The breed with the shortest lifespan (among breeds for which there is a questionnaire survey with a reasonable sample size) is the Dogue de Bordeaux, with a median longevity of about 5.2 years, but several breeds, including miniature bull terriers, bloodhounds, and Irish wolfhounds are nearly as short-lived, with median longevities of 6 to 7 years.[64]

In 1758, the Swedish botanist and zoologist Carl Linnaeus published in his Systema Naturae the binomial nomenclature – or the two-word naming – of species. Canis is the Latin word meaning "dog",[21] and under this genus he listed the dog-like carnivores including domestic dogs, wolves, and jackals. He classified the domestic dog as Canis familiaris, and on the next page he classified the wolf as Canis lupus.[3] Linnaeus considered the dog to be a separate species from the wolf because of its cauda recurvata - its upturning tail which is not found in any other canid.[22]
Neutering reduces problems caused by hypersexuality, especially in male dogs.[76] Spayed female dogs are less likely to develop some forms of cancer, affecting mammary glands, ovaries, and other reproductive organs.[77] However, neutering increases the risk of urinary incontinence in female dogs,[78] and prostate cancer in males,[79] as well as osteosarcoma, hemangiosarcoma, cruciate ligament rupture, obesity, and diabetes mellitus in either sex.[80]

Every year, between 6 and 8 million dogs and cats enter US animal shelters.[204] The Humane Society of the United States (HSUS) estimates that approximately 3 to 4 million of those dogs and cats are euthanized yearly in the United States.[205] However, the percentage of dogs in US animal shelters that are eventually adopted and removed from the shelters by their new legal owners has increased since the mid-1990s from around 25% to a 2012 average of 40% among reporting shelters[206] (with many shelters reporting 60–75%).[207]


The most popular Korean dog dish is gaejang-guk (also called bosintang), a spicy stew meant to balance the body's heat during the summer months. Followers of the custom claim this is done to ensure good health by balancing one's gi, or vital energy of the body. A 19th century version of gaejang-guk explains that the dish is prepared by boiling dog meat with scallions and chili powder. Variations of the dish contain chicken and bamboo shoots. While the dishes are still popular in Korea with a segment of the population, dog is not as widely consumed as beef, chicken, and pork.[174]
Clip the dog's hair methodically.[9] You can place the blade against the body safely, so long as you don't press the blade strongly into the skin. Brush against the direction of hair growth(back-brush) before running the clippers the other direction; with the direction of hair growth. Using the clippers against the growth of hair will have the same effect as back-brushing, but will leave a shorter length than the clipper blade that you are using. If you want to shave against the growth of hair, a blade size gets two blade sizes smaller when cutting against the grain. For example, when cutting with 4# against the grain check how long a 7# leaves behind when cutting with the grain. Move the clippers surely, but slowly across the dog's body to remove the hair — moving too fast might leave uneven lines. Always move the blade with the direction of the hairs' growth unless you want a shorter length than your blade claims to leave. Begin at the neck, then move down to the shoulders, under the ears, and toward the chin, throat, and chest areas. DO NOT use a size seven or any skip blades around the throat area or any flaps on the body that can fit between the teeth, such as the Achilles' tendons, arm pits, genital area, tip of tail, or anus. Then, clip the dog's back and sides. Finally, clip the hair on the dog's legs. Be careful when cutting the neck with any blade as it's the most dangerous to cut. Never cut straight down, do so at angles to avoid flaps you can't see in the neck getting cut.
Their long association with humans has led dogs to be uniquely attuned to human behavior[18] and they are able to thrive on a starch-rich diet that would be inadequate for other canid species.[19] Dogs vary widely in shape, size and colors.[20] They perform many roles for humans, such as hunting, herding, pulling loads, protection, assisting police and military, companionship and, more recently, aiding disabled people and therapeutic roles. This influence on human society has given them the sobriquet of "man's best friend".

The genetic divergence between dogs and wolves occurred between 40,000–20,000 years ago, just before or during the Last Glacial Maximum.[27][2] This timespan represents the upper time-limit for the commencement of domestication because it is the time of divergence and not the time of domestication, which occurred later.[27][28] The domestication of animals commenced over 15,000 years ago, beginning with the grey wolf (Canis lupus) by nomadic hunter-gatherers.[27] The archaeological record and genetic analysis show the remains of the Bonn–Oberkassel dog buried beside humans 14,200 years ago to be the first undisputed dog, with disputed remains occurring 36,000 years ago.[2] It was not until 11,000 years ago that people living in the Near East entered into relationships with wild populations of aurochs, boar, sheep, and goats.[27]
African village dogs Bandogs Bichons Bulldogs Crossbreed dogs Curs Dogos Feists Fighting dogs Pit bulls Guard dogs Gun dogs Pointers Retrievers Setters Water dogs Hairless dogs Hounds Scenthounds Sighthounds Laika Lap dogs Mastiffs Mongrels Mountain dogs Molossers Meat dogs Pastoral dogs Herding dogs Livestock guardian dogs Pinschers Purebred dogs Sled dogs Schnauzers Spaniels Spitz Street dogs Terriers Toy dogs Turnspit dogs Wolfdogs

Dog behavior is the internally coordinated responses (actions or inactions) of the domestic dog (individuals or groups) to internal and/or external stimuli.[94] As the oldest domesticated species, with estimates ranging from 9,000–30,000 years BCE, the minds of dogs inevitably have been shaped by millennia of contact with humans. As a result of this physical and social evolution, dogs, more than any other species, have acquired the ability to understand and communicate with humans, and they are uniquely attuned to human behaviors.[18] Behavioral scientists have uncovered a surprising set of social-cognitive abilities in the domestic dog. These abilities are not possessed by the dog's closest canine relatives nor by other highly intelligent mammals such as great apes but rather parallel some of the social-cognitive skills of human children.[95]
The role of the dog in Chinese mythology includes a position as one of the twelve animals which cyclically represent years (the zodiacal dog). Three of the 88 constellations in western astronomy also represent dogs: Canis Major (the Great Dog, whose brightest star, Sirius, is also called the Dog Star), Canis Minor (the Little Dog), and Canes Venatici (the Hunting Dogs).
This article was co-authored by Pippa Elliott, MRCVS. Dr. Elliott, BVMS, MRCVS is a veterinarian with over 30 years of experience in veterinary surgery and companion animal practice. She graduated from the University of Glasgow in 1987 with a degree in veterinary medicine and surgery. She has worked at the same animal clinic in her hometown for over 20 years.
Despite their close genetic relationship and the ability to inter-breed, there are a number of diagnostic features to distinguish the gray wolves from domestic dogs. Domesticated dogs are clearly distinguishable from wolves by starch gel electrophoresis of red blood cell acid phosphatase.[41] The tympanic bullae are large, convex and almost spherical in gray wolves, while the bullae of dogs are smaller, compressed and slightly crumpled.[42] Compared with equally sized wolves, dogs tend to have 20% smaller skulls and 30% smaller brains.[43]:35 The teeth of gray wolves are also proportionately larger than those of dogs.[44] Dogs have a more domed forehead and a distinctive "stop" between forehead and nose.[45] The temporalis muscle that closes the jaws is more robust in wolves.[5]:p158 Wolves do not have dewclaws on their back legs, unless there has been admixture with dogs that had them.[46] Most dogs lack a functioning pre-caudal gland and enter estrus twice yearly, unlike gray wolves which only do so once a year.[47] So-called primitive dogs such as dingoes and Basenjis retain the yearly estrus cycle.[48]

Neutering reduces problems caused by hypersexuality, especially in male dogs.[76] Spayed female dogs are less likely to develop some forms of cancer, affecting mammary glands, ovaries, and other reproductive organs.[77] However, neutering increases the risk of urinary incontinence in female dogs,[78] and prostate cancer in males,[79] as well as osteosarcoma, hemangiosarcoma, cruciate ligament rupture, obesity, and diabetes mellitus in either sex.[80]
In mythology, dogs often serve as pets or as watchdogs.[208] Stories of dogs guarding the gates of the underworld recur throughout Indo-European mythologies[210][211] and may originate from Proto-Indo-European religion.[210][211] In Greek mythology, Cerberus is a three-headed watchdog who guards the gates of Hades.[208] In Norse mythology, a bloody, four-eyed dog called Garmr guards Helheim.[208] In Persian mythology, two four-eyed dogs guard the Chinvat Bridge.[208] In Welsh mythology, Annwn is guarded by Cŵn Annwn.[208] In Hindu mythology, Yama, the god of death, owns two watch dogs who have four eyes. They are said to watch over the gates of Naraka.[212]
Citing a 2008 study, the U.S. Center for Disease Control estimated in 2015 that 4.5 million people in the USA are bitten by dogs each year.[176] A 2015 study estimated that 1.8% of the U.S. population is bitten each year.[177] In the 1980s and 1990s the US averaged 17 fatalities per year, while since 2007 this has increased to an average of 31.[178] 77% of dog bites are from the pet of family or friends, and 50% of attacks occur on the property of the dog's legal owner.[178]
Dogs have lived and worked with humans in many roles. In addition to dogs' role as companion animals, dogs have been bred for herding livestock (collies, sheepdogs),[154][17] hunting (hounds, pointers),[43] and rodent control (terriers).[17] Other types of working dogs include search and rescue dogs,[155] detection dogs trained to detect illicit drugs[156] or chemical weapons;[157] guard dogs; dogs who assist fishermen with the use of nets; and dogs that pull loads.[17] In 1957, the dog Laika became the first animal to be launched into Earth orbit, aboard the Soviets' Sputnik 2; she died during the flight.[158][159]
In 1758, the Swedish botanist and zoologist Carl Linnaeus published in his Systema Naturae the binomial nomenclature – or the two-word naming – of species. Canis is the Latin word meaning "dog",[21] and under this genus he listed the dog-like carnivores including domestic dogs, wolves, and jackals. He classified the domestic dog as Canis familiaris, and on the next page he classified the wolf as Canis lupus.[3] Linnaeus considered the dog to be a separate species from the wolf because of its cauda recurvata - its upturning tail which is not found in any other canid.[22]
The domestic dog (Canis lupus familiaris when considered a subspecies of the wolf or Canis familiaris when considered a distinct species)[5] is a member of the genus Canis (canines), which forms part of the wolf-like canids,[6] and is the most widely abundant terrestrial carnivore.[7][8][9][10][11] The dog and the extant gray wolf are sister taxa[12][13][14] as modern wolves are not closely related to the wolves that were first domesticated,[13][14] which implies that the direct ancestor of the dog is extinct.[15] The dog was the first species to be domesticated[14][16] and has been selectively bred over millennia for various behaviors, sensory capabilities, and physical attributes.[17]

Toxocara canis (dog roundworm) eggs in dog feces can cause toxocariasis. In the United States, about 10,000 cases of Toxocara infection are reported in humans each year, and almost 14% of the U.S. population is infected.[185] In Great Britain, 24% of soil samples taken from public parks contained T. canis eggs.[186][failed verification] Untreated toxocariasis can cause retinal damage and decreased vision.[186] Dog feces can also contain hookworms that cause cutaneous larva migrans in humans.[187][188][189][190]
Some breeds of dogs are prone to certain genetic ailments such as elbow and hip dysplasia, blindness, deafness, pulmonic stenosis, cleft palate, and trick knees. Two serious medical conditions particularly affecting dogs are pyometra, affecting unspayed females of all types and ages, and gastric dilatation volvulus (bloat), which affects the larger breeds or deep-chested dogs. Both of these are acute conditions, and can kill rapidly. Dogs are also susceptible to parasites such as fleas, ticks, mites, hookworms, tapeworms, roundworms, and heartworms (roundworm species that lives in the heart of dogs).
A common breeding practice for pet dogs is mating between close relatives (e.g. between half- and full siblings).[81] Inbreeding depression is considered to be due largely to the expression of homozygous deleterious recessive mutations.[82] Outcrossing between unrelated individuals, including dogs of different breeds, results in the beneficial masking of deleterious recessive mutations in progeny.[83]
Their long association with humans has led dogs to be uniquely attuned to human behavior[18] and they are able to thrive on a starch-rich diet that would be inadequate for other canid species.[19] Dogs vary widely in shape, size and colors.[20] They perform many roles for humans, such as hunting, herding, pulling loads, protection, assisting police and military, companionship and, more recently, aiding disabled people and therapeutic roles. This influence on human society has given them the sobriquet of "man's best friend".
Unlike other domestic species which were primarily selected for production-related traits, dogs were initially selected for their behaviors.[96][97] In 2016, a study found that there were only 11 fixed genes that showed variation between wolves and dogs. These gene variations were unlikely to have been the result of natural evolution, and indicate selection on both morphology and behavior during dog domestication. These genes have been shown to affect the catecholamine synthesis pathway, with the majority of the genes affecting the fight-or-flight response[97][98] (i.e. selection for tameness), and emotional processing.[97] Dogs generally show reduced fear and aggression compared with wolves.[97][99] Some of these genes have been associated with aggression in some dog breeds, indicating their importance in both the initial domestication and then later in breed formation.[97] Traits of high sociability and lack of fear in dogs may include genetic modifications related to Williams-Beuren syndrome in humans, which cause hypersociability at the expense of problem solving ability.[100][101][102]
^ Fan, Zhenxin; Silva, Pedro; Gronau, Ilan; Wang, Shuoguo; Armero, Aitor Serres; Schweizer, Rena M.; Ramirez, Oscar; Pollinger, John; Galaverni, Marco; Ortega Del-Vecchyo, Diego; Du, Lianming; Zhang, Wenping; Zhang, Zhihe; Xing, Jinchuan; Vilà, Carles; Marques-Bonet, Tomas; Godinho, Raquel; Yue, Bisong; Wayne, Robert K. (2016). "Worldwide patterns of genomic variation and admixture in gray wolves". Genome Research. 26 (2): 163–173. doi:10.1101/gr.197517.115. PMC 4728369. PMID 26680994.

Experienced pet stylists hired from outside the company must complete a personal skill evaluation by a Petco Certified Pet Stylist or Grooming Salon Leader, as well as four weeks of safety and pet grooming operations training. They must also complete and pass a technical skills assessment within 14 days of hire. If the candidate does not pass the technical evaluations, they must complete Petco's 12-week Pet Stylist Apprentice & Certification program and retake the skills assessment.
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