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Dog: the story on HearLore | HearLore
Dog
The earliest known dog, buried in Bonn-Oberkassel, Germany, was not a pet but a companion in death, interred with a man and a woman under thick basalt blocks and covered in red hematite powder 14,223 years ago. This burial predates the development of agriculture by thousands of years, marking the dog as the first species to be domesticated by hunter-gatherers. The dog had survived canine distemper as a puppy, an illness that would have been fatal without intensive human care, suggesting a bond that existed before the dog could perform any utilitarian work. Genetic studies indicate that the domestication process began over 25,000 years ago, likely in Siberia, where ancient North Siberians domesticated wolves before dispersing eastward into the Americas and westward across Eurasia. This ancient lineage diverged from an extinct wolf population, distinct from any modern wolf lineage, creating a unique genetic bridge between the wild canids and the domesticated companions that now number between 700 million and 1 billion globally.
The Genetic Blueprint of Tameness
A 2018 study identified 429 genes that differ between modern dogs and modern wolves, revealing that the initial selection during domestication was for behavior rather than physical appearance. These genes are linked to neural crest and central nervous system development, affecting embryogenesis to confer tameness, smaller jaws, floppy ears, and diminished craniofacial development, a phenomenon known as domestication syndrome. While wolves retain a strong fight-or-flight response, dogs have evolved to be less timid and less aggressive, with traits of high sociability and lack of fear that may be genetically modified to resemble Williams-Beuren syndrome in humans. This hypersociability comes at the expense of some problem-solving abilities, as evidenced by studies showing that Australian dingos can outperform domestic dogs in non-social problem-solving tasks. The dog's brain is dominated by a large olfactory cortex rather than a visual cortex, and they possess roughly forty times more smell-sensitive receptors than humans, allowing them to detect chemical changes in the environment with unparalleled precision.
The Great Divide of Breeds
There are around 450 official dog breeds, the most of any mammal, displaying more phenotypic diversity in skull, body, and limb proportions than can be found within the entire order of carnivores. This rapid diversification occurred during the Victorian era when humans took control of natural selection, deriving most breeds from small numbers of founders within the last 200 years. The skeletal structure of a dog remains consistent in bone count regardless of size, yet the Great Dane stands at over 30 inches tall while the Chihuahua measures just 6 inches, and dwarfism has been selectively bred into breeds like dachshunds and corgis. The skull shapes vary from the elongated dolichocephalic type of sighthounds to the very short and broad brachycephalic type of mastiffs, each adapted for specific roles ranging from hunting and herding to guarding and retrieving. This artificial selection has created distinct traits in morphology, behavior, and personality, allowing dogs to fulfill specific work or roles that have defined human society for millennia.
When was the earliest known dog buried in Bonn-Oberkassel, Germany?
The earliest known dog was buried 14,223 years ago under thick basalt blocks and covered in red hematite powder. This burial predates the development of agriculture by thousands of years and marks the dog as the first species to be domesticated by hunter-gatherers.
Where did the domestication of dogs begin according to genetic studies?
Genetic studies indicate that the domestication process began over 25,000 years ago likely in Siberia. Ancient North Siberians domesticated wolves before dispersing eastward into the Americas and westward across Eurasia.
How many official dog breeds exist and when did most diversification occur?
There are around 450 official dog breeds the most of any mammal. This rapid diversification occurred during the Victorian era when humans took control of natural selection deriving most breeds from small numbers of founders within the last 200 years.
What percentage of global rabies deaths were caused by dogs in 2018?
In 2018 the World Health Organization reported that 59,000 people died globally from rabies with 59.6% of the deaths in Asia and 36.4% in Africa. Dogs are the most significant vector for this disease.
Which dog became the first animal launched into Earth orbit in 1957?
In 1957 the dog Laika became one of the first animals to be launched into Earth orbit aboard the Soviets's Sputnik 2. She died during the flight from overheating.
Dogs perceive the world through a dichromatic vision consisting of yellows, blues, and grays, with visual acuity up to eight times less effective than that of humans, yet they possess an acute sense of hearing up to four times greater than humans. They can pick up the slightest sounds from about 40 feet away, compared to 20 feet for humans, and their stiff, deeply embedded whiskers sense atmospheric changes and vibrations to alert them of objects that could collide with their nose, ears, and jaw. While their vision is limited, their sense of smell is the most prominent sense of the species, detecting chemical changes that allow them to pinpoint the location of mating partners, potential stressors, and resources. Dogs also exhibit magnetoreception, preferring to defecate with their spines aligned in a north-south position in calm magnetic field conditions, and they can feel small variations in Earth's magnetic field. This sensory dominance allows them to communicate through eye gaze, facial expression, vocalization, body posture, and chemical signals, marking territories by urinating on them, a behavior more likely when entering a new environment.
The Shadow of the Pack
Feral and free-ranging dogs compete with other large carnivores, yet their strong association with humans limits their potential to dominate ecosystems, though they have made 11 vertebrate species extinct and are identified as a potential threat to at least 188 threatened species worldwide. In New Zealand, dogs have been documented to have killed a few birds of the endangered species, the kagu, and have made 156 animal species extinct, while in the Amur river region, Siberian tigers have killed dogs in the middle of villages. Wolves, known to kill dogs, tend to live in pairs in areas where they are highly persecuted, giving them a disadvantage when facing large dog groups, yet there are instances where wolves have displayed uncharacteristic fearlessness of humans and buildings when attacking dogs. The dog's role as an introduced predator has affected the ecology of regions that lacked indigenous land-based mammals before human settlement, creating a complex web of competition and coexistence that spans from the Arctic to the tropics.
The Paradox of Companionship
The keeping of dogs as companions has a long history, with pet-dog populations growing significantly after World War II as suburbanization increased, and the second half of the 20th century saw a major social status shift where more and more dog owners considered their animal to be part of the family. This transformation allowed the dog to conform to social expectations of personality and behavior, leading to the broadening of the concepts of family and the home to include dogs-as-dogs within everyday routines and practices. Products such as dog-training books, classes, and television programs target dog owners, and human family members have increased participation in activities in which the dog is an integral partner, such as dog dancing and dog yoga. Yet, the idea of the alpha dog trying to be dominant is based on a controversial theory about wolf packs, and the scientific evidence regarding the health benefits of dog ownership remains mixed, with some studies showing reduced hospital visits and increased physical activity, while others fail to support earlier findings of reduced cardiovascular disease risk.
The Global Burden of Bites
In 2018, the World Health Organization reported that 59,000 people died globally from rabies, with 59.6% of the deaths in Asia and 36.4% in Africa, and dogs are the most significant vector for this disease. Dog bites affect tens of millions of people globally each year, with children being the primary victims who are more likely to sustain more serious injuries from bites, which can lead to death. In the United States, cats and dogs are a factor in more than 86,000 falls each year, and it has been estimated that around 2% of dog-related injuries treated in U.K. hospitals are domestic accidents. Toxocara canis eggs in dog feces can cause toxocariasis, with nearly 14% of people in the United States infected, and dog feces can also contain hookworms that cause cutaneous larva migrans in humans. Despite these risks, dogs have been used as police dogs, search and rescue dogs, and detection dogs, and in 1957, the dog Laika became one of the first animals to be launched into Earth orbit aboard the Soviets's Sputnik 2, though she died during the flight from overheating.
The Cultural Mirror of Humanity
Artworks have depicted dogs as symbols of guidance, protection, loyalty, fidelity, faithfulness, alertness, and love, appearing in ancient Mesopotamia as the symbol of Ninisina, the goddess of healing and medicine, and in Greek mythology as Cerberus, the three-headed, dragon-tailed watchdog who guards the gates of Hades. In Norse mythology, a dog called Garmr guards Hel, a realm of the dead, and in Persian mythology, two four-eyed dogs guard the Chinvat Bridge, while in Hindu mythology, Yama, the god of death, owns two watchdogs named Shyama and Sharvara. In Christianity, dogs represent faithfulness, and within the Roman Catholic denomination, the iconography of Saint Dominic includes a dog after the saint's mother dreamt of a dog springing from her womb. Yet, the view on dogs in Islam is mixed, with some schools of thought viewing them as unclean, and in some parts of the world, eating dog meat is a social taboo, though it is still consumed in some East Asian countries, including China, Vietnam, Korea, Indonesia, and the Philippines, with an estimated 30 million dogs killed and consumed in Asia every year.