The dog (''Canis familiaris''
[ or ''Canis lupus familiaris'') is a ]domesticated
Domestication is a sustained multi-generational relationship in which humans assume a significant degree of control over the reproduction and care of another group of organisms to secure a more predictable supply of resources from that group. A ...
descendant of the wolf
The wolf (''Canis lupus''; : wolves), also known as the gray wolf or grey wolf, is a large canine native to Eurasia and North America. More than thirty subspecies of ''Canis lupus'' have been recognized, and gray wolves, as popularly un ...
. Also called the domestic dog, it is derived from the extinct Pleistocene wolf
The Pleistocene wolf, also referred to as the Late Pleistocene wolf, is an extinct lineage or ecomorph of the gray wolf (''Canis lupus''). It was a Late Pleistocene – early Holocene hypercarnivore. While comparable in size to a large modern ...
,[ and the modern ]wolf
The wolf (''Canis lupus''; : wolves), also known as the gray wolf or grey wolf, is a large canine native to Eurasia and North America. More than thirty subspecies of ''Canis lupus'' have been recognized, and gray wolves, as popularly un ...
is the dog's nearest living relative.[ Dogs were the first ]species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
to be domesticated[ by hunter-gatherers over 15,000 years ago][ before the development of agriculture.][ Due to their long association with humans, dogs have expanded to a large number of domestic individuals] and gained the ability to thrive on a starch-rich diet that would be inadequate for other canids
Canidae (; from Latin, ''canis'', " dog") is a biological family of dog-like carnivorans, colloquially referred to as dogs, and constitutes a clade. A member of this family is also called a canid (). There are three subfamilies found within ...
.
The dog has been selectively bred
Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant m ...
over millennia for various behaviors, sensory capabilities, and physical attributes. Dog breed
A dog breed is a particular strain of dog that was purposefully bred by humans to perform specific tasks, such as herding, hunting, and guarding. Dogs are the most variable mammal on Earth, with artificial selection producing around 450 globall ...
s vary widely in shape, size, and color. They perform many roles for humans, such as hunting
Hunting is the human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products ( fur/ hide, bone/tusks, horn/antler, ...
, herding
Herding is the act of bringing individual animals together into a group (herd), maintaining the group, and moving the group from place to place—or any combination of those. Herding can refer either to the process of animals forming herds in ...
, pulling loads, protection
Protection is any measure taken to guard a thing against damage caused by outside forces. Protection can be provided to physical objects, including organisms, to systems, and to intangible things like civil and political rights. Although th ...
, assisting police and the military
A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. It is typically authorized and maintained by a sovereign state, with its members identifiable by their distinct ...
, companionship
The concept of interpersonal relationship involves social associations, connections, or affiliations between two or more people. Interpersonal relationships vary in their degree of intimacy or self-disclosure, but also in their duration, in t ...
, therapy
A therapy or medical treatment (often abbreviated tx, Tx, or Tx) is the attempted remediation of a health problem, usually following a medical diagnosis.
As a rule, each therapy has indications and contraindications. There are many different ...
, and aiding disabled people. Over the millennia, dogs became uniquely adapted to human behavior, and the human-canine bond has been a topic of frequent study. This influence on human society has given them the sobriquet
A sobriquet ( ), or soubriquet, is a nickname, sometimes assumed, but often given by another, that is descriptive. A sobriquet is distinct from a pseudonym, as it is typically a familiar name used in place of a real name, without the need of expla ...
of "man's best friend
"Man's best friend" is a common phrase used to describe domestic dogs, referring to their millennia-long history of close relations, loyalty, friendship, and companionship with humans. The first recorded use of a related phrase is by Frederick ...
".
Taxonomy
In 1758, the Swedish botanist and zoologist Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...
published in his '' Systema Naturae'', the two-word naming of species (binomial nomenclature
In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...
). ''Canis
''Canis'' is a genus of the Caninae which includes multiple extant species, such as wolves, dogs, coyotes, and golden jackals. Species of this genus are distinguished by their moderate to large size, their massive, well-developed skulls and de ...
'' is the Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
word meaning "dog", and under this genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
, he listed the domestic dog, the wolf
The wolf (''Canis lupus''; : wolves), also known as the gray wolf or grey wolf, is a large canine native to Eurasia and North America. More than thirty subspecies of ''Canis lupus'' have been recognized, and gray wolves, as popularly un ...
, and the golden jackal
The golden jackal (''Canis aureus''), also called common jackal, is a wolf-like canid that is native to Southeast Europe, Southwest Asia, South Asia, and regions of Southeast Asia. The golden jackal's coat varies in color from a pale creamy ...
. He classified the domestic dog as ''Canis familiaris'' and, on the next page, classified the grey wolf as ''Canis lupus''.[ Linnaeus considered the dog to be a separate species from the wolf because of its upturning tail (''cauda recurvata''), which is not found in any other ]canid
Canidae (; from Latin, '' canis'', " dog") is a biological family of dog-like carnivorans, colloquially referred to as dogs, and constitutes a clade. A member of this family is also called a canid (). There are three subfamilies found withi ...
.[
In 1999, a study of mitochondrial DNA (mtDNA) indicated that the domestic dog may have originated from the grey wolf, with the dingo and ]New Guinea singing dog
The New Guinea singing dog or New Guinea Highland dog is an ancient ( basal) lineage of dog found in the New Guinea Highlands, on the island of New Guinea. Once considered to be a separate species in its own right, under the name ''Canis hallst ...
breeds having developed at a time when human communities were more isolated from each other.[ In the third edition of '']Mammal Species of the World
''Mammal Species of the World: A Taxonomic and Geographic Reference'' is a standard reference work in mammalogy giving descriptions and bibliographic data for the known species of mammals. It is now in its third edition, published in late 2005, ...
'' published in 2005, the mammalogist In zoology, mammalogy is the study of mammals – a class of vertebrates with characteristics such as homeothermic metabolism, fur, four-chambered hearts, and complex nervous system
In biology, the nervous system is the highly complex part ...
W. Christopher Wozencraft Wallace Christopher Wozencraft (1954–2007) was an American zoologist, specialising in smaller carnivorous mammals. He was professor of biology at Bethel College (Indiana), and chaired the committee on carnivorous mammals at the International Union ...
listed under the wolf ''Canis lupus'' its wild subspecies and proposed two additional subspecies, which formed the domestic dog clade: ''familiaris'', as named by Linnaeus in 1758 and, ''dingo'' named by Meyer in 1793. Wozencraft included ''hallstromi'' (the New Guinea singing dog) as another name ( junior synonym) for the dingo. Wozencraft referred to the mtDNA study as one of the guides informing his decision.[ Mammalogists have noted the inclusion of ''familiaris'' and ''dingo'' together under the "domestic dog" clade][ with some debating it.][
In 2019, a workshop hosted by the IUCN/Species Survival Commission's Canid Specialist Group considered the dingo and the New Guinea singing dog to be ]feral
A feral () animal or plant is one that lives in the wild but is descended from domesticated individuals. As with an introduced species, the introduction of feral animals or plants to non-native regions may disrupt ecosystems and has, in some ...
''Canis familiaris'' and therefore did not assess them for the IUCN Red List of Threatened Species.[
]
Evolution
The Cretaceous–Paleogene extinction event
The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary extinction) was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With the ...
occurred 65 million years ago and brought an end to the non-avian dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
s and the appearance of the first carnivorans. The name ''carnivoran'' is given to a member of the order Carnivora. Carnivorans possess a common arrangement of teeth called carnassials
Carnassials are paired upper and lower teeth modified in such a way as to allow enlarged and often self-sharpening edges to pass by each other in a shearing manner. This adaptation is found in carnivorans, where the carnassials are the modified f ...
, in which the first lower molar and the last upper premolar possess blade-like enamel crowns
A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, partic ...
that act similar to a pair of shears for cutting meat. This dental arrangement has been modified by adaptation over the past 60 million years for diets composed of meat, for crushing vegetation, or for the loss of the carnassial function altogether as in seals, sea lions, and walruses. Today, not all carnivorans are carnivores
A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other so ...
, such as the insect-eating aardwolf
The aardwolf (''Proteles cristata'') is an insectivorous species of hyena, native to East and Southern Africa. Its name means "earth-wolf" in Afrikaans and Dutch. It is also called maanhaar-jackal (Afrikaans for " mane-jackal"), termite-eat ...
.
The carnivoran ancestors of the dog-like caniforms
Caniformia is a suborder within the order Carnivora consisting of "dog-like" carnivorans. They include dogs (wolves, foxes, etc.), bears, raccoons, and mustelids. The Pinnipedia (seals, walruses and sea lions) are also assigned to this group. ...
and the cat-like feliforms
Feliformia is a suborder within the order Carnivora consisting of "cat-like" carnivorans, including cats (large and small), hyenas, mongooses, viverrids, and related taxa. Feliformia stands in contrast to the other suborder of Carnivora, Canifor ...
began their separate evolutionary paths just after the end of the dinosaurs. The first members of the dog family Canidae appeared 40 million years ago, of which only its subfamily the Caninae
The Caninae, known as canines, are one of three subfamilies found within the canid family. The other two canid subfamilies are the extinct Borophaginae and Hesperocyoninae. The Caninae includes all living canids and their most recent fossil rel ...
survives today in the form of the wolf-like and fox-like canines. Within the Caninae, the first members of genus ''Canis
''Canis'' is a genus of the Caninae which includes multiple extant species, such as wolves, dogs, coyotes, and golden jackals. Species of this genus are distinguished by their moderate to large size, their massive, well-developed skulls and de ...
'' appeared six million years ago, the ancestors of modern domestic dogs, wolves, coyotes
The coyote (''Canis latrans'') is a species of canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecological nich ...
, and golden jackals.
Domestication
The earliest remains generally accepted to be those of a domesticated dog were discovered in Bonn-Oberkassel, Germany. Contextual, isotopic, genetic, and morphological evidence shows that this dog was not a local wolf.[ The dog was dated to 14,223 years ago and was found buried along with a man and a woman, all three having been sprayed with red hematite powder and buried under large, thick basalt blocks. The dog had died of ]canine distemper
Canine distemper virus (CDV) (sometimes termed footpad disease) is a viral disease that affects a wide variety of mammal families, including domestic and wild species of dogs, coyotes, foxes, pandas, wolves, ferrets, skunks, raccoons, and felin ...
.[ Earlier remains dating back to 30,000 years ago have been described as Paleolithic dogs, but their status as dogs or wolves remains debated][ because considerable morphological diversity existed among wolves during the Late Pleistocene.][
This timing indicates that the dog was the first species to be domesticated][ in the time of ]hunter–gatherers
A traditional hunter-gatherer or forager is a human living an ancestrally derived lifestyle in which most or all food is obtained by foraging, that is, by gathering food from local sources, especially edible wild plants but also insects, fungi, ...
,[ which predates agriculture.][ ]DNA sequences
A nucleic acid sequence is a succession of bases signified by a series of a set of five different letters that indicate the order of nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. By convention, sequences are us ...
show that all ancient and modern dogs share a common ancestry and descended from an ancient, extinct wolf population which was distinct from the modern wolf lineage.[ Most dogs form a sister group to the remains of a Late ]Pleistocene wolf
The Pleistocene wolf, also referred to as the Late Pleistocene wolf, is an extinct lineage or ecomorph of the gray wolf (''Canis lupus''). It was a Late Pleistocene – early Holocene hypercarnivore. While comparable in size to a large modern ...
found in the Kessleroch cave near Thayngen
Thayngen () is a village and a municipality in the canton of Schaffhausen in Switzerland. On 1 January 2009 Altdorf, Bibern, Hofen, Opfertshofen merged into Thayngen.[Schaffhausen
Schaffhausen (; gsw, Schafuuse; french: Schaffhouse; it, Sciaffusa; rm, Schaffusa; en, Shaffhouse) is a town with historic roots, a municipality in northern Switzerland, and the capital of the canton of the same name; it has an estimate ...]
, Switzerland, which dates to 14,500 years ago. The most recent common ancestor
In biology and genetic genealogy, the most recent common ancestor (MRCA), also known as the last common ancestor (LCA) or concestor, of a set of organisms is the most recent individual from which all the organisms of the set are descended. The ...
of both is estimated to be from 32,100 years ago.[ This indicates that an extinct Late Pleistocene wolf may have been the ancestor of the dog,][ with the modern wolf being the dog's nearest living relative.][
The dog is a classic example of a domestic animal that likely travelled a ]commensal
Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit fro ...
pathway into domestication.[ The questions of when and where dogs were first domesticated have taxed geneticists and archaeologists for decades.][ 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.][ In 2021, a ]literature review
A literature review is an overview of the previously published works on a topic. The term can refer to a full scholarly paper or a section of a scholarly work such as a book, or an article. Either way, a literature review is supposed to provid ...
of the current evidence infers that the dog was domesticated in Siberia
Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive region, geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a ...
23,000 years ago by ancient North Siberians, then later dispersed eastward into the Americas and westward across Eurasia.[
]
Breeds
Dogs are the most variable mammal on earth with around 450 globally recognized dog breeds
This list of dog breeds includes both extant and extinct dog breeds, varieties, landraces, and dog types. A research article on dog genomics published in Science/AAAS defines modern dog breeds as "a recent invention defined by conformation to ...
.[ In the ]Victorian era
In the history of the United Kingdom and the British Empire, the Victorian era was the period of Queen Victoria's reign, from 20 June 1837 until her death on 22 January 1901. The era followed the Georgian period and preceded the Edwardia ...
, directed human selection
Selection may refer to:
Science
* Selection (biology), also called natural selection, selection in evolution
** Sex selection, in genetics
** Mate selection, in mating
** Sexual selection in humans, in human sexuality
** Human mating strateg ...
developed the modern dog breeds
This list of dog breeds includes both extant and extinct dog breeds, varieties, landraces, and dog types. A research article on dog genomics published in Science/AAAS defines modern dog breeds as "a recent invention defined by conformation to ...
, which resulted in a vast range of phenotypes.[ Most breeds were derived from small numbers of founders within the last 200 years,][ and since then dogs have undergone rapid ]phenotypic
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological proper ...
change and were formed into today's modern breeds due to artificial selection imposed by humans. The skull, body, and limb proportions vary significantly between breeds, with dogs displaying more phenotypic diversity than can be found within the entire order of carnivores. These breeds possess distinct traits related to morphology, which include body size, skull shape, tail phenotype, fur type and colour.[ Their behavioural traits include guarding, herding, and hunting,][ retrieving, and scent detection. Their personality traits include hypersocial behavior, boldness, and aggression,][ which demonstrates the functional and behavioral diversity of dogs.][ As a result, present day dogs are the most abundant carnivore species and are dispersed around the world.][ The most striking example of this dispersal is that of the numerous modern breeds of European lineage during the Victorian era.][
]
Biology
Anatomy
Skeleton
All healthy dogs, regardless of their size and type, have an identical skeletal structure with the exception of the number of bones in the tail, although there is significant skeletal variation between dogs of different types. The dog's skeleton is well adapted for running; the vertebra
The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristi ...
e on the neck and back have extensions for powerful back muscles to connect to, the long ribs provide plenty of room for the heart and lungs, and the shoulders are unattached to the skeleton allowing great flexibility.
Compared to the dog's wolf-like ancestors, selective breeding since domestication has seen the dog's skeleton greatly enhanced in size for larger types as mastiff
A mastiff is a large and powerful type of dog. Mastiffs are among the largest dogs, and typically have a short coat, a long low-set tail and large feet; the skull is large and bulky, the muzzle broad and short ( brachycephalic) and the ears dr ...
s and miniaturised for smaller types such as terrier
Terrier (from Latin ''terra'', 'earth') is a type of dog originally bred to hunt vermin. A terrier is a dog of any one of many breeds or landraces of the terrier type, which are typically small, wiry, game, and fearless. Terrier breeds vary ...
s; dwarfism has been selectively utilised for some types where short legs are advantageous such as dachshunds and corgi
The Welsh Corgi ( or Corgi, plural Corgis, or occasionally the etymologically consistent Corgwn; ) is a small type of herding dog that originated in Wales. The name ''corgi'' is derived from the Welsh words and (which is mutated to ), mean ...
s. Most dogs naturally have 26 vertebrae in their tails, but some with naturally short tails have as few as three.
The dog's skull has identical components regardless of breed type, but there is significant divergence in terms of skull shape between types. The three basic skull shapes are the elongated dolichocephalic type as seen in sighthounds, the intermediate mesocephalic or mesaticephalic type, and the very short and broad brachycephalic type exemplified by mastiff type skulls.
Senses
A dog's senses include vision, hearing, smell, taste, touch, and sensitivity to Earth's magnetic field. Another study has suggested that dogs can see Earth's magnetic field.
Coat
The coats of domestic dogs are of two varieties: "double" being familiar with dogs (as well as wolves) originating from colder climates, made up of a coarse guard hair
Guard hair or overhair is the outer layer of hair of most mammals, which overlay the fur. Guard hairs are long and coarse and protect the rest of the pelage (fur) from abrasion and frequently from moisture. They are visible on the surface of the fu ...
and a soft down hair
Fur is a thick growth of hair that covers the skin of mammals. It consists of a combination of oily guard hair on top and thick underfur beneath. The guard hair keeps moisture from reaching the skin; the underfur acts as an insulating blanket ...
, or "single", with the topcoat only. Breeds may have an occasional "blaze", stripe, or "star" of white fur on their chest or underside. Premature graying can occur in dogs from as early as one year of age; this is associated with impulsive behavior
In psychology, impulsivity (or impulsiveness) is a tendency to act on a whim, displaying behavior characterized by little or no forethought, reflection, or consideration of the consequences. Impulsive actions are typically "poorly conceived, pre ...
s, anxiety behaviors, fear of noise, and fear of unfamiliar people or animals.
Tail
There are many different shapes for dog tails: straight, straight up, sickle, curled, or corkscrew. As with many canids, one of the primary functions of a dog's tail is to communicate their emotional state, which can be crucial in getting along with others. In some hunting dogs the tail is traditionally docked to avoid injuries.
Health
Some breeds of dogs are prone to specific genetic ailments such as elbow
The elbow is the region between the arm and the forearm that surrounds the elbow joint. The elbow includes prominent landmarks such as the olecranon, the cubital fossa (also called the chelidon, or the elbow pit), and the lateral and the me ...
and hip dysplasia
Hip dysplasia is an abnormality of the hip joint where the socket portion does not fully cover the ball portion, resulting in an increased risk for joint dislocation. Hip dysplasia may occur at birth or develop in early life. Regardless, it doe ...
, blindness
Visual impairment, also known as vision impairment, is a medical definition primarily measured based on an individual's better eye visual acuity; in the absence of treatment such as correctable eyewear, assistive devices, and medical treatment ...
, deafness
Deafness has varying definitions in cultural and medical contexts. In medical contexts, the meaning of deafness is hearing loss that precludes a person from understanding spoken language, an audiological condition. In this context it is written ...
, pulmonic stenosis
Pulmonic stenosis, is a dynamic or fixed obstruction of flow from the right ventricle of the heart to the pulmonary artery. It is usually first diagnosed in childhood. Signs and symptoms
Cause
Pulmonic stenosis is usually due to isolated valvula ...
, cleft palate
A cleft lip contains an opening in the upper lip that may extend into the nose. The opening may be on one side, both sides, or in the middle. A cleft palate occurs when the palate (the roof of the mouth) contains an opening into the nose. The ...
, and trick knees. Two severe medical conditions significantly affecting dogs are pyometra
Pyometra or pyometritis is a uterine infection. Though it is most commonly known as a disease of the unaltered female dog, it is also a notable human disease. It is also seen in female cattle, horses, goats, sheep, swine, cats, rabbits, hamsters, ...
, affecting unspayed females of all breeds and ages, and Gastric dilatation volvulus
Gastric dilatation volvulus (GDV), also known as gastric dilation, twisted stomach, or gastric torsion, is a medical condition that affects dogs in which the stomach becomes overstretched and rotated by excessive gas content. The word bloat is o ...
(bloat), which affects larger breeds or deep-chested dogs. Both of these are acute conditions and can kill rapidly. Dogs are also susceptible to parasites such as flea
Flea, the common name for the order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by ingesting the blood of their hosts. Adult fleas grow to about long, a ...
s, tick
Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by ...
s, mite
Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear e ...
s, hookworms, tapeworm
Eucestoda, commonly referred to as tapeworms, is the larger of the two subclasses of flatworms in the class Cestoda (the other subclass is Cestodaria). Larvae have six posterior hooks on the scolex (head), in contrast to the ten-hooked Cesto ...
s, roundworm
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a bro ...
s, and heartworm
''Dirofilaria immitis'', also known as heartworm or dog heartworm, is a parasitic roundworm that is a type of filarial worm, a small thread-like worm, that causes dirofilariasis. It is spread from host to host through the bites of mosquitoe ...
s, which is a roundworm
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a bro ...
species that lives in the hearts of dogs.
Several human foods and household ingestible are toxic to dogs, including chocolate solids, causing theobromine poisoning
Theobromine poisoning, also informally called chocolate poisoning or cocoa poisoning, is an overdosage reaction to the xanthine alkaloid theobromine, found in chocolate, tea, cola beverages, and some other foods.
Sources
Cocoa powder contains ...
, onion
An onion (''Allium cepa'' L., from Latin ''cepa'' meaning "onion"), also known as the bulb onion or common onion, is a vegetable that is the most widely cultivated species of the genus ''Allium''. The shallot is a botanical variety of the onio ...
s and garlic, causing thiosulphate
Thiosulfate ( IUPAC-recommended spelling; sometimes thiosulphate in British English) is an oxyanion of sulfur with the chemical formula . Thiosulfate also refers to the compounds containing this anion, which are the salts of thiosulfuric acid, e ...
, sulfoxide or disulfide
In biochemistry, a disulfide (or disulphide in British English) refers to a functional group with the structure . The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In ...
poisoning, grape
A grape is a fruit, botanically a berry, of the deciduous woody vines of the flowering plant genus '' Vitis''. Grapes are a non- climacteric type of fruit, generally occurring in clusters.
The cultivation of grapes began perhaps 8,000 years a ...
s and raisin
A raisin is a dried grape. Raisins are produced in many regions of the world and may be eaten raw or used in cooking, baking, and brewing. In the United Kingdom, Ireland, New Zealand, and Australia, the word ''raisin'' is reserved for the ...
s, macadamia nut
''Macadamia'' is a genus of four species of trees in the flowering plant family Proteaceae. They are indigenous to Australia, native to northeastern New South Wales and central and southeastern Queensland specifically. Two species of the genus ...
s, and xylitol
Xylitol is a chemical compound with the formula , or HO(CH2)(CHOH)3(CH2)OH; specifically, one particular stereoisomer with that structural formula. It is a colorless or white crystalline solid that is freely soluble in water. It can be classifi ...
. The nicotine in tobacco can also be dangerous to dogs. Signs of ingestion can include copious vomiting (e.g., from eating cigar butts) or diarrhea
Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin w ...
. Some other symptoms are abdominal pain, loss of coordination, collapse, or death.
Dogs are also vulnerable to some of the same health conditions as humans, including diabetes
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...
, dental and heart disease, epilepsy
Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrica ...
, cancer
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
, hypothyroidism, and arthritis.
Lifespan
The typical lifespan of dogs varies widely among breeds, but for most, the median longevity (the age at which half the dogs in a population have died and half are still alive) ranges from 10 to 13 years. The median longevity of mixed-breed dogs, taken as an average of all sizes, is one or more years longer than that of purebred dogs when all breeds are averaged. For dogs in England, increased body weight has been found to be negatively correlated with longevity (i.e., the heavier the dog, the shorter its lifespan), and mixed-breed dogs live on average 1.2 years longer than purebred dog
A dog breed is a particular strain of dog that was purposefully bred by humans to perform specific tasks, such as herding, hunting, and guarding. Dogs are the most variable mammal on Earth, with artificial selection producing around 450 globall ...
s.[
]
Reproduction
In domestic dogs, sexual maturity
Sexual maturity is the capability of an organism to reproduce. In humans it might be considered synonymous with adulthood, but here puberty is the name for the process of biological sexual maturation, while adulthood is based on cultural definit ...
happens around six months to one year for both males and females, although this can be delayed until up to two years of age for some large breeds, and is the time at which female dogs will have their first estrous cycle
The estrous cycle (, originally ) is the set of recurring physiological changes that are induced by reproductive hormones in most mammalian therian females. Estrous cycles start after sexual maturity in females and are interrupted by anestro ...
. They will experience subsequent estrous cycles semiannually, during which the body prepares for pregnancy
Pregnancy is the time during which one or more offspring develops (gestation, gestates) inside a woman, woman's uterus (womb). A multiple birth, multiple pregnancy involves more than one offspring, such as with twins.
Pregnancy usually occur ...
. At the peak of the cycle, females will become estrous, mentally and physically receptive to copulation
Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal penetra ...
. Because the ova
, abbreviated as OVA and sometimes as OAV (original animation video), are Japanese animated films and series made specially for release in home video formats without prior showings on television or in theaters, though the first part of an OVA s ...
survive and can be fertilized for a week after ovulation, more than one male can sire the same litter.
Fertilization typically occurs two to five days after ovulation; 14–16 days after ovulation, the embryo attaches to the uterus and after seven to eight more days, a heartbeat is detectable.
Dogs bear their litters roughly 58 to 68 days after fertilization
Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Proce ...
, with an average of 63 days, although the length of gestation can vary. An average litter consists of about six puppies
A puppy is a juvenile dog. Some puppies can weigh , while larger ones can weigh up to . All healthy puppies grow quickly after birth. A puppy's coat color may change as the puppy grows older, as is commonly seen in breeds such as the York ...
.
Neutering
Neutering is the sterilization of animals, usually by removing the male's testicles or the female's ovaries
The ovary is an organ in the female reproductive system that produces an ovum. When released, this travels down the fallopian tube into the uterus, where it may become fertilized by a sperm. There is an ovary () found on each side of the body. T ...
and uterus
The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The ...
, to eliminate the ability to procreate and reduce sex drive
Libido (; colloquial: sex drive) is a person's overall sexual drive or desire for sexual activity. Libido is influenced by biological, psychological, and social factors. Biologically, the sex hormones and associated neurotransmitters that act up ...
. Because of dogs' overpopulation in some countries, many animal control agencies, such as the American Society for the Prevention of Cruelty to Animals
The American Society for the Prevention of Cruelty to Animals (ASPCA) is a non-profit organization dedicated to preventing animal cruelty. Based in New York City since its inception in 1866, the organization's mission is "to provide effective me ...
(ASPCA), advise that dogs not intended for further breeding should be neutered, so that they do not have undesired puppies that may later be euthanized.
According to the Humane Society of the United States
The Humane Society of the United States (HSUS) is an American nonprofit organization that focuses on animal welfare and opposes animal-related cruelties of national scope. It uses strategies that are beyond the abilities of local organizations. ...
, three to four million dogs and cats are euthanized
Animal euthanasia ( euthanasia from el, εὐθανασία; "good death") is the act of killing an animal or allowing it to die by withholding extreme medical measures. Reasons for euthanasia include incurable (and especially painful) conditi ...
each year. Many more are confined to cages in shelters because there are many more animals than there are homes. Spaying or castrating dogs helps keep overpopulation down.
Neutering reduces problems caused by hypersexuality
Hypersexuality is extremely frequent or suddenly increased libido. It is controversial whether it should be included as a clinical diagnosis used by mental healthcare professionals. Nymphomania and satyriasis were terms previously used for the c ...
, especially in male dogs. Spayed female dogs are less likely to develop cancers affecting the mammary glands, ovaries, and other reproductive organs. However, neutering increases the risk of urinary incontinence
Urinary incontinence (UI), also known as involuntary urination, is any uncontrolled leakage of urine. It is a common and distressing problem, which may have a large impact on quality of life. It has been identified as an important issue in geri ...
in female dogs and prostate cancer in males and osteosarcoma
An osteosarcoma (OS) or osteogenic sarcoma (OGS) (or simply bone cancer) is a cancerous tumor in a bone. Specifically, it is an aggressive malignant neoplasm that arises from primitive transformed cells of mesenchymal origin (and thus a sarcoma ...
, hemangiosarcoma
Hemangiosarcoma is a rapidly growing, highly invasive variety of cancer that occurs almost exclusively in dogs, and only rarely in cats, horses, mice, or humans (vinyl chloride toxicity). It is a sarcoma arising from the lining of blood vessels; ...
, cruciate ligament
Cruciate ligaments (also cruciform ligaments) are pairs of ligaments arranged like a letter X. They occur in several joints of the body, such as the knee joint and the atlanto-axial joint. In a fashion similar to the cords in a toy Jacob's la ...
rupture, obesity, and diabetes mellitus
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...
in either sex.
Inbreeding depression
A common breeding practice for pet dogs is mating between close relatives (e.g., between half and full siblings). Inbreeding depression
Inbreeding depression is the reduced biological fitness which has the potential to result from inbreeding (the breeding of related individuals). Biological fitness refers to an organism's ability to survive and perpetuate its genetic material. ...
is considered to be due mainly to the expression of homozygous deleterious recessive mutations. Outcrossing between unrelated individuals, including dogs of different breeds, results in the beneficial masking of deleterious recessive mutations in progeny.
In a study of seven dog breeds (the Bernese Mountain Dog
The Bernese Mountain Dog (german: Berner Sennenhund) is a large dog breed, one of the four breeds of Sennenhund- type dogs from Bern, Switzerland and the Swiss Alps. These dogs have roots in the Roman mastiffs. The name ''Sennenhund'' is derived ...
, Basset Hound
The Basset Hound is a short-legged breed of dog in the hound family. The Basset is a scent hound that was originally bred for the purpose of hunting hare. Their sense of smell and ability to ''ground-scent'' is second only to the Bloodhound.Har ...
, Cairn Terrier
The Cairn Terrier is a terrier breed originating in the Scottish Highlands and recognized as one of Scotland's earliest working dogs. The breed was given the name Cairn because the breed's function was to hunt and chase quarry between the ca ...
, Brittany
Brittany (; french: link=no, Bretagne ; br, Breizh, or ; Gallo: ''Bertaèyn'' ) is a peninsula, historical country and cultural area in the west of modern France, covering the western part of what was known as Armorica during the period ...
, German Shepherd Dog, Leonberger
The Leonberger is a dog breed, whose name derives from the city of Leonberg in Baden-Württemberg, Germany.
Description
Appearance
This breed occurs with a generous double coat; the Leonberger is a large, muscular, and elegant dog with balance ...
, and West Highland White Terrier
The West Highland White Terrier, commonly known as the Westie, is a breed of dog from Scotland with a distinctive white harsh coat with a somewhat soft white undercoat. It is a medium-sized terrier, although with longer legs than other Scot ...
), it was found that inbreeding decreases litter size and survival. Another analysis of data on 42,855 Dachshund litters found that as the inbreeding coefficient
The coefficient of inbreeding of an individual is the probability that two alleles at any locus in an individual are identical by descent from the common ancestor(s) of the two parents.
The coefficient of inbreeding is: The probability that two ...
increased, litter size decreased and the percentage of stillborn puppies increased, thus indicating inbreeding depression. In a study of Boxer (dog), Boxer litters, 22% of puppies died before reaching 7 weeks of age. Stillbirth was the most frequent cause of death, followed by infection. Mortality due to infection increased significantly with increases in inbreeding.
Behavior
Dog behavior is the internally coordinated responses (actions or inactions) of the domestic dog (individuals or groups) to internal and external stimuli. As the oldest domesticated species, dogs' minds inevitably have been shaped by millennia of contact with humans. As a result of this physical and social evolution, dogs have acquired the ability to understand and communicate with humans more than any other species and they are uniquely attuned to human behaviors. Behavioral scientists have uncovered a surprising set of social-cognitive abilities in domestic dogs. These abilities are not possessed by the dog's closest canine relatives or other highly intelligent mammals, such as great apes, but rather parallel to children's social-cognitive skills.
Unlike other domestic species selected for production-related traits, dogs were initially selected for their behaviors.[ In 2016, a study found that only 11 fixed genes 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, catecholamine synthesis pathway, with the majority of the genes affecting the fight-or-flight response][ (i.e., selection for tameness) and emotional processing.][ Dogs generally show reduced fear and aggression compared with wolves.][ Some of these genes have been associated with aggression in some dog breeds, indicating their importance in both the initial domestication and later in breed formation.] 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.
Intelligence
Dog intelligence is the dog's ability to perceive information and retain it as knowledge for applying to solve problems. Studies of two dogs suggest that dogs can learn by inference and have advanced memory skills. A study with Rico (Border Collie), Rico, a Border Collie, showed that he knew the labels of over 200 different items. He inferred the names of novel things by exclusion learning and correctly retrieved those new items immediately and four weeks after the initial exposure. A study of another Border Collie, Chaser, documented his learning and memory capabilities. He had learned the names and could associate by verbal command over 1,000 words. Dogs can read and react appropriately to human body language such as gesturing and pointing and human voice commands.
One study of canine cognitive abilities found that dogs' capabilities are no more exceptional than those of other animals, such as horses, Common chimpanzee, chimpanzees, or cats.[ One limited study of 18 household dogs found that they lacked spatial memory, and were more focussed on the "what" of a task rather than the "where".][
Dogs demonstrate a theory of mind by engaging in deception. An experimental study showed compelling evidence that Australian dingos can outperform domestic dogs in non-social problem-solving, indicating that domestic dogs may have lost much of their original problem-solving abilities once they joined humans. Another study revealed that after undergoing training to solve a simple manipulation task, dogs faced with an unsolvable version of the same problem look at the human, while socialized wolves do not.
]
Communication
Dog communication is how dogs convey information to other dogs, understand messages from humans and translate the information that dogs are transmitting. Communication behaviors of dogs include eye gaze, facial expression, vocalization, body posture (including movements of bodies and limbs), and gustatory communication (scents, pheromones, and taste). Humans communicate to dogs by using vocalization, hand signals, and body posture.
Ecology
Population
The dog is probably the most widely abundant large carnivoran living in the human environment.
In 2013, the estimated global dog population was between 700 million and 987 million. About 20% of dogs live as pets in developed countries.[ In the developing world, dogs are typically feral or communally owned, with pet dogs uncommon. Most of these dogs live their lives as scavengers and have never been owned by humans, with one study showing their most common response when approached by strangers is to run away (52%) or respond aggressively (11%). Little is known about these dogs, or the dogs in developed countries that are feral, strays, or are in shelters because the great majority of modern research on dog cognition has focused on pet dogs living in human homes.
]
Competitors and predators
Although dogs are the most abundant and widely distributed terrestrial carnivores, feral and Free-ranging dogs, free-ranging dogs' potential to compete with other large carnivores is limited by their strong association with humans. For example, a review of the studies in dogs' competitive effects on Sympatry, sympatric carnivores did not mention any research on competition between dogs and wolves.[ Although wolves are known to kill dogs, they tend to live in pairs or in small packs in areas where they are highly persecuted, giving them a disadvantage facing large dog groups.][
Wolves kill dogs wherever they are found together. In some instances, wolves have displayed an uncharacteristic fearlessness of humans and buildings when attacking dogs to the extent that they have to be beaten off or killed. Although the numbers of dogs killed each year are relatively low, it induces a fear of wolves entering villages and farmyards to take dogs and losses of dogs to wolves have led to demands for more liberal wolf hunting regulations.][
Coyotes and big cats have also been known to attack dogs. In particular, leopards are known to have a preference for dogs and have been recorded to kill and consume them, no matter what their size.] Siberian tigers in the Amur river, Amur River region have killed dogs in the middle of villages. This indicates that the dogs were targeted. Amur tigers will not tolerate wolves as competitors within their territories, and the tigers could be considering dogs in the same way.[ Striped hyenas are known to kill dogs in their range.]
Diet
Dogs have been described as omnivores. Compared to wolves, dogs from agricultural societies have Amylase#Evolution, extra copies of amylase and other genes involved in starch digestion that contribute to an increased ability to thrive on a starch-rich diet. Similar to humans, some dog breeds produce amylase in their saliva and are classified as having a high starch diet.[
*] However, more like cats and less like other omnivores, dogs can only produce bile acid with taurine and they cannot produce vitamin D, which they obtain from animal flesh. Also more like cats, dogs require arginine to maintain its nitrogen balance. These nutritional requirements place dogs halfway between carnivores and omnivores.
Range
As a domesticated or semi-domesticated animal, the dog is nearly universal among human societies. Notable exceptions once included:
* The Aboriginal Tasmanians, who were separated from Australia before the arrival of dingos on that continent
* The Andamanese peoples, who were isolated when Sea level rise, rising sea levels covered the land bridge to Myanmar
* The Fuegians, who instead domesticated the Fuegian dog, a different canid species
* Individual Pacific islands whose maritime settlers did not bring dogs, or where dogs died out after original settlement, notably the Mariana Islands, Palau and most of the Caroline Islands with exceptions such as Fais Island and Nukuoro, the Marshall Islands, the Gilbert Islands,[ New Caledonia,] Vanuatu, Tonga, Marquesas, Mangaia in the Cook Islands, Rapa Iti in French Polynesia, Easter Island, the Chatham Islands and Pitcairn Island (settled by the Mutiny on the Bounty, ''Bounty'' mutineers, who killed off their dogs to escape discovery by passing ships).
Dogs were introduced to Antarctica as sled dogs, but were later outlawed by international agreement due to the possible risk of spreading infections.
Roles with humans
Domestic dogs inherited complex behaviors, such as bite inhibition, from their wolf ancestors, which would have been pack hunters with a 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. These attributes have given dogs a relationship with humans that has enabled them to become one of the most successful animals today.
The 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
Hunting is the human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products ( fur/ hide, bone/tusks, horn/antler, ...
, herding
Herding is the act of bringing individual animals together into a group (herd), maintaining the group, and moving the group from place to place—or any combination of those. Herding can refer either to the process of animals forming herds in ...
, pulling loads, protection
Protection is any measure taken to guard a thing against damage caused by outside forces. Protection can be provided to physical objects, including organisms, to systems, and to intangible things like civil and political rights. Although th ...
, assisting police and the military
A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. It is typically authorized and maintained by a sovereign state, with its members identifiable by their distinct ...
, companionship
The concept of interpersonal relationship involves social associations, connections, or affiliations between two or more people. Interpersonal relationships vary in their degree of intimacy or self-disclosure, but also in their duration, in t ...
and Assistance dog, aiding disabled individuals. This influence on human society has given them the nickname "man's best friend
"Man's best friend" is a common phrase used to describe domestic dogs, referring to their millennia-long history of close relations, loyalty, friendship, and companionship with humans. The first recorded use of a related phrase is by Frederick ...
" in the Western world. In some cultures, however, dogs #As food, are also a source of meat.
Pets
It is estimated that three-quarters of the world's dog population lives in the developing world as feral, village, or community dogs, with pet dogs uncommon.
"The most widespread form of interspecies bonding occurs between humans and dogs" and the keeping of dogs as companions, particularly by elites, has a long history. Pet dog populations grew significantly after World War II as suburbanization increased. In the 1950s and 1960s, dogs were kept outside more often than they tend to be today (the expression "in the doghouse" - recorded since 1932 - to describe exclusion from the group implies a distance between the doghouse and the home) and were still primarily functional, acting as a guard, children's playmate, or walking companion. From the 1980s, there have been changes in the pet dog's role, such as the increased role of dogs in the emotional support of their human guardians. People and their dogs have become increasingly integrated and implicated in each other's lives to the point where pet dogs actively shape how a family and home are experienced.
There have been two significant trends occurring within the second half of the 20th century in pet dogs' changing status. The first has been Commodification of animals, "commodification", shaping it to conform to social expectations of personality and behavior. The second has been the broadening of the family's concept and the home to include dogs-as-dogs within everyday routines and practices.
A vast range of commodity forms aims to transform a pet dog into an ideal companion. The list of goods, services, and places available is enormous: from dog perfumes, couture, furniture and housing to dog groomers, therapists, trainers and caretakers, dog cafes, spas, parks and beaches and dog hotels, airlines and cemeteries. Dog training books, classes, and television programs proliferated as the process of commodifying the pet dog continued.
The majority of contemporary dog owners describe their pet as part of the family, although some ambivalence about the relationship is evident in the popular reconceptualization of the dog-human family as a pack. Some dog trainers, such as on the television program ''Dog Whisperer'', have promoted a Dominance (ethology), dominance model of dog-human relationships. However, it has been disputed that "trying to achieve status" is characteristic of dog-human interactions. The idea of the "Pack (canine)#Use in dog training, alpha dog" trying to be dominant is based on a disproved theory about wolf packs. Pet dogs play an active role in family life; for example, a study of conversations in dog-human families showed how family members use the dog as a resource, talking to the dog, or talking through the dog; to mediate their interactions with each other.
Increasingly, human family-members engage in activities centered on the dog's perceived needs and interests, or in which the dog is an integral partner, such as Musical canine freestyle, dog dancing and Doga (Dog Yoga), dog yoga.
According to statistics published by the American Pet Products Manufacturers Association in the National Pet Owner Survey in 2009–2010, an estimated 77.5 million people in the United States have pet dogs. The same source shows that nearly 40% of American households own at least one dog, of which 67% own just one dog, 25% two dogs and nearly 9% more than two dogs. There does not seem to be any Gender preference (disambiguation), gender preference among dogs as pets, as the statistical data reveal an equal number of male and female pet dogs. Although several programs promote pet adoption, less than one-fifth of the owned dogs come from Animal shelter, shelters.
A study using magnetic resonance imaging (MRI) to compare humans and dogs showed that dogs have the same response to voices and use the same parts of the brain as humans do. This gives dogs the ability to recognize human emotional sounds, making them friendly social pets to humans.[
]
Workers
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),[Dewey, T. and S. Bhagat. 2002.]
''Canis lupus familiaris''
Animal Diversity Web. hunting (hounds, pointers) and rodent control (terriers). Other types of working dogs include search and rescue dogs, detection dogs trained to detect Illegal drug trade, illicit drugs or chemical weapons; guard dogs; dogs who assist fishermen with the use of nets; and dogs that pull loads. In 1957, the dog Laika became the first animal to be launched into Earth orbit, aboard the Soviet space program, Soviets' ''Sputnik 2''; she died during the flight.
Various kinds of service dogs and assistance dogs, including guide dogs, hearing dogs, mobility assistance dogs and psychiatric service dogs, assist individuals with disabilities. Some dogs owned by people with epilepsy have been shown to alert their handler when the handler shows signs of an impending seizure, sometimes well in advance of onset, allowing the guardian to seek safety, medication, or medical care.
Athletes and models
People often enter their dogs in competitions, such as breed-conformation shows or List of dog sports, sports, including racing, sledding and agility competitions. In conformation shows, also referred to as breed shows, a judge familiar with the specific dog breed evaluates individual purebred dogs for conformity with their established breed type as described in the breed standard. As the breed standard only deals with the dog's externally observable qualities (such as appearance, movement and temperament), separately tested qualities (such as ability or health) are not part of the judging in conformation shows.
Food
Dog meat is consumed in some East Asian countries, including Korea, China, Vietnam and the Philippines, which dates back to antiquity. Based on limited data, it is estimated that 13–16 million dogs are killed and consumed in Asia every year. In China, debates have ensued over banning the consumption of dog meat. Following the Sui and Tang dynasties of the first millennium, however, people living on northern China's plains began to eschew eating dogs, which is likely due to Buddhism and Islam's spread, two religions that forbade the consumption of certain animals, including the dog. As members of the upper classes shunned dog meat, it gradually became a social taboo to eat it, even though the general population continued to consume it for centuries afterward. Dog meat is also consumed in some parts of Switzerland. Other cultures, such as Polynesia and pre-Columbian Mexico, also consumed dog meat in their history. Dog fat is also reportedly believed to be beneficial for the lungs in some parts of Poland and Central Asia. Proponents of eating dog meat have argued that placing a distinction between livestock and dogs is Western hypocrisy and that there is no difference in eating different animals' meat.
In Korea, the primary dog breed raised for meat, the ''Nureongi'', differs from those breeds raised for pets that Koreans may keep in their homes.[Pettid, Michael J., ''Korean Cuisine: An Illustrated History'', London: Reaktion Books Ltd., 2008, 25. ]
The most popular Korean dog dish is 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 Qi, ''gi'', or the body's vital energy. A 19th-century version of bosintang 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 prevalent in Korea with a segment of the population, dog is not as widely consumed as beef, pork and chicken.
Health risks
In 2018, the WHO reported that 59,000 people died globally from rabies, with 59.6% in Asia and 36.4% in Africa. Rabies is a disease for which dogs are the most important vector. Significant dog bites affect tens of millions of people globally each year. Children in mid-to-late childhood are the largest percentage bitten by dogs, with a greater risk of injury to the head and neck. They are more likely to need medical treatment and have the highest death rate. Sharp claws with powerful muscles behind them can lacerate flesh in a scratch that can lead to serious infections.
In the Dogs in the United States, U.S., cats and dogs are a factor in more than 86,000 falls each year. It has been estimated that around 2% of dog-related injuries treated in U.K. hospitals are domestic accidents. The same study found that while dog involvement in road traffic accidents was difficult to quantify, dog-associated road accidents involving injury more commonly involved two-wheeled vehicles.
''Toxocara canis'' (dog roundworm
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a bro ...
) 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. Untreated toxocariasis can cause retinal damage and decreased vision. Dog feces can also contain hookworms that cause cutaneous larva migrans in humans.
Health benefits
Dogs suffer from the same common disorders as humans; these include cancer, diabetes, heart disease and neurologic disorders. Their pathology is similar to humans, as is their response to treatment and their outcomes. Researchers are identifying the genes associated with dog diseases similar to human disorders, but lack mouse models to find cures for both dogs and humans. The genes involved in canine obsessive-compulsive disorders led to the detection of four genes in humans' related pathways.[
The scientific evidence is mixed as to whether a dog's companionship can enhance human physical health and psychological well-being.] Studies suggesting that there are benefits to physical health and psychological well-being have been criticized for being poorly controlled. It found that "the health of elderly people is related to their health habits and social supports but not to their ownership of, or attachment to, a companion animal." Earlier studies have shown that people who keep pet dogs or cats exhibit better mental and physical health than those who do not, making fewer visits to the doctor and being less likely to be on medication than non-guardians.
A 2005 paper states "recent research has failed to support earlier findings that pet ownership is associated with a reduced risk of cardiovascular disease, a reduced use of general practitioner services, or any psychological or physical benefits on health for community dwelling older people. Research has, however, pointed to significantly less absenteeism from school through sickness among children who live with pets." In one study, new guardians reported a highly significant reduction in minor health problems during the first month following pet acquisition. This effect was sustained in those with dogs through to the end of the study.
People with pet dogs took considerably more physical exercise than those with cats and those without pets. The results provide evidence that keeping pets may have positive effects on human health and behavior and that for guardians of dogs, these effects are relatively long-term. Pet guardianship has also been associated with increased coronary artery disease survival. Human guardians are significantly less likely to die within one year of an acute myocardial infarction than those who did not own dogs. The association between dog ownership and adult physical activity levels has been reviewed by several authors.
The health benefits of dogs can result from contact with dogs in general, not solely from having dogs as pets. For example, when in a pet dog's presence, people show reductions in cardiovascular, behavioral and psychological indicators of anxiety. Other health benefits are gained from exposure to immune-stimulating microorganisms, which can protect against allergies and autoimmune diseases according to the hygiene hypothesis. The benefits of contact with a dog also include social support, as dogs cannot only provide companionship and social support themselves but also act as facilitators of social interactions between humans. One study indicated that wheelchair users experience more positive social interactions with strangers when accompanied by a dog than when they are not. In 2015, a study found that pet owners were significantly more likely to get to know people in their neighborhood than non-pet owners.
Using dogs and other animals as a part of therapy dates back to the late 18th century, when animals were introduced into mental institutions to help socialize patients with mental disorders. Animal-assisted intervention research has shown that animal-assisted therapy with a dog can increase social behaviors, such as smiling and laughing, among people with Alzheimer's disease. One study demonstrated that children with ADHD and conduct disorders who participated in an education program with dogs and other animals showed increased attendance, increased knowledge and skill objectives and decreased antisocial and violent behavior compared with those not in an animal-assisted program.
Cultural importance
Dogs were depicted to symbolize Guide, guidance, protection, loyalty, fidelity, faithfulness, alertness, and love. In ancient Mesopotamia, from the Babylonia, Old Babylonian period until the Neo-Babylonian Empire, Neo-Babylonian, dogs were the symbol of Ninisina, the goddess of healing and medicine, and her worshippers frequently dedicated small models of seated dogs to her. In the Neo-Assyrian Empire, Neo-Assyrian and Neo-Babylonian periods, dogs were used as emblems of magical protection. In China, Korea and Japan, dogs are viewed as kind protectors.
In mythology, dogs often serve as pets or as watchdogs. Stories of dogs guarding the gates of the underworld recur throughout Indo-European mythologies and may originate from Proto-Indo-European religion. In Greek mythology, Cerberus is a three-headed, dragon-tailed watchdog who guards the gates of Hades. Dogs are also associated with the Greek goddess Hecate. In Norse mythology, a bloody, four-eyed dog called Garmr guards Helheim. In Persian mythology, two four-eyed dogs guard the Chinvat Bridge. In Welsh mythology, Annwn is guarded by Cŵn Annwn. In Hindu mythology, Yama, the god of death, owns two watchdogs who have four eyes. They are said to watch over the gates of Naraka. A black dog is also considered to be the ''vahana'' (vehicle) of Bhairava (an incarnation of Shiva).
In Christianity, dogs represent faithfulness. Within the Roman Catholic denomination specifically, the iconography of Saint Dominic includes a dog, after the saint's mother dreamt of a dog springing from her womb and becoming pregnant shortly after that. As such, the Dominican Order (Ecclesiastical Latin: ''Domini canis'') means "dog of the Lord" or "hound of the Lord" (Ecclesiastical Latin: ''Domini canis''). In Christian folklore, a church grim often takes the form of a black dog to guard Christian churches and their churchyards from sacrilege. Jewish law does not prohibit keeping dogs and other pets. Jewish law requires Jews to feed dogs (and other animals that they own) before themselves and make arrangements for feeding them before obtaining them. The view on dogs in Islam is mixed, with some schools of thought viewing it as unclean, although Khaled Abou El Fadl states that this view is based on "pre-Islamic Arab mythology" and "a tradition to be falsely attributed to the Prophet." Therefore, Sunni Malaki and Hanafi jurists permit the trade of and keeping of dogs as pets.
Terminology
* ''Dog'' – the species (or subspecies) as a whole, also any male member of the same.
* ''Bitch'' – any female member of the species (or subspecies).
* ''Puppy'' or ''pup'' – a young member of the species (or subspecies) under 12 months old.
* ''Sire'' – the male parent of a litter.
* ''Dam'' – the female parent of a litter.
* ''Litter (animal), Litter'' – all of the puppies resulting from a single whelping.
* ''Whelping'' – the act of a bitch giving birth.
* ''Whelps'' – puppies still dependent upon their dam.
See also
* Cat–dog relationship
* Cynanthropy
* Dognapping
* Domesticated silver fox
* Lists of dogs
*List of individual dogs
* Portal:Dogs, Dogs portal
* Portal:Mammals, Mammals portal
References
Bibliography
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External links
Biodiversity Heritage Library bibliography
for ''Canis lupus familiaris''
Fédération Cynologique Internationale (FCI) – World Canine Organisation
Dogs in the Ancient World
an article on the history of dogs
* View th
dog genome
on Ensembl
Genome of ''Canis lupus familiaris'' (version UU_Cfam_GSD_1.0/canFam4)
via UCSC Genome Browser
Data of the genome of ''Canis lupus familiaris''
via NCBI
Data of the genome assembly of ''Canis lupus familiaris'' (version UU_Cfam_GSD_1.0/canFam4)
via NCBI
{{Authority control
Dogs,
Wolves
Scavengers
Cosmopolitan mammals
Animal models
Extant Late Pleistocene first appearances
Mammals described in 1758
Taxa named by Carl Linnaeus