The Domestic Dog

What do we know about dogs???

Domestic dog

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Wolves were no doubt familiar to the early peoples of Eurasia, where the two species ranged over the same territory, hunted many of the same animals and even scavenged at each other’s kills. Both were intelligent and resourceful, and both lived in tightly structured bands. In time these similarities permitted outright competition to develop into a sort of cooperation:

People likely took advantage of the skill of the wolves in locating and driving prey, and wolves certainly learned that people’s camps yielded a dependable supply of bones, scraps, and other edible refuse. From among these camp hangers-on, people adopted orphaned or captured cubs, tamed them, bred them and by about 12,000 years ago produced a line of companionable animals quite at home in human society—dogs.

1. Origin of word

Back in the 14th Century in England, the word “hound” was used for all domestic canines, and “dog” referred to a subtype of hound. Many years later i.e. by the 16th century, dog had become the general word, and hound had begun to refer only to types used for hunting.

The domestic dog (Canis familiaris) is a carnivore, from the family Canidae; jackal and fox also belong to this family. In fact, the domestic dog is the most widely abundant carnivore.

Two characteristics distinguish the dog from other canids and from other animal species: The first is its worldwide distribution in close association with humans and the second is the enormous amount of variability found within the subspecies.

2. Terminology

Anadult male is dog and an adultfemale is bitch (In some countries, especially in North America, dog is used instead due to the vulgar connotation of bitch) and a young dog i.e. immature male or female, is called puppy.

Did you know that "whelp" is an alternate term for puppy?

More terms

• A group of puppies from the same gestation period is a litter.

• The father of a litter is a sire.

• The mother of a litter is a dam.

• A group of any three or more adults is a pack.

Physical Characteristics

Domestic dogs vary widely in size. The Shih Tzu, for example, is 20 to 28 cm (8 to 11 in) in length and weighs 4 to 7 kg (9 to 15 lb). The Irish wolfhound is at the other end of the scale, measuring about 71 to 94 cm (about 28 to 37 in) at the shoulder and weighing up to about 61 kg (about 135 lb)

Coat color, length, texture, and pattern also vary greatly. The muzzle may appear shortened, as in the Pekingese, or elongated, as in the Doberman pinscher.

domestic dog

Limbs are relatively short in the basset hound and dachshund, but long in the greyhound. Ear shape and carriage also vary, but these characteristics may be influenced by a dog owner’s decision to crop, or cut, the ears to make them stand up. Some dogs, notably the chow chow, even have a naturally blue-black tongue.

Despite these differences, all breeds of the domestic dog are essentially identical in anatomy. The skeleton of the domestic dog has an average of 321 bones. Variation reflecting differences in the number of bones in the tail and the presence of a dewclaw, an extra digit on the paw that not all breeds have.

The rib cage consists of 13 pairs of ribs; the spine has 7 cervical vertebrae, 13 thoracic vertebrae, 7 lumbar vertebrae, and 3 sacral vertebrae. Rear paws have four complete digits and front paws have four or five digits. Most puppies have 28 temporary teeth, which are replaced with 42 permanent teeth at about six months of age.

domestic dog

Some breed differences evolved to help dogs survive in their native environment or occupation. For example, dogs that lived and worked outdoors, such as the Komondor of Hungary, needed a thick, weather-resistant coat to protect them from the elements and, perhaps, the biting teeth of predatory animals.

Just as distinct physical characteristics became trademarks in some breeds, unusual sensory abilities characterize others. Most dogs are able to detect scents and hear high-pitched sounds that are beyond human perception, but some breeds have especially acute sensory skills. The bloodhound, for instance, can follow a four-day-old track using its highly developed sense of smell.

Other breeds with a keen sense of smell include the German shepherd, golden retriever, beagle, and Newfoundland. These dogs have been trained for varied duties as detecting hidden drugs, explosives, termites, and even a decomposing body immersed in deep water. We also have good companion dogs such as English bulldog and french bulldog.

3. Breeds

Initially people began to develop distinct types of dog for particular jobs - hounds to hunt game, mastiffs to guard property, and shepherd dogs to herd livestock. They selectively bred these dogs to be physically and temperamentally suited for their role— keen noses for hunting, long legs for racing, strength and stamina for hard outdoor work, and a strong protective instinct in dogs needed for guard duties.

Later, when humans better understood and were able to manipulate the laws of inheritance, came the terriers and companion dogs. Once dogs started to be kept more for companionship and as pets than for practical purposes, their appearance began to take precedence over function. Popular Dog breeds include:Labrador Retriever, Bulldog, German Shepherd, Bull Terrier, Beagle and many others

A breed of dog is produced by selecting and mating dogs with certain desired characteristics. The offspring of such mating are then inbred, i.e. mated with litter mates or close relatives. After about eight generations, the line usually breeds true i.e. most offspring resemble each other. Then standard traits can be established for the new breed.
A purebred dog is one that conforms to the standards of a certain breed and whose lineage or pedigree has been recorded for a certain period of time.One of the principal functions of a kennel club is to maintain the records of lineage of individual purebred dogs in order to preserve breed standards.
Of the more than 300 breeds of dogs that exist worldwide, 150 are recognized by the American Kennel Club (AKC), the primary kennel club in the United States.
The AKC organizes the 150 breeds it recognizes into seven groups (plus a miscellaneous category), based on physical and temperamental characteristics and the purpose for which the breed was originally developed. The club classifies breeds as terrier, working, sporting, hound, herding, toy, and nonsporting.
For more information visit this post about dog breeds. 

English Bulldog information

4. Lifespan

Mixed-breed dogs have been found to run faster and live longer than their pure-bred parents

A study in 2013, found that mixed breeds live on average, 1.2 years longer than pure breeds, and that the heavier the dog the shorter its lifespan.

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. Individual dogs may live well beyond the median of their breed.

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.Several breeds though, including Miniature Bull Terriers, Bloodhounds and Irish Wolfhounds are nearly as short-lived, with median longevities of 6 to 7 years.

The longest-lived breeds -Toy Poodles, Japanese Spitz, Border Terriers, and Tibetan Spaniels, have median longevities of 14 to 15 years.

The dog widely reported to be the longest-lived is "Bluey", who died in 1939 and was claimed to be 29.5 years old at the time of his death. On December 5th2011, Pusuke, the world's oldest living dog recognized by Guinness Book of World Records, died aged 26 years and 9 months.

5. Reproduction

Dogs generally reach sexual maturity at about six months of age, with small breeds often maturing earlier than large breeds. Female dogs, or bitches, become sexually receptive to mating during a period called estrus (also called season or heat), which occurs about twice a year for 6 to 12 days. After a gestation period of about 63 days, an average litter of three to six (3-6) puppies is born.

Blind and unable to stand, new born puppies are helpless and spend 90 percent of their time sleeping and 10 percent nursing. Becoming chilled is the greatest danger facing a healthy new born puppy because its immature circulatory system cannot sustain an adequate body temperature. For this reason, new born puppies tend to stay close to their mother or cuddle together for warmth. Mothers clean, nurse, and defend their pups until they can live on their own, but fathers do not involve themselves in the care of the young. 

domestic dog

Neutering refers to the sterilization of animals, usually by removal of the male's testicles or the female's ovaries and uterus, in order to eliminate the ability to procreate and reduce sex drive. Because of the overpopulation of dogs in some countries, many animal control agencies, such as the American Society for the Prevention of Cruelty to Animals (ASPCA), advise that dogs not intended for further breeding should be neutered, so that they do not have undesired puppies that may have to later be euthanized.

6. Intelligence, behaviour and communication

• Intelligence

Dog intelligence is the ability of a dog to perceive information and retain it as knowledge for applying to solve problems.


  Dogs have been shown to learn by inference. Dogs have advanced memory skills. A study documented the learning and memory capabilities of a border collie, "Chaser", who had learned the names and could associate by verbal command over 1,000 words. Dogs are able to read and react appropriately to human body language such as gesturing and pointing and to understand human voice commands.  

Another study indicated that after undergoing training to solve a simple manipulation task, dogs that are faced with an insoluble version of the same problem look at the human. Modern domestic dogs use humans to solve their problems for them.

• Behavior

Dog behavior is the internally coordinated responses (actions or inactions) of the domestic dog (individuals or groups) to internal and/or external stimuli.

As the oldest domesticated species, 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 our behaviors.

Behavioral scientists have uncovered a surprising set of social-cognitive abilities in the otherwise humble domestic dog. These abilities are not possessed by the dog's closest canine relatives nor by other highly intelligent mammals such as great apes. Rather, these skills parallel some of the social-cognitive skills of human children.

Communication (How do dogs speak to each other?)

These communication behaviors include eye gaze, facial expression, vocalization, body posture (including movements of bodies and limbs) and gustatory communication (scents, pheromones and taste).

Humans communicate with dogs by using vocalization, hand signals and body posture.

7. Diet

Dogs are variously described in scholarly and other writings as carnivores or omnivores. Dogs can adapt to a wide-ranging diet, unlike obligate carnivores and are not dependent on meat-specific protein nor a very high level of protein in order to fulfil their basic dietary requirements.

Dogs will healthily digest a variety of foods, including vegetables and grains, and can consume a large proportion of these in their diet.All-meat diets are not recommended for dogs though, due to their lack of calcium and iron.

8. Roles with humans

Domestic dogs inherited some sophisticated forms of social cognition and communication from wolves, which 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 species on the planet today.

The dog's value to early human hunter-gatherers led to them quickly becoming ubiquitous across world cultures. Dogs perform many roles for people like hunting, herding, pulling loads, protection, assisting police and military, companionship and more recently, aiding handicapped individuals.

This influence on human society has given them the nickname "man's best friend" in the Western world. In some cultures, however, dogs are also a source of meat.

(a) As pets (man’s best friend)

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 and were still primarily functional, acting as a guard, children's playmate, or walking companion.

From the 1980s, there have been changes in the role of the pet dogto the point where pet dogs actively shape the way a family and home are experienced.

There have been two major trends in the changing status of pet dogs. The first has been the 'commodification' of the dog - shaping it to conform to human expectations of personality and behaviour, and the broadening of the concept of the family and the home to include dogs-as-dogs within everyday routines and practices.

There are a vast range of commodity forms available 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.

The latest study using magnetic resonance imaging (MRI) comparing humans and dogs showed that dogs have same response to voices and use the same parts of the brain as humans do. This gives dogs the ability to recognize emotional human sounds, making them friendly social pets to humans.

(b) Sports and shows

People often enter their dogs in competitionssuch as breed-conformation shows or 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 externally observable qualities of the dog (such as appearance, movement, and temperament).

(c) Health risks to humans

The WHO reported in 2005that 55,000 people died in Asia and Africa from rabies, a disease for which dogs are the most important vector.

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.

A Colorado study found that bites in children were less severe than bites in adults.The incidence of dog bites in the US is 12.9 per 10,000 inhabitants, but for boys aged 5 to 9, the incidence rate is 60.7 per 10,000. Sharp claws with powerful muscles behind them can lacerate flesh in a scratch that can lead to serious infections.

In the UK between 2003 and 2004, there were 5,868 dog attacks on humans, resulting in 5,770 working days lost in sick leave.

(d) Health benefits for humans

The scientific evidence is mixed as to whether companionship of a dog can enhance human physical health and psychological wellbeing.

Studies suggesting that there are benefits to physical health and psychological wellbeing have been criticised for being poorly controlled and finding 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 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.

In one study, new guardians reported a highly significant reduction in minor health problems during the first month following pet acquisition, and this effect was sustained in those with dogs through to the end of the study.

The results provide evidence that keeping pets may have positive effects on human health and behaviour, and that for guardians of dogs these effects are relatively long-term. Pet guardianship has also been associated with increased coronary artery disease survival, with human guardians being significantly less likely to die within one year of an acute myocardial infarction than those who did not own dogs.

(e) Medical detection dogs

Medical detection dogs are capable of detecting diseases by sniffing a person directly or samples of urine or other specimens. Dogs can detect odour in one part per trillion, as their brain's olfactory cortex is (relative to total brain size) 40 times larger than humans.

Each dog is trained specifically for the detection of single disease from the blood glucose level indicative to diabetes to cancer. To train a cancer dog requires 6 months. A Labrador Retriever called Daisy has detected 551 cancer patients with an accuracy of 93 percent and received the Blue Cross (for pets) Medal for her life-saving skills.