The Why Files The Why Files --

Laying hens, milking cows: the miracle of animal breeding

Vick the dogfighter?
white, smooth-coat dog with 'tipped' ears looks off to the sidePro-football star Michael Vick stands accused of running a dog-fighting ring at his southeast Virginia property. Kennels around the area are holding, as evidence, 54 dogs taken from "Bad Newz" Kennels. News reports refer to a hard-core, violent operation centered on the bad-boy canine mascot of the hip-hop biz: the pit bull.

An American Pit Bull Terrier (APBT). Photo by Dante Alighieri at Wikipedia

Pit bull is the common name for several breeds of tough terriers. Vick was quickly suspended from the NFL, and lost major endorsement contracts with Nike and Reebok. As for the dogs, one expert described them as quite a noxious crew (see #1 in the bibliography):

"Officials from our organization have examined some of these dogs and, generally speaking, they are some of the most aggressively trained pit bulls in the country," Wayne Pacelle, the president and chief executive of the Humane Society of the United States said in a telephone interview Tuesday. "Hundreds of thousands of less-violent pit bulls, who are better candidates to be rehabilitated, are being put down. The fate of these dogs will be up to the government, but we have recommended to them, and believe, they will be eventually put down."

 Friendly brown and white dogs look at their owner offscreen
"You want to ban which breed?" two pit bulls ask while eagerly awaiting a treat. Our photographer reports that these dogs are friendly and gentle. To raise a good fighting dog, you need the right genetics, and the right training. Photo: ©S.V. Medaris

It's the pits
Pit bulls: in the annals of lavishly-loathed fidos, they rank near the top.

Sure, pit bulls can be sweet, attentive and protective, and they have devoted admirers. But pit bulls can also be killers: Combined with Rottweilers, they accounted for more than half of deadly dog attacks in 1997 and 1998 (see #2 in the bibliography).

Each year, 800,000 Americans seek medical attention for dog bites, and about 12 die.

Pit bulls and all other dogs descended from the wolf, an animal with enough genetic variation to branch out into hundreds of dog breeds that range from Chihuahua to Alsatian, from poodle and dachshund to great Dane and golden retriever.

Are pit bulls bred to kill? Not exactly, but breeding has produced an aggressive, protective and powerful dog, with jaws that are often better at grabbing than letting go. These characteristics are not an accident: pit bulls were bred to antagonize bulls in pits (hence the name).

Brown dog is half-buried in the ground. Black dog looks on, head cocked expectantly
Two Weimaraner-mix dogs dig up a rat. One of their main jobs on the farm in finding and killing vermin. The instinct to dig and kill may be genetic -- some breeds are born with it. Others learn from on-farm "colleagues" or are trained by the owner. Photo: ©S.V. Medaris

The creed of the breed?
In some localities, pit bulls are so dangerous -- or scary -- that they are legally banned, and many other localities may follow suit. We won't enter the ring to battle over the bans. But pit bulls are just one of many animals that were bred for a purpose as, over the centuries, our ancestors sought the perfect animal for food, companionship or labor.

Big white dog looks toward camera, in front of two dozen sheep, with stunning vista of hayfields in background
A Great Pyrenees at work guarding a flock of sheep. These dogs were bred to guard livestock; they typically rest during day and stay alert, barking all night, a behavior that is characteristic of the breed. Photo: ©S.V. Medaris

Breeding, or "artificial selection," produces animals with new combinations of genes, and thus can produce new body types and new behavior. Animal breeding has produced the untiring Spanish colonial horse, the trustworthy Great Pyrenees dog, and the droll Buff Laced Polish rooster. But because the process of domestication had to precede breeding, we began to wonder: How have domestication and breeding changed animals?

Tawny cock with elegant, spreading crest looks rather ridiculous!
Liberace is a Buff Laced Polish rooster. Some chicken fanciers have a bird-house full of ornamental crested breeds like this. Anybody got a keyboard and a mike? Photo: ©S.V. Medaris

Why did dogs, chickens, pigs, cows, horses, cats and catfish join our households and farms, but not lions, zebras, bison or dogfish ?


Megan Anderson, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David Tenenbaum, feature writer; Amy Toburen, content development executive

©2018, University of Wisconsin, Board of Regents.