Domestication of the dog

The domestication of the dog was the process which led to the domestic dog. Dogs are very special animals because they were the first pets that humans had. All dogs today come from an old type of wolf that is no longer alive. These wolves were different from the wolves we know now, and they slowly changed to become the dogs we love today.

The change from wolf to dog happened between 20,000 and 40,000 years ago, around the time when the world was going through a big cold period called the Last Glacial Maximum. Dogs are similar to grey wolves, but they are their own group now. This happened because over many years, some wolves started to live closer to humans. These wolves were less scared of people and were friendlier, which helped them survive better.

Dogs were very important for humans, especially for people who moved around a lot to find food, called hunter–gatherers. Dogs could help watch for danger, bring back things, and even warn about problems. Because of these helpful wolves, humans and dogs began to live together. This friendship between humans and dogs is one of the biggest changes in human history, showing how animals and people can work together and help each other.

Timing

The domestication of dogs happened long before farming began. Around 11,400 years ago, during a time called the Holocene, people in the Near East started to live with wild animals like aurochs, boar, sheep, and goats. Where dogs were first domesticated is still being discussed, but most evidence points to Eurasia, especially areas like Central Asia, East Asia, and Western Europe.

The oldest remains of dogs have been found in Western Europe, from places like the Erralla site in Spain. These dogs lived during cultures such as the Magdalenian, Epigravettian, Azilian, and Laborian. One famous example is the Bonn–Oberkassel dog, which lived about 14,500 years ago and was buried with a person. Other old dog remains have been found in places like Grotta Paglicci and Kesslerloch.

By the end of the last Ice Age about 11,700 years ago, different groups of ancestral dogs had spread across places like the Levant, Karelia, near Lake Baikal, and even ancient America. Recent studies suggest that dogs may have been first domesticated in Siberia between 26,000 and 19,700 years ago, and then spread to other parts of the world. However, more digging is needed to find ancient dog remains from that time and place.

Divergence from wolves

Genetic studies show that the grey wolf is the closest living relative of the dog. Researchers have tried to understand the dog's lineage by studying DNA from modern dogs and wolves, but the results have been mixed. This is because an extinct type of wolf is the nearest common ancestor to dogs, and modern wolves are not directly ancestral to them. The genetic split between the dog's ancestor and modern wolves happened over a short period, making it hard to pinpoint exactly when. This is further complicated by cross-breeding between dogs and wolves after domestication. Additionally, there have been relatively few generations of dogs since domestication, which makes dating the timing of domestication difficult.

During the Late Pleistocene era, a time of glaciation and climate change, grey wolves experienced a population decline. Despite this, they survived while many other large animals did not. Grey wolves showed considerable diversity in size and shape, possibly due to differences in their prey. Some ancient wolves had features that suggest they were adapted to eating bones and carcasses, which may have helped them survive.

For a long time, scientists believed that dogs evolved from the modern grey wolf. However, a study published in 2014 showed that dogs are actually descended from an extinct type of wolf. The genetic evidence suggests that the divergence between the lineage that led to the domestic dog and modern wolves occurred between 20,000 and 40,000 years ago. This provides an upper boundary for when domestication began, though the actual process likely started later.

Recent studies have also suggested that dogs may have originated in different regions, with some evidence pointing to Southeast Asia, Central Asia, the Middle East, and Europe. The genetic diversity among dogs from Southeast Asia is greater, suggesting this region may have been a key place of origin. However, fossil evidence of dogs in Europe dates back to around 17,000 years ago, while fossils in far eastern Russia are only about 12,000 years old. This discrepancy might be due to differences in fossil preservation in various regions.

Overall, the origin of dogs remains a topic of ongoing research, with evidence pointing to multiple possible regions and timelines. The genetic and fossil records continue to provide clues about how and where dogs first diverged from their wild ancestors.

Dog domestication

Animal domestication is a process where animals change to fit better with human life. Dogs were the first animals to live with humans, starting more than 17,000 years ago with wolves. This happened before people began farming or keeping other animals like cows and sheep.

Scientists think dogs began living with humans around 25,000 years ago from wolves in places like Europe or Asia. We know dogs came from wolves, but the exact time and place are still being studied. Dogs changed in size and looks from their wolf ancestors as they started to live closer to people. Over time, dogs became very important to early human life and helped shape how humans lived and traveled.

Dogs and humans share a special bond. They both live in groups and can work together. Some think dogs learned to live with humans by being friendly and not scary. Others believe wolves started following humans because they liked the food and safety near human fires. Either way, dogs and humans helped each other survive and thrive together.

First dogs

Dogs domesticated in East Asia

Savolainen’s study of mitochondrial DNA shows that dog domestication began in China or Southeast Asia around 33,000 years ago. A second phase occurred 18,000 years later, with dogs migrating from Southeast Asia to Africa and the Middle East. They arrived in Europe about 10,000 years ago, leading to the development of modern dog breeds.

Savolainen noted that many studies contradicting the East Asian origin of dogs did not include samples from China or Southeast Asia.

Dogs domesticated in Siberia 23,000 years ago

Locating the origin of dogs is challenging due to limited data on extinct wolves, small morphological changes during early domestication, and the lack of accompanying human artifacts.

In 2016, a genetic study found that ancient and modern dogs belong to Eastern and Western Eurasian groups. Another 2017 study suggested a single dog-wolf divergence between 36,900 and 41,500 years ago, followed by a split between Eastern and Western Eurasian dogs 17,500–23,900 years ago, indicating dog domestication occurred between 20,000 and 40,000 years ago.

A 2021 review suggests dogs were domesticated in Siberia 23,000 years ago by ancient North Siberians. These dogs later spread with human migrations into the Americas and across Eurasia. The harsh climate of the Last Glacial Maximum may have brought humans and wolves closer together, leading to domestication.

Mitochondrial DNA shows most modern dogs belong to four haplogroups: A, B, C, and D, with most in haplogroup A. The oldest known split in dog lineages occurred around 22,800 years ago within haplogroup A. Human and dog migrations often coincided, suggesting dogs followed human movements.

A 2018 study of complete mitogenome sequences from 555 modern and ancient dogs showed a population increase around 23,500 years ago, coinciding with the proposed divergence of dogs from wolves. A ten-fold increase occurred after 15,000 years ago, aligning with human population growth.

Admixture

Studies show mixing between the ancestor of dogs and wolves and golden jackals. Since domestication, there has been little gene flow from wolves to dogs but significant flow from dogs to wolves. Some wolves are related to ancient and modern dogs. Small amounts of gene flow were detected between coyotes and ancient American dogs, and between African wolves and African dogs. East Asian wolves have 20% dog genome contributions, while European and Middle Eastern wolves have 7–25%. The β-defensin gene for black coat colour in North American wolves came from early Native American dogs between 1,600 and 7,200 years ago. Dogs and wolves in the Himalayas and Tibetan Plateau carry the EPAS1 allele for high-altitude adaptation from an unknown wolf-like canid. This canid contributed 39% to the Himalayan wolf’s genome. Limited gene flow occurred in arctic dogs.

Magdalenian dogs

The earliest Palaeolithic dog-human burial was discovered in 1914 at the Magdalenian site of Bonn-Oberkassel, Germany. The dog, dated to 14,223 years ago, was not a local wolf. Other dog remains from the Magdalenian and Azilian cultures are older, such as Erralla in Spain (17,410–17,096 years ago) and Abri le Morin in France (15,132–14,155 years ago).

The Erralla dog, identified in 1985, was confirmed as a dog through genotyping and morphometric studies. It belonged to mitochondrial haplogroup C, shared with other Palaeolithic Western European dogs, including the Bonn-Oberkassel dog. This suggests Magdalenian hunter-gatherers brought dogs during their expansion from the Franco-Cantabrian region after the Last Glacial Maximum.

The Bonn-Oberkassel dog was buried with two humans, a man aged 40 and a woman aged 25, sprayed with red hematite powder and covered with basalt blocks. The dog died young from canine distemper and could not have survived without human care, indicating emotional bonds between humans and dogs.

Ice Age dogs

Sequencing of ancient dog genomes shows they share a common ancestry from an extinct wolf population distinct from modern wolves. By the end of the last Ice Age (11,700 years ago), five ancestral lineages diversified, seen in dog samples from the Neolithic Levant (7,000 years ago), Mesolithic Karelia (10,900 years ago), Mesolithic Baikal (7,000 years ago), ancient America (4,000 years ago), and the New Guinea singing dog (present day).

Modern dog populations are classified into Arctic/Americas, East Asian, and West Eurasian lineages. The Arctic/Americas lineage includes modern arctic breeds, a 9,500-year-old Zhokhov Island dog, ancient pre-European contact American dogs, mid-Holocene Lake Baikal dogs, historical Siberian dogs, and Yamalo-Nenets Autonomous Okrug dogs. The East Asian lineage includes dogs from China, Vietnam, Island Southeast Asia, the dingo, and the New Guinea singing dog. The West Eurasian lineage includes ancient Levantine and Near Eastern dogs, ancient and modern European dogs, modern African dogs, and Bronze Age Eurasian Steppe dogs.

Ancient and modern European dogs are more closely related to arctic dogs than Near Eastern dogs, indicating a major admixture event in Europe. A Mesolithic Veretye, Karelia dog (~10,000 years ago) had ancestry from both Arctic (~70%) and Western Eurasian (~30%) lineages. The Zhokhov Island dog (9,500 years ago) had no Western Eurasian ancestry, showing it had not yet reached the Siberian Arctic. The 7,000-year-old Neolithic European dog was a mix of Karelian and Levantine lineages, and a 5,000-year-old Swedish Neolithic dog was the ancestor of 90-100% of modern European dogs, suggesting a population replacement in Europe.

Siberian dogs from 9,500–7,000 years ago showed Arctic ancestry, but later introduced dogs from the Eurasian Steppe and Europe caused genetic mixing. Bronze Age Eurasian Steppe dogs had 40% ancient arctic and 60% ancient Near East ancestry. Yamalo-Nenets dogs from 2,000 years ago were less related to Eurasian Steppe and European dogs than those from 1,000 years ago, indicating connections through trade networks. Siberian Huskies are related to historical East Siberian and ancient Lake Baikal dogs, showing the survival of the ancient arctic lineage in some modern breeds.

Ancient dog and human genomes generally matched, but some differences existed. Dogs in the Neolithic Levant and Chalcolithic Iran had the same dogs despite different human populations. Neolithic Irish and German dogs were linked to northern European hunter-gatherers, while humans were related to Levantine people. Bronze Age Pontic-Caspian steppe and Corded Ware culture dogs in Germany had not changed with human population shifts. European dogs are more closely related to Siberian and ancient American dogs than to the New Guinea singing dog, reflecting early connections between humans in the Americas and Europe. Lake Baikal region humans 18,000–24,000 years ago contributed to Native American ancestry but were later replaced. By 7,000 years ago, Lake Baikal dogs still showed relationships with Europe and the Americas, indicating shared population structures for dogs and humans across northern Eurasia.

A major ancestry transformation in ancient human genomes coincided with Neolithic farmer expansions from the Near East into Europe, accompanied by dogs. Steppe pastoralist expansions transformed human ancestry but had little impact on European dog populations. Steppe pastoralists also expanded eastwards but had little impact on East Asian people. Many Chinese dogs result from mixing between a 3,800-year-old western Eurasian Srubnaya culture dog and the ancestor of the dingo and New Guinea singing dog. Modern Siberian dogs show ancestry from 7,000-year-old Lake Baikal dogs but little New Guinea singing dog ancestry.

The AMY2B gene aids in starch digestion. Early dogs had varying abilities to digest starch, which became widespread thousands of years later with agriculture.

Dogs migrated with humans but not always together, sometimes moving between human groups as cultural or trade items. Dogs spread across Eurasia and into the Americas without major human population movements, remaining a mystery.

First dogs as a hunting technology

During the Upper Paleolithic (50,000–10,000 years ago), increased human populations, advances in technology, and climate change altered prey densities, making scavenging important for some wolves. Adaptations like tameness, small size, and reduced reproduction age reduced hunting efficiency, leading to obligated scavenging. Whether earliest dogs were scavengers or played roles as companions or hunters in their spread is unknown.

Researchers suggest a hunting partnership between humans and dogs drove domestication. Petroglyphs from 8,000 years ago in Saudi Arabia depict dogs in hunting scenes, sometimes on leashes. The transition from the Late Pleistocene to the early Holocene brought warmer, wetter conditions and forest growth, replacing open habitats. In these forests, hunting dogs helped track and retrieve wounded game, enhancing hunting success where human senses were less effective. Dogs are still used for hunting in forests today.

Arctic breeds

First dog breeds developed in arctic northeastern Siberia

The domestic dog was present on Zhokhov Island, arctic northeastern Siberia, 9,500 years ago. Archaeological finds include dog harness straps similar to modern Inuit ones, polar bear and reindeer remains indicating wide hunting ranges, and obsidian tools from 1,500 km away, suggesting long-distance transport via sled dogs.

Studies show these dogs were selectively bred as sled or hunting dogs, with sled dogs optimally sized at 20–25 kg for thermo-regulation. Ancient sled dogs weighed 16–25 kg, matching modern Siberian husky standards. Other dogs, heavier at 30 kg, were crossed with wolves for polar bear hunting. Dog heads were separated from bodies for ceremonial reasons.

The study suggests dog evolution occurred in three stages after diverging from wolves: natural selection based on feeding behaviour, artificial selection based on tamability, and directed selection for specific tasks. This process began 30,000–40,000 years ago, accelerating until domestication was complete.

Zhokhov dogs are the oldest known with colour patterns, showing black backs to distinguish them from white arctic wolves.

Dogs enter North America from northeastern Siberia

Material culture shows dog harnessing in the Arctic 9,000 years ago. Ancient DNA indicates these dogs are related to modern Arctic dogs and gave rise to the earliest native American dogs. European dogs later replaced these lineages after contact.

The earliest North American dog remains were found in Lawyer's Cave, Alaska, dated to 10,150 years ago. Stable isotope analysis suggests a marine diet. The next earliest dogs were found in Illinois, dated to 9,900 years ago, with diets of freshwater fish. Similar dog burials across Eurasia highlight their importance in hunting for adapting to changing environments during the Pleistocene-Holocene transition.

A 2018 study compared North American and Siberian dog fossils with modern dogs. North American dogs shared a common ancestor dated to 14,600 years ago, diverging from the Zhokhov dog ancestor 15,600 years ago. Koster dogs entered North America 4,500 years after humans, were isolated for 9,000 years, and were replaced by Eurasian dogs after European contact. Pre-contact dogs have a unique genetic signature now extinct, with modern arctic breeds as their closest relatives.

A 2019 study found that dogs brought into the North American Arctic from northeastern Siberia were later replaced by Inuit dogs during their expansion 2,000 years ago. Inuit dogs were more genetically diverse and morphologically divergent. Arctic sledge dogs are descendants of pre-European dog lineages. In 2020, sequencing showed Mexican breeds like the Chihuahua and Xoloitzcuintli retain 4% and 3% pre-colonial ancestry, respectively.

Late Pleistocene wolf admixture

In 2015, the genome of a 35,000-year-old Pleistocene wolf from the Taimyr Peninsula was mapped and compared with modern dogs and wolves. The Taimyr wolf was equally related to dogs and modern wolves but shared more alleles with high-latitude breeds like the Siberian husky and Greenland dog. Greenland dogs show 3.5% Taimyr wolf ancestry, indicating admixture between Taimyr wolves and ancestral dogs of these breeds. This suggests early dogs in high latitudes adapted to new environments through mixing, and modern arctic breeds descend from multiple regions.

A nuclear genome from a 4,800-year-old Newgrange dog in Ireland showed it was male, lacked modern coat length or colour genes, processed starch less efficiently than modern dogs but more than wolves, and had ancestry from wolves not found in other dogs or wolves today. Mutation rates from the Taimyr wolf and Newgrange dog suggest modern wolves and dogs diverged between 20,000 and 60,000 years ago, indicating earlier domestication, earlier arrival in the Arctic, or both. Another view suggests northern breeds trace ancestry to the Taimyr wolf, indicating possible multiple domestication events.

In 2020, the nuclear genome of a 33,000-year-old Yana River wolf showed it was more closely related to the Taimyr wolf than to modern wolves, with gene flow between Yana-Taimyr wolves and Pre-Columbian, Zhokhov, and modern sled dogs. No admixture between sled dogs and modern grey wolves occurred in the past 9,500 years. Greenland sled dogs, isolated since arriving with the Inuit 850 years ago, trace more genomic history to Zhokhov dogs than any other arctic breed. Sled dogs show adaptations to high fat intake, not starch, aligning with Inuit and arctic peoples' diets. This suggests sled dogs adapted to low-starch, high-fat diets of their human companions.

In 2021, a study of four Late Pleistocene northeast Siberian wolves showed they are genetically similar to Taimyr and Yana wolves. These six extinct wolves branched off from the lineage leading to modern wolves and dogs. The 50,000-year-old Tirekhtyakh River, 48,000-year-old Bunge-Toll site, and 32,000-year-old Yana RHS specimens were separate lineages. The 16,800-year-old Ulakhan Sular and 14,100-year-old Tumat specimens cluster with a modern Ellesmere Island wolf, indicating they derive from the same lineage as North American wolves. All six Late Pleistocene wolves share alleles with Arctic dogs, suggesting another extinct wolf population may have contributed to Arctic dog ancestry. Evidence shows four extinct Siberian wolves contributed to modern wolf populations in Shanxi, China, and possibly Chukotka and Inner Mongolia.

Dogs enter Japan

The oldest dog fossil in Japan dates to 9,500 years ago. With the Holocene's warmer weather, temperate deciduous forests spread across Honshu, shifting hunting from megafauna to sika deer and wild boar in dense forests. This led to changes in hunting technology, including smaller arrow points. Studies of Jōmon people on Honshu's Pacific coast show they conducted individual dog burials and used dogs for hunting sika deer and wild boar, as seen in modern Japanese hunting practices.

Hunting dogs are vital to forager societies, often named, treated as family members, and considered distinct from other dogs. They receive special burials with markers and grave-goods, with exceptional hunters or those killed on the hunt sometimes venerated. A dog's value as a hunting partner gives them status as living weapons, with the most skilled elevated to "personhood," similar to skilled hunters in social position both in life and death.

Intentional dog burials with ungulate hunting are also found in early Holocene deciduous forest forager societies in Europe and North America, indicating hunting dogs were a widespread adaptation to forest ungulate hunting across the Holarctic temperate zone.

Dogs enter Island Southeast Asia and Oceania

In 2020, an mDNA study of ancient dog fossils from the Yellow River and Yangtze River basins in southern China showed most ancient dogs fell within haplogroup A1b, like Australian dingoes and pre-colonial Pacific dogs, but in low frequency today. A specimen from the Tianluoshan site (Hemudu culture) in Zhejiang, dating to 7,000 years ago, is basal to the entire lineage. Dogs in this haplogroup were once widespread in southern China, then dispersed through Southeast Asia into New Guinea and Oceania but were replaced in China 2,000 years ago by other lineages.

Dogs entered Island Southeast Asia, Australia, and New Guinea in at least two waves: one with Paleolithic maritime hunter-gatherers by at least 10,000 to 5,000 years ago, and another with Neolithic seafaring Austronesian peoples via Taiwan by at least 5,000 years ago. Neolithic dogs could digest starch, indicating they accompanied humans cultivating cereal crops. The oldest archaeological dog remains in Island Southeast Asia and Oceania are a dog burial in Timor and dingo remains in Australia, both dated to around 3,500 years ago. The former are believed to be from the second wave, and the latter from the first. Austronesian dogs, like the Taiwan dog, were valued as hunting companions, especially for wild boar. In the Philippines, dog remains have been found buried near or beside human graves.

From Island Southeast Asia, Austronesian voyagers carried dogs into Near Oceania. However, unlike in Island Southeast Asia, dogs lost economic importance as hunting animals in Melanesia and Polynesia, which lacked large mammals. They became competitors for food and were eaten. Austronesian dogs carried by Lapita Culture migrations went extinct in many islands. Thus, Austronesian dogs were “lost” during early Near Oceania colonization, causing a discontinuity in dog genes and terms among Austronesians in the Pacific Islands and Island Melanesia compared to other regions. Dogs were later reintroduced from Papuan groups and carried eastward into Polynesia by post-Lapita migrations, reaching Hawaii and Aotearoa. These dogs were food animals, not hunting companions. Genetic studies confirm Polynesian dogs descended from the first wave and are unrelated to Taiwan and Philippines dogs.

Dogs from the Near East enter Africa

In 2020, ancient dog genome sequencing indicated that modern sub-Saharan African dogs originate from the Levant, with an ancestral specimen dated to 7,000 years ago. This mirrors human and cattle gene flow from the Levant into Africa during the Neolithic. Since then, there has been limited gene flow into African dogs until recent centuries. Descendants of a 5,800-year-old Iranian dog and European dogs replaced the Levant dog lineage 2,300 years ago, associated with human migration from Iran and minor European migration. Today, Near Eastern dogs show 81% ancient Iranian and 19% Neolithic European ancestry.

The oldest African dog remains date to 5,900 years ago at Merimde Beni-Salame in Egypt. The next oldest are from Esh Shareinab in Sudan, dated to 5,500 years ago, suggesting dogs arrived from Asia with domestic sheep and goats. Dogs spread north to south with livestock herders, with remains found at Ntusi in Uganda (925–1,055 years ago), Kalomo in Zambia (950–1,000 years ago), and southern Africa. In 2020, ancient dog genome sequencing showed the southern African Rhodesian Ridgeback retains 4% pre-colonial ancestry.