Let us take a tour of how selective breeding, within their littermates, shaped the dogs we know today.
The domestic dog, through selective breeding by humans, has evolved from its wild ancestors into a staggering breadth of breeds fit for any purpose. Certainly, this was not the result of some happenstance of nature, but rather the product of selective breeding by humans. Humans have sculpted dog breeds into specific functions in life, which include everything from herding and hunting to companionship.
Dogs’ domestication is thought to be initiated between 15,000 and 30,000 years ago by people taking wolves into domestication. In this regard, people might have chosen the relatively passive wolves that were able to come closer to human settlements. These wolves then continued their life with humans over successive generations, losing some of their hostility. This represents the first appearance of wild wolves in their transformation into domestic dogs. The more these early dogs became integrated into human life, the more they were selectively bred for various roles that have included-but were not limited to-hunting partners, guards, and herders, providing the foundation for the breeds of today.
Selective breeding, or artificial selection, refers to the process in which parent dogs are selected that possess certain desired traits and then bred to produce a litter that will possess those same characteristics. This has had a great impact on the evolution of dogs, whereby humans have been able to breed them towards a wide array of functions. The Border Collie has been selected upon for intelligence and herding; it is perhaps the best sheepdog in the world. Dachshunds are bred with their characteristic long body and short legs to hunt burrowing animals like badgers.
Appearance-based breeding also became common, especially as dogs transitioned from working animals to companions. The Pug and French Bulldog are breeds developed because of their particular looks: flat faces, large eyes, compact bodies-traits that made them popular as lapdogs. Yet, most times, breeding for aesthetics often comes at the cost of health, since many such traits, like the brachycephalic structure, make them prone to breathing problems and a host of other health issues.
Dog shows and kennel clubs, which became popular during the 19th century, further refined and standardized breeds. The result was a breed standard for each kennel club-recognized breed, detailing the desired physical and behavioral attributes of breeds, thereby encouraging breeders to work towards the stated norm. This placed greater emphasis on the purebred dogs, with the breed purity in most instances being more critical than the preservation of genetic diversity.
This subsequently made several breeds more prone to genetic disorders due to inbreeding, which reduces the gene pool while increasing the chances of inherited diseases. For instance, the Cavalier King Charles Spaniel is bred for an attractive face and gentle nature but is often plagued by heart problems and syringomyelia, a painful condition wherein the skull is too small for the brain.
With times today, there is an increasing awareness of the ethical consequences of selective breeding, particularly when dog appearance becomes more important than dog health. Many dog breeders today are leaning towards a responsible method of breeding, which would mean that several modern dog breeders are concerned more with the health and welfare of dogs than adhering strictly to breed standards. Genetic testing these days is very much employed to screen hereditary diseases, and crossbreeding is resorted to at times with the hope of introducing new genetic material in order to minimize health risks.
Undoubtedly, the selected breeding that led to these breeds of dogs has enriched our relation with dogs: companions that fit our lifestyle, needs, and aesthetics. At the same time, it reminds us of the great responsibility attached to the shaping of another species. We need to further refine and develop breeds of dogs while making sure the health and happiness of our canine companions are guaranteed.
