The Power of the Herd (22 page)

Horses are occasionally born with floppy ears. Some of these individuals excel in competition despite their comical appearance, but they're rarely allowed to mate. Unlike in certain dog breeds where the characteristic is valued, drooping ears are not considered cute or desirable in the equestrian world. Yet despite millennia of selective breeding, the trait still shows up now and then, lending credence to the idea that floppy ears are a universal by-product of animal domestication, enhanced by humans in some species and vehemently discouraged in others. Belyaev's research confirms this notion, taking it one colossal step further: his Farm-Fox Experiment suggests that selectively breeding generations of animals for less fearful and/or less aggressive behavior quickly gives rise to the
entire array
of physical changes associated with pedomorphosis.

Born in 1917, Belyaev was an adventurous soul, intrigued by Darwin's theories but fully capable of putting his own imaginative, informed spin on them. Like Kropotkin, he occasionally suffered for his paradigm-busting insights, but that didn't stop him for long. In 1948, Belyaev lost his job at a Moscow laboratory for standing up to an anti-Darwin Soviet scientific movement. But moving to Siberia wasn't a depressing cliché for the controversial geneticist; it was a reality that spurred him to step out to the very edge of accepted evolutionary theory.

By the mid-twentieth century, growing evidence suggested that behavioral responses in all animals were regulated by a fine balance between neurotransmitters and hormones that affected the whole organism. Belyaev took this idea and ran with it. Working in the relatively sophisticated city of Novosibirsk (known as the “Chicago of Siberia”), he found support to test a novel proposition: he wanted to see if strengthening the
behavioral
traits associated with
tamability might provoke some of the
physiological
changes associated with domestication.

So he chose the most courageous, naturally curious and gregarious foxes from a commercial fur farm in Estonia. To rule out training as a contributing factor, he kept human interaction with his test subjects to a minimum. And, as animal researchers are still prone to do, he housed them in an extremely stressful, unnatural environment — removing pups from their mothers at two months and putting them in small individual cages at three months. Even so, within a mere
six
generations, Belyaev succeeded in producing foxes that were easy to hand-feed and that would bark, wag their tails, and enthusiastically initiate contact with the experimenters. Some of these animals would whimper to attract attention, sniffing and licking their aloof caretakers like dogs begging for affection, melting the hearts of some of these scientists over time. Much more surprising was how dramatically the foxes changed physically through an experiment selecting for behavior, the low-fear and low-aggression traits that Belyaev theorized would lead to tamability and, eventually, full-fledged domestication if emphasized over thousands of years.

Only it didn't take thousands of years. Once a single scientist came up with the idea of breeding individuals with an
aptitude
for interspecies sociability, it took a mere
forty years
for a startling transformation to occur. The foxes began to
look
more like dogs, complete with curled tails, floppy ears, and striking multicolored coats offering no camouflage benefit whatsoever. The increasingly docile animals lost their musky smell, retained juvenile facial characteristics as adults, and were able to reproduce more often. Counterintuitively, selecting for behavior produced nearly
all
the physical characteristics associated with domestication,
instantly:
the thirty to thirty-five generations of selective breeding necessary to produce a hundred members of this recognizable new subspecies were literally a blip on the screen in relation to evolution.

Foxes considered truly domesticated didn't just look different, they were innately eager to please, competing with each other for the experimenter's attention when turned out in groups. Lyudmila Trut, who took over the experiment after Belyaev's death in 1985, believes their identity and continued development are now fully entwined with humans, a fact that the animals themselves understand instinctually. As she explains in her 1999 article for
American Scientist,
“Several of our domesticated foxes have escaped
from the fur farm for days. All of them eventually returned. Probably they would have been unable to survive in the wild.”

Some of these trusting, affectionate, incredibly beautiful animals are now sold as pets rather than callously slaughtered for their fur, but the move from
cage to companion is much more than a humane option for reducing the pack and raising funds for the research center. The experimenters recognize the limitations of selective breeding in a vacuum (though the first fifty years of results were unexpectedly impressive). If funding continues, Trut and her colleagues plan to study what role the fox-human bond might play in the continued evolution of this species as it moves closer to the independent classification dogs received when their wolf ancestors transformed from
Canis lupus lupus
to
Canis familiaris.
She emphasizes that

the domestic fox is not a domestic dog
, but we believe it has the genetic potential to become more and more doglike. We can continue to increase that potential through further breeding, but the foxes will realize it fully only through close contact with human beings. Over the years, other investigators and I have raised several fox pups in domestic conditions, either in the laboratory or at home as pets. They have shown themselves to be good-tempered creatures, as devoted as dogs but as independent as cats, capable of forming deep-rooted pair bonds with human beings — mutual bonds, as those of us who work with them know. If our experiment should continue, and if fox pups could be raised and trained the way dog puppies are now, there is no telling what sort of animal they might one day become.

Trut's acknowledgment of a “mutual bond” is significant. Film clips documenting this study at the Institute of Cytology and Genetics at Novosibirsk show how hard it must have been for staff members with the slightest scrap of warmth and compassion to resist their subjects' heartbreaking attempts to connect. To maintain the detachment Belyaev required, researchers had to ignore foxes reaching through the bars, crying out for attention (unlike their shy and fearful wild counterparts, who huddled at the back of those tiny wire enclosures). Once experimenters were allowed to hold and cuddle one of those furry little creatures, however, both species would have been hooked as surely as if they had been injected with one of the most potent, feel-good drugs known to man, or rather, woman. After all,
as behavior-changing hormones go, oxytocin
, released most reliably in humans when nursing babies or petting animals, is the ultimate bonding agent, one that creates a mind-altering combination of courage, focus, calmness, trust, and intense well-being, to boot.

Oxytocin both
inspires
and
rewards
connection. In part by reducing blood pressure and buffering the flight-or-fight response, this versatile hormone
activates the physical, mental, and emotional receptivity needed for mammals to approach each other. Oxytocin then ups the ante, jump-starting social recognition circuits while reinforcing “tend and befriend” behavior through a release of dopamine, which can produce feelings of elation similar to mild doses of cocaine. Some scientists believe that dopamine uses this pleasure principle as “a teaching signal” to engage parts of the brain responsible for acquiring new behavior. In oxytocin's case, it's an explicit recommendation to form strong, mutually beneficial relationships. After all, when oxytocin works its magic, the caretaker or “befriender” receives as much or more of a dopamine boost as the object of her affection.

Both sexes produce this potent chemical, but in women estrogen enhances oxytocin's power. Testosterone, which men produce at high levels under stress, seems to reduce oxytocin's effects. In the chemistry of connection, women have a marked evolutionary advantage, making a strong case for the pivotal roles that females, human
and
animal, played in forging the interspecies bonds that led to domestication.

Oxytocin bears the unique double distinction of being the very first hormone to be identified in the early twentieth century and the first polypeptide to be sequenced and synthesized, more than forty years later. The American biochemist Vincent du Vigneaud won a Nobel Prize for the latter feat in 1955, but oxytocin's relationship-enhancing benefits weren't recognized until the end of the century, when a handful of women scientists became interested in its myriad effects. For a good eighty years after the hormone was isolated in 1902, it was seen as a purely mechanistic, birth-related phenomenon causing uterine contractions and milk release. It took a breast-feeding researcher on maternity leave in the 1980s to notice how dramatically oxytocin affected a woman's behavior, emotions, and perceptions of the world.

Kerstin Uvnäs Moberg had all the right stuff to excel in the academic world: the keen logic, relentless attention to detail, and innovative leaps of thought that, when combined with exceptional endurance and ambition, helped her complete an MD and PhD, gaining her a position at Uppsala University in Sweden. She also managed to start a family during that time. Thank God she had the inclination and sheer energy to become a supermom, because her subsequent reputation as a pioneering researcher rests on her direct exposure to the powerful, mind-altering effects of motherhood.
“In pregnancy, nursing, and close contact
with my children, I experienced a state diametrically opposed to the stress I was familiar with in connection with life's other challenges,” she reveals in her book
The Oxytocin Factor.
“I was aware that the psychological
conditions associated with pregnancy and nurturing fostered something entirely different from challenge, competition, and performance.”

As Meg Daley Olmert summarizes in
Made for Each Other: The Biology of the Human-Animal Bond,
“Uvnäs Moberg returned to her lab
at Sweden's Karolinska Institute to design a series of studies that would compare the mental and physical condition of breast-feeding and bottle-feeding mothers with the amount of oxytocin circulating in their blood. She found that in addition to having higher levels of oxytocin than nonnursing mothers, breast-feeding women feel less aggressive and less anxious, as well as less suspicious and less guilty. They also enjoy greater physical ease with fewer complaints of gut and somatic anxiety and experience less muscular tension than bottle-feeding mothers.”

Uvnäs Moberg's uncommon ability to integrate the personal and scientific dimensions of her life spurred a host of studies, articles, and books on oxytocin. Her work finally legitimized the long-ignored yet intensely connective, arguably mystical states that women had been accessing, naturally, for eons. As science and technology journalist Susan Kuchinskas emphasizes in
The Chemistry of Connection,
“Many women find breastfeeding to be a deeply absorbing
, meditative experience. The world seems to drop away as a mother gazes down at her baby. She's wrapped in a profound space, and may feel an oceanic joy and cosmic connection, not only with the infant but also with everything else.”

If Sigmund Freud had lived a century later, he might have been less concerned with penis envy and more impressed with a woman's ability to mainline oxytocin. The good news is that men can experience the benefits of this wonder hormone too, and without a lot of effort — if they spend more time with women, children, and animals in ways that foster connection and affection over dominance and submission. And it is here, finally, where we begin to understand the ancient biblical preference for the pastoral lifestyle as an evolutionary force capable of balancing the more destructive tendencies of our immensely talented and incredibly dangerous species.

Over the past thirty years, studies involving rats, prairie voles, dogs, and humans have demonstrated that oxytocin makes mammals less fearful and more curious, encouraging individuals not only to form pair bonds, nest, and nurture their young but also to leave the nest and explore unfamiliar territory, most especially new relationships.
“When given oxytocin,” Uvnäs Moberg explains
, “groups of rats of the same sex become more gregarious and less afraid of contact. As aggression in the group decreases noticeably, friendly socialization
replaces it. Rather than avoid each other, the rats prefer to sit next to each other. This closeness leads in its turn to the release of still more oxytocin.”

The hormone is increased on both sides of an interaction when mothers nurse their young, when animals of any age groom, lick, or stroke each other, and when they engage in mutually desired sexual activity (as opposed to aggressive, forced encounters). As a scientist, however, Uvnäs Moberg used oxytocin injections to isolate its effects in individuals. Subsequent experiments showed ever more startling results, including elevated pain thresholds, faster wound healing, and heightened learning capacity. But she could never fully separate oxytocin's influence on an individual's physiology from the hormone's prime directive: to calm and connect with others.

As she marvels in
The Oxytocin Factor,
“Surprisingly, to a lesser degree
,
animals that live in the same cage but have not directly received the oxytocin also show the same changes.
The other animals in the cage become calmer and have lower levels of stress hormones.” Astonished by this contact-high effect, Uvnäs Moberg gave the untreated companions a drug to suppress oxytocin. Sure enough, the hormone's inherently contagious nature was blocked, suggesting that those original oxytocin-injected rats were somehow able to activate the oxytocin systems of their cage mates. Subsequent experiments showed that oxytocin's benefits could be activated in others not only through nursing and direct touch but through smell, vocal tone, and other senses.