The K9 Comparison—What Dogs Tell Us About Humans
We share about 97% of our genes with chimpanzees. But when Francis Crick, co-discoverer with James D. Watson of the double helix structure of DNA, was asked what unraveling the chimpanzee genome would tell us about human differences he replied: “I wouldn`t waste any American money on the chimp”.
Canine evolution, because of dog breeding, has been run in fast forward—in some cases, before our very eyes.
In an informative experiment, Dmitry Balyaev selectively bred foxes [PDF] to show neither fear nor aggression when approached by humans. But the foxes changed in more than just their behavior. They developed floppy ears, short or curly tails, an extended reproductive cycle—successive generations literally becoming more dog-like before the experimenter`s eyes—probably the result of changes in hormone levels.
And a recent study by the Max Planck Institute has demonstrated that that in certain cognitive tasks our canine best friends are more like us than are our simian nearest relatives. Fourteen-month old humans and almost any dog, but not even the brightest chimp, can use human pointing as a cue to find a food reward. Researchers Brian Hare and Mike Tomasello concluded [PDF] that this ability is heritable and due to recent selection, since wolves cannot do it.
Dog breeds provide the classic case study of within-species differentiation. Those who would dismiss race and race differences regularly point out that DNA differences between races are minimal. But , as Vincent Sarich demonstrated in Race: The Reality of Human Differences (pp. 170 – 173) human racial differences in morphology are greater than in any non-domesticated species. They are around ten times the difference between the sexes within each race and larger than the differences that distinguish the two species of chimpanzee. Despite minimal genetic differences, human physical racial differences are clearly observable.
Likewise for dogs. But only recently has genetic analysis been able to distinguish between breeds—or even between dogs and wolves.
All the differences in body shape, size, color, internal chemistry, and behavior between the hundreds of breeds recognized by the American Kennel Club, the Kennel Club UK, and the Fédération Cynologique Internationale (the World Canine Federation) are based on very few genes.
But while it`s OK to talk about differences among dog breeds, not so for human races. Unfortunately, this has been true even in scientific circles. And that in itself is instructive.
The classic study was carried out by Daniel G. Freedman for his doctoral dissertation. Freedman spent every day and evening rearing four dog breeds—Beagles, Wire-haired Fox Terriers, Shetland Sheepdogs, and Basenjis—from age two to twelve weeks.[See Constitutional and Environmental Interactions in Rearing of Four Breeds of Dogs D. G. FREEDMAN, Science March 14, 1958 (Pay archive)]
He noticed that as soon as their ears and eyes opened, the breeds differed in behavior. Little Beagles were friendly from the moment they detected him. Shetland Sheepdogs were the most sensitive to a loud voice or the slightest punishment. The Wire-haired Fox Terriers were so tough and aggressive, even as clumsy three-week olds, that Freedman had to wear gloves in playing with them The Basenjis, barkless dogs from central Africa, were aloof and independent.
Many of today`s breed differences are cosmetic. But originally breeds were selected to excel in certain elements of the basic wolf-dog ethogram [behavioral repertoire] and reduce or eliminate others. All of these differences, including the barklessness of the Basenji, make perfect sense in terms of what we know about the traits for which the different breeds were, or were not, selected.
Beagles are scent hounds. They run in packs and use their sense of smell, which is better than that of almost all other breeds, to track fox and other small game.
They have been selected not only for increased olfactory tracking ability, but also diminished aggression. Beagles are a band of brothers (often literally). They all have a job to do. They are usually kenneled together, and howl to other members of the pack when finding a scent or needing help.
Fox Terriers come in two varieties, Wire-haired and Smooth-haired, but this is largely a cosmetic difference. Like Beagles, they were bred for fox hunting, but their job is quite different. The Fox Terrier literally gets a free ride in the hunter`s saddlebag—at least, that is, until the fox, as they say, “goes to earth”. No fun that for the hunters because it ends the chase and their chance to bag the fox. Game to the fox…or so it would seem.
But this is where the terrier earns his seemingly free ride and free lunches. The hunter grabs him by his short tail and hurls him to the ground. His job is to run into the den and convince the fox to resume the game by “making him an offer he can`t refuse”.
No beagle in his right mind would want any part of this. Terriers, on the other hand, are born scrappers. There is a reason why we have the expression “a pack of hounds”, but not “a pack of terriers”. Rather than a peaceful assembly the latter would quickly become a canine gladiatorial.
Even the smallest terrier, like the Jack Russell (made famous by the TV shows Frasier and Wishbone) thinks nothing about taking on a Rottweiler or a Pit Bull. Hence another dog saying: “It`s not the size of the dog in the fight, but the size of the fight in the dog”.
Among terriers, “two`s company, three`s battle royal”. Many people have purchased Jack Russells, thinking they`ll have a companion like the one on TV, only to find they`ve brought a canine Mike Tyson into their house. (With its recent popularity, breeders have started to select for less aggressiveness in the Jack Russells. Dedicated fanciers of any breed will tell you the worst thing that can happen is for it to become popular overnight because of some movie or television show. The heightened demand is met by the unscrupulous “puppy mills”. And even a dog from a reputable breeder can end up with an owner or family totally unsuited for him.)
The third breed in Freedman study: the Shetland Sheepdog, often affectionately termed “Shelties”, or incorrectly, and to the great annoyance of their owners, “Miniature Collies”. They are indeed sheep herding, not sheep protecting, dogs.
The Sheltie motto is “herd ` em, don`t hurt `em”. They have been selected for being very responsive to commands from humans and for inhibiting the part of their wolf ancestry that says “look at all that nice mutton, here for the taking”.
Shelties are excellent dogs for obedience training and competition. When I took my Great Dane, Payce, to K9 obedience school he was the second-best pupil in the class. A Sheltie was Number 1.
One of the most basic behaviors taught in obedience school is for the dog to walk alongside the handler and stop and sit as soon as the handler halts, its front paws parallel with the handler`s toes.
Payce had no trouble learning to sit. At 127 pounds and over 6 feet tall when he gets up on his hind legs, however, it wasn`t that easy for him to put on the brakes and stop on a dime. The Sheltie almost always stopped and sat dead even with her handler.
Then one time the Sheltie goofed and ended up about six inches out in front. She looked around, and quickly backed up until her front paws were dead even with her handler toes, hoping he wouldn`t notice—very much as I had in basic training, hoping to avoid the gaze of the drill instructor.
Everyone in the obedience class noticed the Sheltie`s miscue and attempted cover-up. The instructor—quite unlike my DI—pointed to it gleefully as an example of just how much the dogs can learn. Shelties been selected for both canine IQ and canine conscientiousness.
Fourth in the Freedman study: the Basenji.
Basenijis are more recently domesticated than most of the better-known breeds. Like wolves, they have never added barking to their behavioral repertoire. (Barking may be an exaggeration of the pup calling to its mother which human selection has enhanced as a means of dog-master communication).
With their tails carried up in a corkscrew, Basenjis belong to a group called pariah dogs, which includes semi-domesticated breeds around the world. (When humans cease selective breeding of dogs, the distinctive breed traits disappear, the surviving dogs take on a pariah-like appearance and the full wolf-canine behavioral repertoire resurfaces.)
Basenjis do not lack canine IQ, but they are at the opposite pole from the Shelties in conscientiousness. They don`t like taking orders from their owners. They are born canine scofflaws.
In another classic study, experimenters put some dog chow out for the pups and told them “No!” Then they would leave the room to observe the pups through a one-way mirror to see if they would go for food. If they did, the experimenter would go back into the room and scold them “No!” while also swatting them on their backside, painlessly, with a newspaper. [Genetics and the Social Behavior of the Dog, By John Paul Scott and John L. Fuller]
Shelties are so given to inhibiting, they wouldn`t touch the food. Some of them even had to be hand-nursed back into feeding again. Basenjis, on the other hand, started to chow down the minute the experimenter turned his back, before he even left the room.
A third study compared the same four breeds in getting through a series of increasingly difficult mazes. The breed differences were not in the ability to master the mazes (a rough measure of canine IQ) but in what they would do when placed a maze they couldn`t master.
The Beagles howled, hoping that another member of their pack would howl back and lead them to the goal. The inhibitory Shelties simply laid down on the ground and waited. The pugnacious Fox Terriers tried to tear down the walls of the maze. The Basenjis saw no reason to play by the rules and began jumping over walls of the maze.
But what does this have to do with humans? Professor Freedman wrote that
“I had worked with different breeds of dogs and I had been struck by how predictable was the behavior of each breed. A breed of dog is a construct zoologically and genetically equivalent to a race of man. To look at us, my wife and I [Freedman is Jewish; his wife Chinese], my wife and I were clearly of two different breeds. Were some of our behavioral differences determined by breed?” [Human Sociobiology: A Holistic Approach]
Freedman and his wife set about designing experiments to test that hypothesis. Their story is interesting not just for its scientific results and for the different receptions they received in even the most prestigious scientific journals.
The Freedmans decided to observe the behavior of newborns and infants of different races using the Cambridge Behavioral and Neurological Assessment Scale. Unlike the typical reflex tests performed by pediatricians, these tests, called the “Brazelton“ after their developer, measure social and emotional behavior. [The Manner Born: Birth Rites in Cross-Cultural Perspective, Chapter 13, Ethnic Differences in Babies]
The Freedmans found that European American and Chinese American newborns reacted differently even though hospital conditions and prenatal care were the same.
White babies started to cry more easily, and once they started, they were more difficult to console. Chinese babies adapted to almost any position in which they were placed. When placed face down in their cribs, they tended to keep their faces buried in the sheets rather than immediately turning to one side, as did the Whites.
In a maneuver called the “defense reaction” by neurologists, the baby`s nose was briefly pressed with a cloth, forcing him to breathe with his mouth. Most Caucasian and black babies fight the maneuver by immediately turning away or swiping at the cloth with their hands. Not surprisingly, this is listed in Western pediatric textbooks as the normal, expected response.
But not so the average Chinese babies in the study. They simply lay on their back, breathing from the mouth, “accepting” the cloth without a fight.
There were other more subtle differences. While both Chinese and Caucasian infants would start to cry at about the same point in the examination, especially when they were being undressed, Chinese babies stopped crying immediately, while Caucasian babies quieted only gradually.
The Freedman noted that the film of their finding left audiences awestruck by the group differences.
They then tested Navajo babies. Anthropology, linguistics, and DNA agree that Amerinds have a relatively recent Asian origin. And the behavior of the Navajo babies was indeed like that of the Chinese-Americans, not the Whites.
Freedman submitted the paper on racial differences in neonate behavior to Science, the most prestigious scientific journal in the U.S. It had published his study behavioral differences in pups of different dog breeds without any problem or controversy.
The paper on race differences, however, was rejected by a split vote of the reviewers.
Freedman then submitted it to Nature, the British analogue to Science. It again received a split decision from the judges. Fortunately, the editor broke the deadlock by casting his deciding vote in favor of publication. [Behavioural Differences between Chinese–American and European–American Newborns D. G. Freedman & Nina Chinn Freedman, Nature December 20, 1969]
Freedman`s studies are important because they used a comparable experimental design for humans and dogs. And although our society does not automatically consider being more or less active as being better or worse, unlike IQ, differences, race differences in behavior among humans were viewed even by scientists as too hot to handle.
Breed differences are taken for granted in the Veterinary Drug Handbook (analogous to the Physician`s Desk Reference). Two examples
The active ingredient in the most commonly prescribed medicine for prevention of heart worms, it is quite safe used in the proper dosage, killing the parasites without having any adverse effect on the dog—except for Collies, Collie-like breeds, and Collie-mixes. For them, the same amount of Ivermectin that wouldn`t faze a Chihuahua can be fatal.
This ultra-short acting tranquilizer is potentially lethal for greyhounds, whippets, and similar breeds. The lightly-built coursing and racing dogs carry more muscle and much less fat than other breeds. Fat is able to take up more barbiturate than muscle. Coursers take much longer to metabolize the drug in their system. Veterinarians use different tranquilizers
Does race have any place in human medicine? The answer increasingly is “yes”.
African American patients, on average, do not benefit as much as whites from ACE (Angiotensin Converting Enzyme) inhibitors, a standard treatment for heart failure.
This is probably because of race differences in nitric oxide, which is produced by the cells that line our blood vessels and dampens contraction of the muscle cells, relaxing the vessels and lowering blood pressure. Blacks are more likely than whites to have nitric oxide insufficiency. Why, no one currently knows.
Jay N. Cohn, a professor of medicine at the University of Minnesota School of Medicine, has patented a drug called BiDil which is a combination diuretic and vessel dilator that replenishes nitric oxide. The Food and Drug Administration authorized the testing of BiDil, the Association of Black Cardiologists has recruited patients, and the Congressional Black Caucus has supported the project. And with good cause—Blacks have twice the rate of heart failure as whites, and those afflicted are twice as likely to die.
Isoniazid was introduced soon after the end of WWII to combat tuberculosis. It was soon found that the drug was not very effective in Eskimos because they have a variant enzyme which metabolizes the drug so rapidly that it never has a chance to be effective.
At least in medicine, humanitarianism and common sense are increasingly trumping ideology for humans as well as for dogs.
The take-home lessons from our brief look at ourselves, our best friends, and our nearest relatives are:
- Small DNA differences can produce large and significant differences in body shape, size, internal chemistry, and even behavior and cognition.
- Changes in all three are often linked because of the action of a small number of “regulator” (master) genes.
- When the selection pressure is high enough, changes can take place in a very short time—the stronger the pressure, the less evolutionary time required
- These differences can be of vital importance in both human and veterinary medicine—and in human behavior.
One can only hope that we can learn to handle group differences in humans as intelligently and humanely as we do those in dogs.
© Copyright Frank Miele 2008. This article is adapted and updated from Race: The Reality of Human Differences by Vincent Sarich and Frank Miele.
Frank Miele [Email him] is also the author of Intelligence, Race, and Genetics: Conversations with Arthur R. Jensen and The Battlegrounds of Bio-Science. He is a senior editor of Skeptic Magazine