 human deaths a year, mostly from dog bites. But some scientists have tracked their behavior. Sunil K. Pal in India has studied them and written a number of papers on their social lives and behavior.

Why Wolves Aren’t Dogs

The Coppingers were joined for the recent conversation at their home by Kathryn Lord, a former student of Dr. Coppinger and now a researcher at Hampshire College, who studies the development and reproductive behavior of dogs, including village dogs. She shared her insights on what makes a dog a dog, and not a wolf, for example. Wolf puppies depend on their parents and other adults regurgitating partly digested food.

“This is all but lost in dogs,” she said. It does happen, but reports suggest that in village dogs it may occur several times a week.

Among wolves in the wild, she said, “it’s seven times a day,” and it is an uncontrollable reflex. In one experiment, she tried testing adult wolves by putting them into a pen with unrelated pups after a big steak meal.

“They’d actually run around with their heads in the air to avoid the puppies,” she said. “Eventually they’d lose their lunch.” At which point they would run off and let the youngsters have at it.

The point the Coppingers and Dr. Lord make about these behaviors is not that dogs are somehow less caring or noble than wolves, but how perfectly adapted they are to the lives they lead.

They don’t need to be big and strong to bring down prey. They don’t need the kind of parental care and hunting instruction that wolf pups get. As Dr. Lord said, dog pups don’t need to catch and kill anything. “They need to walk up to a rotten melon and eat it, which they can do at 10 weeks.”

Puppies, after they are weaned, cannot compete with adults, so unless disease or dogcatchers have put a dent in the adult population, most of them starve. They have a true superpower in reserve, however, that can help them escape their fate. They can convince a human to feed them.

Dr. Coppinger recalled a woman in South Africa who had many dogs in and around her house. He asked her how it happened that she had so many dogs. “I don’t know,” he recalled the woman saying. “They just keep coming.”

But what are village dogs? Are they a breed, or a superbreed apart? Or are they just a mixture of many breeds with origins too messy to trace?

Adam Boyko, a biologist at the Cornell University College of Veterinary Medicine, who was inspired to pursue canine science by the Coppingers’ 2001 book, has also compiled DNA from village dogs around the world. One of his research papers concluded that village dogs in Mongolia are at the center of dog diversity. That suggests that they are geographically nearest to the place where dogs first evolved.

Other evidence has suggested that dogs originated in Europe or China, however, and Dr. Boyko is one of a number of participants in a major study being led by Greger Larson at Oxford to use ancient DNA and fossils to clear up some of the confusion about the origins of dogs.

And other village dogs seem to have different genetic makeup. For example, Dr. Boyko and his colleagues analyzed DNA samples from village dogs on remote islands in Fiji and French Polynesia that he hoped would show a historical pattern of migration as people and their dogs moved from place to place.

“Almost without exception the dogs were 99 percent European,” he said, meaning their ancestors were dogs on European ships that came to Pacific islands ages ago. Dogs in other places, like Borneo, he said, show almost no trace of European breeds.

In a study published last fall, Wieslaw Bogdanowicz at the Polish Academy of Sciences in Warsaw led an international team of scientists in analyzing the DNA of free-breeding dogs in Eurasia. He concluded that these dogs were different from purebreds and mixed breeds.

“I would like to call them a superbreed,” he said.

He also found that modern European street dogs trace their ancestry to East Asian dogs that migrated with humans to Europe. Earlier studies place that migration sometime between 4,000 and 11,000 years ago.

Beyond that, however, lies the ultimate origin of dogs, which is still clouded in mystery. The consensus among scientists is that dogs evolved from ancient wolves, perhaps ones not found in the fossil record, 15,000 or more years ago.

Dr. Coppinger has suggested that dogs evolved after the invention of agriculture, perhaps around 8,000 years ago, and that today’s village dogs are the closest to these first dogs. But this idea has little support from other scientists.

The Coppingers’ main goal is to draw attention to the world’s vast majority of dogs that are hidden in plain sight. They represent a treasure trove of scientific information.

Although the Coppingers recognize the social cost of animals that are unvaccinated and running free, they argue that killing the dogs, as some countries do during rabies epidemics, does not help. It’s impossible to kill them all, and because they breed rapidly, the population quickly rebounds.

Nor do the Coppingers have any sympathy for rescue groups that, as Dr. Coppinger puts it, “kidnap and mutilate” street dogs from the Caribbean and elsewhere to bring them to American shelters to live as pets, “where they are made totally dependent and entirely restricted.” This is supposed to benefit the dogs, but Dr. Coppinger argues that they are taken from a rich social environment, with many dogs, to lives of relative isolation.

What to do? The Coppingers suggest a simple answer. One way or another village dogs depend on garbage. If society wants fewer dogs in the street, there’s a surefire solution.

Less garbage.