Canine Behavior

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The modern domestic dog, Canis lupus familiaris, was created, naturally selected, and eventually artificially selected into the genetic diversity we see today, all to aid in the survival and efficiency of human civilization. The domestic dog was selected for by both canine and human behavior, has contributed to the survival and increased efficiency of human populations, and continues to exist in order to serve humans. Some argue that Canis lupus familiaris no longer contributes to our fitness as a species, and that we should no longer keep them as pets in consideration of their well-being, but others assert that we still need them and are capable of keeping them content.

History

Wolves were domesticated between 30,000 and 15,000 years ago in East Asia, Western Europe, or both. The Canis genus diverged from foxes and the Homo genus diverged from the other Great Apes around 6 million years ago, as adaptations to the most recent Ice Age. Within the last 100,000 years, a species of wolf from the Late Pleistocene diverged into the modern wolf and the modern domestic dog. The process of domestication still is not fully agreed upon, but biologists typically believe in a kind of socialization hypothesis—there existed genetic variation in the sociability of wolves that contributed to their tolerance of humans. Wolves are believed to have evolved a commensal relationship with humans—wolves approached human campfires, attracted to the smell of cooking meat, and eventually chose their territories surrounding humans and alerted them when predators approached. The relationship between wolves and humans later developed into hunting companionship and more comfortability and trust between the two species. Eventually this led to the speciation and total domestication of dogs throughout most of Asia and Europe, eventually resulting in the hundreds of standardized dog breeds we have today. There is some debate whether this domestication/speciation event happened exactly once, or if it happened in multiple regions around the same time; many epigenetic studies have claimed evidence of the latter, but these studies tend not to acknowledge the admixture of wolves and domesticated dogs for several generations after the initial speciation event(s). A 2015 study that did account for the early interbreeding of wolves and domestic dogs indicates that only one domestication event was necessary to explain the wide variety of breeds that have been developed over the past 15,000 years.

The initial coevolution of humans and wolves that resulted in the domesticated dog was driven by mutual benefit—living together and cooperating would have offered food and protection for the wolves, increased detection of enemies for the humans, and improved hunting success for both. Whichever genes selected for this mutualistic relationship in both species increased their own chances of propagation by increasing the survival and efficiency of both populations. Even with weak selection pressures, which were likely the case based on how long it took for the domestication process to happen, the humans and wolves involved could acquire food and fend off enemies more easily, allowing them more time and energy to focus on reproduction, shelter, and social development. Although no researchers have identified specific genes that may have led to humans’ ability to domesticate wolves or wolves’ ability to be domesticated, these abilities existed somewhere within their genetic repertoires and ultimately led to the differential survival of cohabiting humans and wolves over their less social counterparts. Over thousands of years thereafter, humans have bred these domestic dogs for the traits that best suit humans’ needs. This has been done through artificial selection—the manipulated mating of the two available dogs that most closely fit the demands of the intended job.

Artificial Selection

Within the subspecies of domestic dog, there are now myriad races, or breeds, that have been artificially selected for over the years to perform specific jobs for humans. We have dogs to work on farms, pulling carts and herding livestock; we have dogs that are specialized to watch and guard our homes and estates; and we have dogs to aid in hunting. Many of these breeds are no longer necessary, and have been replaced by machines and automation, but they originated from their potential to aid in our survival. Although the domestic dog likely came from one instance of domestication, artificial selection has resulted in many analogous dog breeds in different regions that are genetically distinct. In most areas, the domestic dog can have a wide variety of shapes and sizes. Asian breeds include the Shiba, Akita, Tosa, Shih Tzu, and Shar Pei; African breeds include the Basenji and Boerboel; American breeds range from the Xolo to the Malamute; and European breeds vary in size and shape from the Fox Terrier to the English Mastiff. The Malamute and Samoyed are sled dogs from opposite sides of the Northern hemisphere, and various nations have developed their own Molosser (mastiff-like) breed over the centuries to guard estates from intruders. These breeds come in sizes ranging from the 4-lb chihuahua to the 280-lb English Mastiff), and coat patterns on multiple genotypic loci ranging from white with black spots (Dalmatian, Dogo Argentino, German Shorthair Pointer) to brindle (many Pit Bulls and Mastiffs), Merle (Cardigan Welsh Corgi, Australian Shepherd), and tricolor (Beagle, Jack Russell Terrier, Pembroke Welsh Corgi). With all the genetic variation between different breeds of domestic dog, it is interesting that such convergent selection has occurred; this has happened because humans have guided these dog breeds to serve specific purposes in order to help us survive more efficiently.

The oldest use for which the domestic dog was developed is probably hunting. Some breeds, like the Norwegian Elkhound, Caucasian Ovcharka, and Dachshund were created to flush out and chase prey, actively participating in the killing of animals. The Ovcharka was bred to be very large—sometimes over 200 lbs—in order to be physically capable of pursuing bears with minimal risk of injury. Norwegian elkhounds somewhat resemble sled dogs or wolves, and they were bred for speed and endurance in order to chase elk and reindeer over long distances. Dachshunds were bred to have long muscular bodies and short legs in order to flush foxes and badgers from their burrows and chase them. Other breeds were created to scare birds into flight and retrieve them after they have been killed or wounded—examples include pointers, retrievers, setters, water dogs, and spaniels. Terriers were bred to chase and kill rodents and other small animals. Two other major groups of hunting dogs include sighthounds and scenthounds. Many scenthounds, such as the Bloodhound, coonhounds, and Basset Hound, have developed long droopy ears to kick up dust and folds of loose skin to accumulate scent particles so the dogs can find their targets. Other scenthounds include the Catahoula Leopard Dog and Rhodesian Ridgeback. Sighthounds have been independently developed all over the world to locate and chase down prey. They have dolichocephalic (elongated) faces to improve their vision and long slender bodies that enable them to achieve high speeds to chase rabbits and other small, fast animals. The most well-known sighthound is the greyhound from England, but other sighthounds include the Russian Borzoi, the Afghan Hound, the Persian Saluki, the Egyptian Pharaoh Hound, the Spanish Galgo, and the Azawakh from West Africa. The vast genetic variability in hunting dogs illustrates how significant the domestic dog has been in helping humans acquire food.

In addition to their usefulness in hunting for food, dogs have been used for farming since the domestication of ungulates and other non-canid animals. Farm jobs for dogs include plowing, herding, killing pests, and livestock protection. Boerboels, Greater Swiss Mountain Dogs, and Rottweilers were bred to be big and strong so they can pull carts on farms. Many dog breeds on every continent have been created for the purpose of herding stubborn ungulates such as sheep, cattle, and goats. The Australian Cattle Dog and the two convergent breeds of Welsh Corgi (Pembroke and Cardigan) were designed to have a form of dwarfism so that their legs are short enough to run underneath sheep and cattle to get on either side of them, and they were bred to bark and bite at the stubborn animals’ heels to convince them to go where they’re told. The Old English Sheepdog, Rough Collie, Border Collie, Bearded Collie, and Shetland Sheepdog all originated in the United Kingdom to herd sheep as well. The Beauceron and Briard are from France, the Australian Kelpie is from Australia, and the Australian Shepherd is from the United States. The Bernese Mountain Dog in Switzerland, the Beauceron in France, and the Belgian Malinois were bred to herd larger livestock, specifically cattle. 

While steering sheep and cattle toward food and shelter are important to keep them healthy, keeping them safe is also essential to farming livestock, and there are several other dog breeds designed to be livestock guardians. These include the Hungarian Kuvasz and Komondor, the Great Pyrenees, the Anatolian Shepherd from Turkey, the Central Asian Shepherd, and the Tibetan Mastiff. The Komondor was bred to look somewhat like the sheep it protects, but most of the other livestock guardian breeds were designed to be large and intimidating in order to discourage predators from attacking livestock. All of these drastically different breeds show that farm dogs’ genetic variability rivals that of the domestic dogs that were bred to aid in hunting.

Another way dogs have aided in human survival, originating around the same time as farming, is the use of dogs for transportation. Some sled dogs were originally bred to be big and strong, like the Alaskan Malamute, Akita, and Chinook, in order to have enough power to get a heavy sled moving. Other sled dogs were bred for endurance, like the Siberian Husky, Samoyed, and Greenland Dog, in order to keep the sled going until it reaches its destination. Other sled dogs include the Norwegian Elkhound, American Eskimo Dog, and Finnish Spitz. Dog sleds are now used for sport more often than transportation, but many Northern peoples may not be around today if they hadn’t been able to use these dogs for transportation and hunting. One of the most popular sled dogs around today is the Alaskan Husky, which is a mixed breed with most of its heritage from the Alaskan Malamute and Siberian Husky but with other progenitors from breeds such as the Border Collie and Anatolian Shepherd. The transition to using dog sleds for sport rather than transportation, combined with the relatively new access to other breeds of dogs, has led to the development of these new sled dogs. This group of domestic dogs was bred in various regions for stamina and intelligence, and they have been known to rescue people from ice-related predicaments in the Northern regions where they originated.

Some dog breeds were initially created with the purpose of rescuing people from snow, ice, and/or water. The Saint Bernard was developed in the Swiss Alps (independently from the Bernese and Greater Swiss Mountain Dogs) for the purpose of bringing medical supplies to people trapped in the mountains, and sometimes to pull them out of potentially fatal situations. The Newfoundland was developed in Canada as a large, gentle breed capable of rescuing struggling swimmers from drowning. While most dog breeds’ traditional purposes are to aid in human’s efficiency, both of these breeds are still used to literally save people’s lives.

One of the most popular uses for domestic dogs—both traditionally and today—has been to watch their home territory and alert their family members and/or attack if necessary. This comes naturally to many dog breeds as it seems to lie within the genetic repertoire of all canids. Many molosser (mastiff-like) breeds were designed to be estate guard dogs, such as the Bullmastiff, Cane Corso, Presa Canario, Tibetan Mastiff, and Fila Brasileiro. The Giant Schnauzer and Rottweiler are both large, powerful, and intelligent, so they can easily be trained to be gentle most of the time but protective when required. The Olde English Bulldogge and American Bulldog were both developed for a combination of farm/utility work and protection. The Dobermann was developed by a man who ran a dog pound in Germany and is believed to have been a tax collector at night. He wanted to create a dog with the intelligence and obedience of a German Shepherd but the athleticism of a farm dog in order to protect him from other people and dogs. He used the German Shepherd, German Pinscher, Beauceron, Greyhound, Manchester Terrier, Rottweiler, and Weimaraner to create a new breed with the specific goal of training it to attack only on command. In fact, the first dog to ever get a perfect score in Schutzhund, the working test for German Shepherd Dogs, was a Dobermann.

Another way domestic dogs have been bred to benefit humans is for police and military work. Originally, the bloodhound was the most commonly used police dog, because bloodhounds can efficiently track down fugitives and missing persons in order to pursue or rescue them. However, the German Shepherd and Belgian Malinois are the most common today. Police dogs are used for crowd control (i.e. intimidating the public during riots), search/rescue, and tracking/pursuit. Bloodhounds are still used for tracking/pursuit, but the German Shepherd and Malinois are more common for this purpose; spaniels and beagles are often used for search/rescue jobs, but sometimes shepherds; and Rottweilers, Dobermanns, and Neapolitan Mastiffs are frequently used for crowd control. Some police and military dogs are even trained to find drugs, bombs, and other illegal or dangerous substances. These are obviously not the jobs that caused dogs and humans to coevolve, but they are examples of traits in the domestic dog that have aided in human survival and efficiency over the past few centuries.