DOG
The domestic dog (Canis lupus familiaris) is a subspecies of the gray wolf (Canis lupus), a member of the Canidae family of the mammalian order Carnivora. The term "domestic dog" is generally used for both domesticated and feral varieties. The dog was the first domesticated animal and has been the most widely kept working, hunting, and pet animal in human history.[citation needed] The word "dog" can also refer to the male of a canine species, as opposed to the word "bitch" which refers to the female of the species.
Recent studies of "well-preserved remains of a dog-like canid from the Razboinichya Cave" in the Altai Mountains of southern Siberia concluded that a particular instance of early wolf domestication approximately 33,000 years ago did not result in modern dog lineages, possibly because of climate disruption during the Last Glacial Maximum. The authors postulate that at least several such incipient events have occurred. A study of fossil dogs and wolves in Belgium, Ukraine, and Russia tentatively dates domestication from 14,000 years ago to more than 31,700 years ago. Another recent study has found support for claims of dog domestication between 14,000 and 16,000 years ago, with a range between 9,000 and 34,000 years ago, depending on mutation rate assumptions. Dogs' value to early human hunter-gatherers led to them quickly becoming ubiquitous across world cultures. Dogs perform many roles for people, such as hunting, herding, pulling loads, protection, assisting police and military, companionship, and, more recently, aiding handicapped individuals. This impact on human society has given them the nickname "man's best friend" in the Western world. In some cultures, however, dogs are also a source of meat. In 2001, there were estimated to be 400 million dogs in the world.
Most breeds of dog are at most a few hundred years old, having been artificially selected for particular morphologies and behaviors by people for specific functional roles. Through this selective breeding, the dog has developed into hundreds of varied breeds, and shows more behavioral and morphological variation than any other land mammal. For example, height measured to the withers ranges from 15.2 centimetres (6.0 in) in the Chihuahua to about 76 cm (30 in) in the Irish Wolfhound; color varies from white through grays (usually called "blue") to black, and browns from light (tan) to dark ("red" or "chocolate") in a wide variation of patterns; coats can be short or long, coarse-haired to wool-like, straight, curly, or smooth. It is common for most breeds to shed this coat.
The domestic dog (Canis lupus familiaris) is a subspecies of the gray wolf (Canis lupus), a member of the Canidae family of the mammalian order Carnivora. The term "domestic dog" is generally used for both domesticated and feral varieties. The dog was the first domesticated animal and has been the most widely kept working, hunting, and pet animal in human history.[citation needed] The word "dog" can also refer to the male of a canine species, as opposed to the word "bitch" which refers to the female of the species.
Recent studies of "well-preserved remains of a dog-like canid from the Razboinichya Cave" in the Altai Mountains of southern Siberia concluded that a particular instance of early wolf domestication approximately 33,000 years ago did not result in modern dog lineages, possibly because of climate disruption during the Last Glacial Maximum. The authors postulate that at least several such incipient events have occurred. A study of fossil dogs and wolves in Belgium, Ukraine, and Russia tentatively dates domestication from 14,000 years ago to more than 31,700 years ago. Another recent study has found support for claims of dog domestication between 14,000 and 16,000 years ago, with a range between 9,000 and 34,000 years ago, depending on mutation rate assumptions. Dogs' value to early human hunter-gatherers led to them quickly becoming ubiquitous across world cultures. Dogs perform many roles for people, such as hunting, herding, pulling loads, protection, assisting police and military, companionship, and, more recently, aiding handicapped individuals. This impact on human society has given them the nickname "man's best friend" in the Western world. In some cultures, however, dogs are also a source of meat. In 2001, there were estimated to be 400 million dogs in the world.
Most breeds of dog are at most a few hundred years old, having been artificially selected for particular morphologies and behaviors by people for specific functional roles. Through this selective breeding, the dog has developed into hundreds of varied breeds, and shows more behavioral and morphological variation than any other land mammal. For example, height measured to the withers ranges from 15.2 centimetres (6.0 in) in the Chihuahua to about 76 cm (30 in) in the Irish Wolfhound; color varies from white through grays (usually called "blue") to black, and browns from light (tan) to dark ("red" or "chocolate") in a wide variation of patterns; coats can be short or long, coarse-haired to wool-like, straight, curly, or smooth. It is common for most breeds to shed this coat.
HISTORY AND EVOLUTION
Domestic dogs inherited complex behaviors from their wolf ancestors, which would have been pack hunters with complex body language. These sophisticated forms of social cognition and communication may account for their trainability, playfulness, and ability to fit into human households and social situations, and these attributes have given dogs a relationship with humans that has enabled them to become one of the most successful species on the planet today.
Although experts largely disagree over the details of dog domestication, it is agreed that human interaction played a significant role in shaping the subspecies. Domestication may have occurred initially in separate areas, particularly Siberia and Europe. Currently it is thought domestication of our current lineage of dog occurred sometime as early as 15,000 years ago and arguably as late as 8500 years ago. Shortly after the latest domestication, dogs became ubiquitous in human populations, and spread throughout the world.
Emigrants from Siberia likely crossed the Bering Strait with dogs in their company, and some experts suggest the use of sled dogs may have been critical to the success of the waves that entered North America roughly 12,000 years ago, although the earliest archaeological evidence of dog-like canids in North America dates from about 9,400 years ago. Dogs were an important part of life for the Athabascan population in North America, and were their only domesticated animal. Dogs also carried much of the load in the migration of the Apache and Navajo tribes 1,400 years ago. Use of dogs as pack animals in these cultures often persisted after the introduction of the horse to North America.
The current consensus among biologists and archaeologists is that the dating of first domestication is indeterminate, although more recent evidence shows isolated domestication events as early as 33,000 years ago. There is conclusive evidence the present lineage of dogs genetically diverged from their wolf ancestors at least 15,000 years ago, but some believe domestication to have occurred earlier. Evidence is accruing that there were previous domestication events, but that those lineages died out.
It is not known whether humans domesticated the wolf as such to initiate dog's divergence from its ancestors, or whether dog's evolutionary path had already taken a different course prior to domestication. For example, it is hypothesized that some wolves gathered around the campsites of paleolithic camps to scavenge refuse, and associated evolutionary pressure developed that favored those who were less frightened by, and keener in approaching, humans.
The bulk of the scientific evidence for the evolution of the domestic dog stems from morphological studies of archaeological findings andmitochondrial DNA studies. The divergence date of roughly 15,000 years ago is based in part on archaeological evidence that demonstrates the domestication of dogs occurred more than 15,000 years ago, and some genetic evidence indicates the domestication of dogs from their wolf ancestors began in the late Upper Paleolithic close to the Pleistocene/Holocene boundary, between 17,000 and 14,000 years ago. But there is a wide range of other, contradictory findings that make this issue controversial. There are findings beginning currently at 33,000 years ago distinctly placing them as domesticated dogs evidenced not only by shortening of the muzzle but widening as well as crowding of teeth.
Domestic dogs inherited complex behaviors from their wolf ancestors, which would have been pack hunters with complex body language. These sophisticated forms of social cognition and communication may account for their trainability, playfulness, and ability to fit into human households and social situations, and these attributes have given dogs a relationship with humans that has enabled them to become one of the most successful species on the planet today.
Although experts largely disagree over the details of dog domestication, it is agreed that human interaction played a significant role in shaping the subspecies. Domestication may have occurred initially in separate areas, particularly Siberia and Europe. Currently it is thought domestication of our current lineage of dog occurred sometime as early as 15,000 years ago and arguably as late as 8500 years ago. Shortly after the latest domestication, dogs became ubiquitous in human populations, and spread throughout the world.
Emigrants from Siberia likely crossed the Bering Strait with dogs in their company, and some experts suggest the use of sled dogs may have been critical to the success of the waves that entered North America roughly 12,000 years ago, although the earliest archaeological evidence of dog-like canids in North America dates from about 9,400 years ago. Dogs were an important part of life for the Athabascan population in North America, and were their only domesticated animal. Dogs also carried much of the load in the migration of the Apache and Navajo tribes 1,400 years ago. Use of dogs as pack animals in these cultures often persisted after the introduction of the horse to North America.
The current consensus among biologists and archaeologists is that the dating of first domestication is indeterminate, although more recent evidence shows isolated domestication events as early as 33,000 years ago. There is conclusive evidence the present lineage of dogs genetically diverged from their wolf ancestors at least 15,000 years ago, but some believe domestication to have occurred earlier. Evidence is accruing that there were previous domestication events, but that those lineages died out.
It is not known whether humans domesticated the wolf as such to initiate dog's divergence from its ancestors, or whether dog's evolutionary path had already taken a different course prior to domestication. For example, it is hypothesized that some wolves gathered around the campsites of paleolithic camps to scavenge refuse, and associated evolutionary pressure developed that favored those who were less frightened by, and keener in approaching, humans.
The bulk of the scientific evidence for the evolution of the domestic dog stems from morphological studies of archaeological findings andmitochondrial DNA studies. The divergence date of roughly 15,000 years ago is based in part on archaeological evidence that demonstrates the domestication of dogs occurred more than 15,000 years ago, and some genetic evidence indicates the domestication of dogs from their wolf ancestors began in the late Upper Paleolithic close to the Pleistocene/Holocene boundary, between 17,000 and 14,000 years ago. But there is a wide range of other, contradictory findings that make this issue controversial. There are findings beginning currently at 33,000 years ago distinctly placing them as domesticated dogs evidenced not only by shortening of the muzzle but widening as well as crowding of teeth.
Tesem, an old Egyptian sighthound-like dog. Archaeological evidence suggests that the latest point at which dogs could have diverged from wolves was roughly 15,000 years ago, although it is possible they diverged much earlier. In 2008, a team of international scientists released findings from an excavation at Goyet Cave in Belgium declaring a large, toothy canine existed 31,700 years ago and ate a diet of horse, musk ox and reindeer.
Prior to this Belgian discovery, the earliest dog bones found were two large skulls from Russia and a mandible from Germany dated from roughly 14,000 years ago. Remains of smaller dogs from Natufian cave deposits in the Middle East, including the earliest burial of a human being with a domestic dog, have been dated to around 10,000 to 12,000 years ago. There is a great deal of archaeological evidence for dogs throughout Europe and Asia around this period and through the next two thousand years (roughly 8,000 to 10,000 years ago), with specimens uncovered in Germany, the French Alps, and Iraq, and cave paintings in Turkey. The oldest remains of a domesticated dog in the Americas were found in Texas and have been dated to about 9,400 years ago.
Prior to this Belgian discovery, the earliest dog bones found were two large skulls from Russia and a mandible from Germany dated from roughly 14,000 years ago. Remains of smaller dogs from Natufian cave deposits in the Middle East, including the earliest burial of a human being with a domestic dog, have been dated to around 10,000 to 12,000 years ago. There is a great deal of archaeological evidence for dogs throughout Europe and Asia around this period and through the next two thousand years (roughly 8,000 to 10,000 years ago), with specimens uncovered in Germany, the French Alps, and Iraq, and cave paintings in Turkey. The oldest remains of a domesticated dog in the Americas were found in Texas and have been dated to about 9,400 years ago.