Evolution of Dogs Through Time and Geography

Dogs have undergone significant changes over time and across different regions, resulting in the incredible diversity we see today.

Early studies suggest that dogs originated from gray wolves in Asia around 15,000 to 30,000 years ago.

These early dogs were likely attracted to human camps and settlements, where they scavenged for food and learned to coexist with humans.

As humans migrated and settled in various parts of the world, their dogs followed, leading to the development of distinct breeds and characteristics.

The earliest archaeological evidence of dog domestication comes from a site in Germany, where the remains of dogs have been dated back to around 14,200 years ago.

Genetic studies indicate that the grey wolf is the closest living relative of the dog, but the exact timing of the dog's lineage is difficult to date due to incomplete lineage sorting and post-domestication gene flow.

The genetic divergence between the dog's ancestor and modern wolves occurred over a short period of time, making it hard to pinpoint an exact date. This divergence is estimated to have occurred between 20,000 and 40,000 YBP.

Studies suggest that the population of wolves ancestral to the dog outnumbered all other wolf populations prior to genetic divergence, and after divergence, the dog population underwent a significant reduction in numbers.

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The genetic divergence between the dog's ancestor and modern wolves is a fascinating topic. Studies indicate that this divergence occurred between 27,000 and 40,000 YBP.

Genetic studies have given conflicting results for the timing of this divergence due to factors like incomplete lineage sorting and post-domestication gene flow.

The date of divergence does not necessarily indicate the start of the domestication process, but it does provide an upper boundary. Recent studies suggest that the genetic divergence occurred between 20,000 and 40,000 YBP.

A 2013 study indicated a divergence time of 19,000-32,000 YBP based on mitochondrial DNA sequencing of ancient wolves and whole genome sequencing of modern dogs and wolves.

Another study in 2014 suggested a time frame of 11,000-16,000 YBP, but this was based on the modern wolf's mutation rate, which may not be accurate.

In 2015, a Pleistocene wolf from the Taymyr Peninsula was found to have diverged from the ancestors of both modern wolves and dogs, with an age of 35,000 YBP.

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This age was used to calibrate the wolf's mutation rate, indicating that the genetic divergence between the dog's ancestor and modern wolves occurred before the Last Glacial Maximum, between 27,000 and 40,000 YBP.

A 2017 study compared the nuclear genome of three ancient dog specimens and found evidence of a single dog-wolf divergence occurring between 36,900 and 41,500 YBP.

Prior to genetic divergence, the population of wolves ancestral to the dog outnumbered all other wolf populations, and after divergence the dog population underwent a population reduction to be much lower.

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The first dogs were certainly wolflike, but the changes that occurred as they diverged from wolves are not well understood. Identifying the earliest dogs is difficult because the key morphological characters used to differentiate them from wolves were not yet fixed during the initial phases of domestication.

The size and position of teeth, dental pathologies, and size and proportion of cranial and postcranial elements are the characteristics used by zooarchaeologists to differentiate domestic dogs from wild wolves. However, these traits were not yet fixed during the initial phases of domestication.

The fossil record suggests an evolutionary history that may include both morphologically dog-like wolves and wolf-like dogs. This is because the range of natural variation among these characters that may have existed in ancient wolf populations is unknown.

Early selection may have favored a wolf-like morphology if the earliest dogs followed humans scavenging on carcasses they left behind. This is a possible scenario, but it's still a topic of debate among scientists.

The most widely accepted earliest dog remains are those of the Bonn-Oberkassel dog, which date to 15,000 years Before Present (YBP). This is a significant find, but there are earlier remains dating back to 30,000 YBP that are still debated as to whether they are dogs or wolves.

So, what is a dog? A dog is a domestic mammal of the family Canidae and the order Carnivora.

Dogs are a subspecies of the gray wolf, and they're also related to foxes and jackals.

One of the most interesting things about dogs is that they're one of the two most ubiquitous and most popular domestic animals in the world, with cats being the other.

Dogs have been living with humans for more than 12,000 years, serving as hunting companions, protectors, objects of scorn or adoration, and friends.

They've evolved from the gray wolf into more than 400 distinct breeds.

The evolutionary process of dogs is a fascinating story that spans thousands of years. It's believed that dogs were first domesticated from gray wolves around 15,000 years ago.

Their ancestors were highly adaptable and resourceful, able to thrive in a variety of environments. This adaptability played a key role in their ability to coexist with humans.

Dogs were initially valued for their hunting skills, helping early humans to catch prey and provide food for their families. This partnership laid the foundation for their eventual domestication.

Genetic changes have been a crucial aspect of the evolutionary process of dogs and wolves. The genetic divergence between dogs and wolves occurred over a short period of time, making it difficult to date.

Studies indicate that an extinct Late Pleistocene wolf is the nearest common ancestor to the dog. This ancestor is believed to have lived hundreds of thousands of years ago.

The genetic changes that have occurred in dogs are a result of domestication, with modern wolves not being directly ancestral to them. In fact, there have been only tens of thousands of generations of dogs since domestication, resulting in few mutations between dog and wolf.

Admixture between dogs and wolves has also occurred, with studies indicating that dogs and wolves have interbred since domestication. This has led to gene flow from dogs into wolves, with 7-25% of the genome of European and Middle Eastern wolves showing contributions from dogs.

The genetic changes in dogs have also led to the development of unique characteristics, such as the black coat of North American wolves, which is the result of a single introgression from early Native American dogs. This introgression occurred between 1,600 and 7,200 years before present.

In some cases, gene flow has occurred in the opposite direction, with wolves contributing to the genetic makeup of dogs. For example, the EPAS1 allele associated with high-altitude oxygen adaptation has been contributed by a ghost population of an unknown wolf-like canid.

Epigenetics plays a significant role in the domestication of wolves, leading to the development of domestication syndrome.

Differences in hormonal expression associated with domestication syndrome are linked to epigenetic modifications, including 68 significantly different methylated sites found in dogs compared to wolves.

These sites are linked to two neurotransmitter genes associated with cognition, and one of them, OXTR, is directly associated with the dog's social behavior and has been caused through epigenetic methylation.

DNA methylation differences have been found between wolves and dogs, and between different dog breeds, implying that epigenetic factors may have been important for both dog domestication and the divergence of dog breeds.

The social environment of the dog ancestor induced neuro-physiological changes that caused an epigenetic cascade, leading to the rapid development of domestication syndrome, according to the Active Social Domestication theory.

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Around 50 million years ago, the Carnivora split into two main divisions: caniform (dog-like) and feliform (cat-like). This split marked the beginning of the Carnivora's evolutionary journey.

The first identifiable member of the dog family, Prohesperocyon wilsoni, emerged around 40 million years ago in southwest Texas. Its fossils have been found in this region.

Prohesperocyon probably had slightly longer limbs than its predecessors and had parallel and closely touching toes, which differ from the splayed arrangements of the digits in bears. This unique feature suggests a more agile and adaptable species.

The Canidae soon divided into three subfamilies: Hesperocyoninae, Borophaginae, and Caninae. Each of these subfamilies diverged during the Eocene epoch.

Members of each subfamily showed an increase in body mass with time, and some exhibited specialized hypercarnivorous diets that made them prone to extinction. This trend highlights the complex relationships between diet, body size, and survival.

The Miocene epoch was a time of great change and migration for many species. Around 8 Mya, the Beringian land bridge allowed members of the genus Eucyon to enter Asia from North America.

This land bridge provided a vital connection between the two continents, enabling the Eucyons to continue on to colonize Europe. They were among the first of many species to make this journey.

The Miocene epoch was a key period in the evolutionary process, marked by the movement of species across vast distances. This period of migration paved the way for the diversification of species that would follow.

The Pliocene epoch was a pivotal time in the evolution of canids. Around 5 million years ago, the canine radiation began in North America, where the Canis, Urocyon, and Vulpes genera developed from canids.

These canids were successful due to the development of lower carnassials that could perform both mastication and shearing.

The first members of Canis emerged in the Old World around 5 million years ago, evolving from the Eucyon. Canis lepophagus, a small and sometimes coyote-like canid, appeared in North America around 4-5 Mya.

C. latrans, the coyote, is thought to have descended from C. lepophagus. The formation of the Isthmus of Panama, around 3 Mya, allowed canids to invade South America.

The gray fox (Urocyon cinereoargentus) and the now-extinct dire wolf (Aenocyon dirus) were among the North American lineages that found their way to South America.

Domestication was a game-changer for humans, and it all started with dogs. Animal domestication is a coevolutionary process in which a population responds to selective pressure while adapting to a novel niche that included another species with evolving behaviors.

Dogs were the first domesticated species, and their domestication had a profound influence on the course of early human history and the development of civilization. The association of dogs with humans may have allowed dogs to enter into a domestic relationship with humans during the Pleistocene.

Genetic studies suggest a domestication process commencing over 25,000 years ago, in one or several wolf populations in either Europe, the high Arctic, or eastern Asia. The wolf population(s) that were involved are likely to be extinct.

Around 10,000 years ago, agriculture was developed, resulting in a sedentary lifestyle, and the dog's phenotype began to diverge from its wolf ancestors, including variance in size. Two population bottlenecks have occurred to the dog lineage, one due to the initial domestication and one due to the formation of dog breeds.

Dogs may have traveled a commensal pathway into domestication, and their ability to coexist with humans was likely due to their family, Canidae, and the right temperament.

Domestication of dogs is believed to have started around 15,000 years ago with the association of wolves and hunter-gatherers.

The earliest domesticated dogs were derived from grey wolves, and genetic studies suggest a domestication process commencing over 25,000 years ago in one or several wolf populations in Europe, the high Arctic, or eastern Asia.

Dogs were first domesticated in East Asia, with an initial phase beginning in China or Southeast Asia 33,000 years ago.

The first dogs were likely used for hunting and companionship, and their value as hunting partners gave them status as a living weapon.

The earliest generally accepted dog remains were discovered in Bonn-Oberkassel, Germany, and dated to 14,223 years ago.

These ancient dogs were buried with their human companions, suggesting emotional or symbolic ties between humans and dogs.

Dogs were an integral part of early human history, influencing our relationship with the natural world and playing a significant role in the development of civilization.

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The first dog breeds developed in arctic northeastern Siberia, specifically on Zhokhov Island, around 9,500 years before present.

The archaeological discoveries at the Zhokhov site are a testament to the resourcefulness of early dog owners, with remains of dog harness straps similar to those used by the modern Inuit.

Tools made from obsidian transported from 1,500 kilometres away were also found, suggesting long-distance transport through the use of sled dogs.

The optimal maximum size for a sled dog is 20-25 kg based on thermo-regulation, and the ancient sled dogs were between 16 and 25 kg.

The study proposes that the evolution of the dog proceeded in three stages, with the first being natural selection based on feeding behaviour within the human-ecological niche.

The Zhokhov dogs are the oldest known dogs to exhibit colour patterns, with black colour patterns on their backs that helped distinguish them from white arctic wolves.

As humans, we've had a special bond with dogs for thousands of years, and it's hard to pinpoint exactly when and how it started.

Dogs have an uncanny ability to sense who likes them and who doesn't, often making friends with the people who seem to dislike them the most.

In American history, it's common to find families with two dogs: a large dog for guarding and a small dog for companionship, rat-killing, and alerting.

The small dog's size made it an easier companion, and its role in the household was often to be a playmate for children or a guardian.

Dogs were created by humans in different ways, living with us in a way that wolves don't, and this has led some to consider them a separate species from wolves.

Some breeds are so altered by human breeding that they're incapable of giving birth naturally and require C-sections.

It's not fair to produce animals that aren't healthy, and it's bad for both the animal and the people who love them but are left heartbroken by their early deaths due to inherited diseases.

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Dogs first entered Japan around 9,500 years before present (YBP).

The oldest fossil of a dog found in Japan dates back to this time.

As the climate warmed up, the Jōmon people on Honshu started hunting sika deer and wild boar instead of megafauna like Naumann's elephant and Yabe's giant deer.

They used smaller, triangular points for their arrows, which was a new hunting technology.

Dogs were treated as valuable hunting partners and were given proper names, just like family members.

They even had separate burials with markers and grave-goods, showing how much they were valued.

In Japan, hunting dogs still play a crucial role in hunting today, just like they did thousands of years ago.

Their skills as hunters earned them a special status, and the most skilled ones were even venerated.

The Jōmon people's treatment of dogs is not unique, as other early Holocene deciduous forest forager societies in Europe and North America also conducted intentional dog burials.

Dogs entered Island Southeast Asia and Oceania at least 10,000 to 5,000 years before present, arriving with Paleolithic maritime hunter-gatherers.

The oldest archaeological remains of dogs in Island Southeast Asia and Oceania is a dog burial in Timor, dated to around 3,500 years before present.

Dogs were widely distributed in southern China, then dispersed through Southeast Asia into New Guinea and Oceania, but were replaced in China 2,000 years before present by dogs of other lineages.

In Island Southeast Asia, dogs were deeply valued as hunting companions, particularly for wild boar, and were often buried near or beside human graves in archaeological sites.

The Austronesian domesticated dogs originally carried by the Lapita Culture migrations were eaten to extinction in many islands since ancient times, causing a marked discontinuity in the genes of domesticated dogs.

Dogs were later reintroduced from neighboring Papuan groups and were subsequently carried eastward into Polynesia by post-Lapita Austronesian migrations, reaching as far as Hawaii and Aotearoa.

The Near East played a significant role in the history of dog domestication, particularly in the migration of dogs to Africa. In 2020, ancient dog genomes revealed that modern dogs in sub-Saharan Africa share a single origin from the Levant, dated to 7,000 years before present (YBP).

Dogs from the Levant entered Africa, bringing with them a new genetic lineage. This mirrors the gene flow of humans from the Levant into Africa during the Neolithic period, along with cattle.

One of the oldest dog remains found in Africa dates back to 5,900 YBP, discovered at the Merimde Beni-Salame Neolithic site in the Nile Delta, Egypt. This suggests that dogs arrived in Africa at the same time as domestic sheep and goats.

The dog then spread north to south down Africa beside livestock herders, with remains found in archaeological sites dated 925-1,055 YBP at Ntusi in Uganda, dated 950-1,000 YBP at Kalomo in Zambia, and then at sites south of the Limpopo River and into southern Africa.

Today, the southern African Rhodesian Ridgeback retains 4% pre-colonial ancestry, a testament to the dog's long history in Africa.

It's fascinating to think about what life was like 23,000 years ago in Siberia. Around 30,000–40,000 YBP, the evolution of the dog began to take shape. The process commenced with natural selection based on feeding behaviour within the ecological niche formed through human activity.

Dogs were selectively bred to be either sled dogs or hunting dogs, with the optimal maximum size for a sled dog being 20–25 kg based on thermo-regulation. The ancient sled dogs found in Siberia were between 16 and 25 kg, and the same standard has been found in the remains of sled dogs from this region 2,000 YBP and in the modern Siberian husky breed standard.

The domestic dog was present on what is now Zhokhov Island, arctic northeastern Siberia, 9,500 YBP. The archaeological discoveries at the Zhokhov site include the remains of dog harness straps similar to those used by the modern Inuit, and tools made from obsidian transported from 1,500 kilometres away.