All About Dogs

 The dog (Canis lupus familiaris) is a domestic mammal belonging to the Canidae family (order Carnivora). It is a gray wolf subspecies (Canis lupus) that is linked to foxes and jackals. The dog is one of the world's two most prevalent and popular domestic animals (the cat is the other). It has coexisted with humans for almost 12,000 years as a hunting companion, guardian, object of disdain or affection, and friend.

From the gray wolf, the dog evolved into more than 400 unique breeds. Human humans have been instrumental in developing canines that meet a variety of societal demands. Dogs were created using the most primitive kind of genetic engineering to amplify instincts that were evident from their early encounters with humans. Although the exact specifics of dog evolution are unknown, the earliest dogs were hunters with acute senses of sight and scent. Humans evolved these tendencies and formed new breeds in response to need or want.

Dogs are viewed differently throughout the world. Dogs' characteristics of loyalty, friendliness, protectiveness, and devotion have won them a prominent position in Western society, and dog care and feeding has grown to be a multibillion-dollar industry in the United States and Europe. While Western society has placed a premium on the human-dog relationship, dogs are not viewed in the same regard in many developing nations and parts of Asia. Dogs are used as guards, beasts of burden, and even food in some parts of the world, but they are protected and cherished in the United States and Europe. Dogs were regarded sacred in ancient Egypt under the reign of the pharaohs.

Canine ancestors and history

Ancestry

Paleontologists and archaeologists have concluded that a small mammal like a weasel lived in the environs of what are now regions of Asia some 60 million years ago. Miacis is the genus that gave rise to the modern canids: dogs, jackals, wolves, and foxes. Although Miacis left no direct offspring, doglike canids evolved from it. Miacis evolved into the first genuine dog, Cynodictis, between 30 and 40 million years ago. This was a medium-sized animal, longer in stature than in height, with a long tail and a moderately brushy coat. Cynodictis developed two branches over the millennia, one in Africa and one in Eurasia. Tomarctus was the name given to the Eurasian branch, which is the ancestor of wolves, dogs, and foxes.

Dogs descended directly from wolves (Canis), and the now-extinct wolf lineages that generated dogs split off from the one that produced present live wolves between 27,000 and 40,000 years ago. The exact date and location of dog domestication are debatable. However, there is compelling genetic evidence suggesting the initial domestication events happened between 14,000 and 29,000 years ago in northern Eurasia. Wolves presumably assisted in their domestication in this region by following nomadic peoples in northern Eurasia and devouring the carcasses of game animals left behind by hunters.

The majority of research concur that domestication did not occur in a single discrete event. It was a process that occurred over thousands of years—likely involving dog populations that arose in different parts of Eurasia at different periods, with dogs and wild wolves continuing to interbreed and early dog populations being supplanted by later dog populations. Certain genetic investigations have established evidence of early domestication in specific places. According to one study, wolves were domesticated 16,300 years ago in China to use as cattle, while another claims that early canines originated from a small breed of gray wolf that lived in India. Additionally, genetic evidence indicates that dogs did not accompany the first humans to the New World over 15,000 years ago, but rather arrived in the Americas around 10,000 years ago. According to one study, certain dogs may have descended from the jackal rather than the wolf. These dogs, discovered in Africa, may have spawned several of today's indigenous African breeds.

Regardless of their origins, canids have some traits. They are mammals capable of producing live young. Females possess mammary glands and breastfeed their young. The early breeds possessed upright ears and pointed or wedge-shaped muzzles, resembling the modern northern breeds. The majority of carnivores have comparable dental features, which helps paleontologists identify them. They acquire two distinct sets of teeth: deciduous ("baby") teeth and permanent ("adult") teeth.

Canids walk on their toes, in contrast to a flat-footed animal such as the bear, which walks on its heels. As with the majority of animals, dogs have body hair and are homeothermic—that is, they have an internal thermostat that allows them to maintain a steady body temperature regardless of the outside temperature.

By the beginning of the Bronze Age, fossil evidence indicates that five unique breeds of dogs existed (about 4500 BCE). Mastiffs, wolf-type dogs, sight hounds (such as the Saluki or greyhound), pointing dogs, and herding dogs were some of them.

Contribution to human societies

Dogs were among the first domesticated animals and played a significant role in the history of human civilisation. They acted as hunting allies and protectors against predators in hunter-gatherer societies. When livestock was domesticated approximately 7,000–9,000 years ago, dogs were used as herders and protectors of sheep, goats, and cattle. Although many continue to function in these capacities, dogs are mostly used for companionship and social purposes. Today, dogs are used as guides for the blind and disabled, as well as for law enforcement operations. Dogs are even utilized in nursing homes and hospitals as a form of therapy to assist patients in their rehabilitation. Humans have created a diverse range of canines that have been modified to perform a number of tasks. This has been facilitated by advances in veterinary medicine and animal husbandry.

Dogs were believed to have god-like characteristics in ancient Egypt. They were pampered by their own attendants, wore jeweled collars, and ate only the finest foods. Only royalty were authorized to possess purebred dogs, and when a ruler died, his favorite dog was frequently interred with him to protect him in the afterlife.

Dogs have been depicted on walls, tombs, and scrolls throughout Europe, the Middle East, and North America dating all the way back to the Bronze Age. Frequently, dogs are portrayed hunting with their human counterparts. Dog statues guard the entrances to the burial crypts. In several instances, these dogs bear a striking resemblance to current canines. These treasures bear indelible witness to the importance humans have accorded the dog throughout history.

Breeds originated

Once it was established that dogs were faster, stronger, and had superior vision and hearing to humans, those specimens exhibiting these characteristics were interbred to enhance these characteristics. In the Middle East, noblemen venerated swift-footed sight hounds, whereas in Europe, muscular dogs such as the mastiff were created to protect home and traveler from harm.

Other varieties of dogs evolved as civilization changed and agriculture—in addition to hunting—became a method of subsistence. Farmers relied on herding and guarding dogs to protect their herds. Simultaneously, little breeds gained popularity as toys and companions for noble families. In China, the Pekingese and other small breeds such as the Chihuahua were bred as lapdogs. The terrier breeds were developed primarily in England to eradicate rats from granaries and barns. Breeds of pointing and retrieving dogs were chosen for specific responsibilities associated to assisting the hunter in locating and capturing game. Numerous breeds are extremely ancient, while others were produced as recently as the nineteenth century.

Characteristics and functions

Characteristics générale

Dogs come in an array of colors, shapes, and sizes. While it may be difficult to believe that a massive Great Dane and a small poodle are members of the same species, they are genetically identical and have similar anatomical traits. All dogs have 78 chromosomes, or 39 pairs (humans have 23 pairs), and each pair has one chromosome from each parent. An adult dog's normal temperature (rectal) ranges between 100 and 102.5 °F.