Lentis/Unnatural Selection: Explaining Strange Pet Breeds

Animal companionship has been a part of societies for thousands of years. However, it was only recently that people started breeding animals for their desired characteristics. Now there are more than 400 dog breeds in the U.S. with 152 recognized by the American Kennel Club, a number that is continually growing as new traits become more popular and older traits fade away.[1] In the past owning a pet has been a symbol of being elite and wealthy while over time it has come to represent stability and respect. Today sixty-five percent of U.S households own a pet and twenty-eight percent of dogs and twenty-nine percent of cats owned come from breeders.[2] This article will begin with a brief history of selective breeding and pet ownership. It will then look at health concerns associated with breeding and analyze the social values that influence popular breeding practices.

A spaniel holding sticks.


Bastet was an ancient Egyptian goddess.

Selective breedingEdit

Animal breeding to produce offspring with desired traits has been around for hundreds of years. Robert Bakewell of England pioneered selective breeding in the 18th century to choose the most desirable characteristics of his livestock, selecting larger sheep with longer more glossy wool over the others. Near the end of the 18th century more people began following Bakewell's selective breeding practice and herdbooks were created to record information about animals and prove they were of a certain breed. Charles Darwin's theory of natural selection was inspired by Bakewell's practice of selective breeding. After studying the large transformations demonstrated by Bakewell's human selection, Darwin speculated about the potential changes natural selection could bring about over long periods of time. In an essay in 1844 Darwin wrote, "Let this work of selection, on the one hand, and death on the other, go on for a thousand generations, who would pretend to affirm it would produce no effect, when we remember what in a few years Bakewell effected on cattle and Western on sheep, by this identical principle of selection."[3]

Pet ownershipEdit

In ancient times pets were owned only by the noble. Though in most cultures the lower class owned animals for hunting and working purposes, companion animals were reserved for the upper class. As shown in the picture to the right the Pharaohs of ancient Egypt often owned cats.[4] Chinese Emperors would keep dogs that were breast-fed by nurses and tended to by servants when they grew up.[4] The noble class in Rome would also keep animals such as dogs, cats, and birds. In the middle ages the aristocrats would keep small lap dogs. However the church looked down upon keeping pets as they thought animals were strongly associated with paganism. In fact during the witch trials of the 16th and 17th century, owning a pet was considered a symbol of Satan and of their guilt.[4] It wasn't until the late 18th and early to mid-19th century when pets started to become a common occurrence in the homes of the middle class. This was partially because of a decline in the need for animals to do work and a rising middle class that was now able to afford a companion animal.[5] Since then household pets have become common around the world and are an integral part of our society.

Why people breed petsEdit


Originally, people often kept pets to help perform simple tasks for their owners. For example, the German Shepherd breed was originally kept around to herd sheep on a farmer's land and Dachshunds, which translates loosely to Badger Dog, were bred to hunt small burrowing animals[6]. However, the utility of pets has changed over the course of human history, even in recent years. The average pet owner doesn't buy a Dachshund with the intent to use it to hunt badgers in the wild. Similarly, the average person doesn't have a flock of sheep in their backyard that needs herding by their German Shepherd. This doesn't mean that pets don't have utility anymore, it simply means that what they were originally bred for is almost to the point of useless for the average person. The utility of most dogs in modern times now ranges mostly from a household watchdog to a form of personal exercise[7].


In some cases, pets are also bred for entertainment purposes. Dog shows have been a tradition for the American Kennel Club since the late 1800s, which have contributed strongly to the changing characteristics of dog breeds. There are so many strict regulations on what the judges look for in these dog shows, such as the straightness of the spine or the overall shine of the coat, that breeds often experience radical changes due in part to specific breeding for these shows[8]. In fact, when some dogs were bred to try and achieve a certain color of fur, the dog breed ended up having serious back issues that is still prevalent to this day. Dog shows are not the only form of entertainment, this is also very common in Equestrian Eventing and Dressage as well as shows similar to the AKC Dog Show for different animals.


Arguably the most important part in modern dog breeding, companionship is a major consideration in modern pet breeding. Compare the general characteristics of a pet dog to that of a wolf and try to notice the differences. You'll see that a lot of pet breeds have floppy ears, which is rarely, if ever, the case in wild wolves. You'll also notice that pet dogs have bigger heads, bigger eyes, large patches of multi-colored fur, and also softer fur. This is mostly due to the fact that humans have been breeding dogs to be objectively cuter, and therefore more approachable. As breeds of dogs have evolved from their wolf counterparts, the more approachable they became, the more humans felt safe having them around. In recent years, this idea has only grown stronger. Sometimes, like with the case of floppy ears, these changes happen on accident, while other times they are the result of purposeful selective breeding[9].

Responsible breedingEdit

Responsible breeding of animals aims to enhance a desired trait or traits, and produce healthy animals in a safe environment. This involves extensive knowledge of animal breeds, animal care, and genetics. Organizations such as the ASPCA and the American Kennel Club detail breeding practices that should be followed to ensure a healthy litter. The American Kennel Club has adopted the motto that responsible breeding should always "Breed to Improve [10]." Screening is a key component of a responsible breed. Potential breeding candidates must be screened for heritable diseases and disorders, aggression, and socialization. Most breeders also screen potential new guardians to ensure the animal will be brought into a clean, safe, and loving environment. Other general guidelines followed in responsible breeding include considering the mother's age, health, and recuperative abilities, avoiding inbreeding, proper weening, and providing new parents with a full history of care and vaccination. [11]

Controversy and issuesEdit

Health concernsEdit

Manx Cat

The number of genetic disorders that many bred animals face has become more prevalent as knowledge and technology surrounding DNA has evolved. The Kennel Club in the UK has identified 396 heritable diseases that are increasingly harder to avoid as selective breeding continues[12]. In some cases, by enhancing certain traits in a breed, other less desirable traits are also enhanced. The Manx cat is a breed that has little to no tail. The animal's short backside makes Manx cats prone to spina bifida and other spinal disorders [13]. Similarly, through selective breeding, the St. Bernard has increased in size and fur in the past 100 years. This causes the dog to overheat quickly, and regularly develop disorders such as hemophilia and osteosarcoma [14]. The deterioration of health in selectively bred animals has caused individuals and organizations, such as PETA, to speak out against the practice [15].

"Ruining" of breedsEdit

German Shepherd

Some feel that selective breeding in search of friendly, compatible pets, has ruined certain animal breeds. The ruining of a breed, though less drastic than an animal's compromised health, is used as an argument against the ethics of breeding. A breed may be considered ruined if over the past 100 years, overall athletic ability or energy has declined, or habits seen as undesirable have been developed. The German Shepherd is an example of a ruined breed, since through years of selective breeding, the dog has lost its jumping abilities and developed a sloped back. The Bull Terrier is another example of a ruined breed, since the dog is regularly susceptible to excessive tail chasing. [14]


[3] Robert Bakewell (1725-1795), pioneer animal breeder, and his influence on Charles Darwin.[1]

  1. http://www.iii.org/fact-statistic/pet-statistics
  2. http://www.aspca.org/animal-homelessness/shelter-intake-and-surrender/pet-statistics
  3. a b Robert Bakewell (1725-1795), pioneer animal breeder, and his influence on Charles Darwin.
  4. a b c http://www.pedigree.com/all-things-dog/article-library/the-evolution-of-pet-ownership.aspx
  5. http://thepetwiki.com/wiki/History_of_Pets
  6. http://dogtime.com/dog-breeds/dachshund#/slide/1
  7. http://well.blogs.nytimes.com/2011/03/14/forget-the-treadmill-get-a-dog/?_r=0
  8. http://www.showdog.com/help/topic.aspx?id=17
  9. http://abcnews.go.com/Technology/dogs-floppy-ears/story?id=24635908
  10. http://www.akc.org/dog-breeders/responsible-breeding/
  11. http://www.aspca.org/about-us/aspca-policy-and-position-statements/position-statement-criteria-responsible-breeding
  12. Farrell, L. L., Schoenebeck, J. J., Wiener, P., Clements, D. N., & Summers, K. M. (2015). The challenges of pedigree dog health: Approaches to combating inherited disease. Canine Genet Epidemiol Canine Genetics and Epidemiology, 2(1). doi:10.1186/s40575-015-0014-9
  13. http://www.ufaw.org.uk/cats/manx-manx-syndrome
  14. a b https://dogbehaviorscience.wordpress.com/2012/09/29/100-years-of-breed-improvement/
  15. http://www.peta.org/about-peta/why-peta/responsible-breeders/