Animals in Translation (13 page)

One genetic development I
am
concerned about, though: we're seeing more and more lameness in pigs today.

A P
UPPY
B
RAIN AND
G
ROWN-UP
T
EETH

Human selection pressure on animals' emotional makeup is probably the most obvious in dogs. I do not like what breeders are doing to purebred dogs. Breeders have made collie faces thinner and thinner, for example, leaving less and less space inside the skull for their brain. A dog needs a nice, wide skull to house its brain, and if you look at old paintings of collies from the beginning of the twentieth century that's what you see: Lassie with a broad, flat forehead.

By the early 1980s collie heads had gotten so narrow that a friend of mine who grew up with a collie on a farm in the 1950s and 1960s told me she didn't recognize the collies in her neighborhood as belonging to the same breed as her childhood pet. Somehow she got the idea that the “needle-nose collies” her neighbor owned came
from a whole different line of French collies she'd never seen before! (I don't know how she got France in there, but she did.)

The problem isn't just the reduced space for the collie's brain; it's also the weird shape of the skull. I would expect to find that the progressive narrowing of their faces has distorted collie brains anatomically. But whatever the cause, their intelligence has gone down so far that I call collies brainless ice picks. It's a horrible thing to have done to a nice, and beautiful, dog.

Making collies stupid wasn't the point, of course. Collie breeders probably just wanted to exaggerate one of the most distinctive features of the collie dog, which is its long thin nose. But in the process of breeding for super-elongated noses, they bred out a decent-shaped skull.

People probably put much more constructive selection pressures on mutts. A mutt who bites people, or who destroys the house by chewing everything in sight, has an excellent chance of being sent to the pound or put to sleep. That means his genes will be removed from the gene pool. Just about the
only
mixed-breed dogs who get to reproduce are the ones who are well adapted to living with people—and good at getting out of the yard. (I know owners are all supposed to neuter their pets, but a lot of owners don't. That's why we have so many mutts.)

With purebred dogs the selection pressures are completely different, and a lot of them are negative. For one thing the breeders are consciously trying to meet American Kennel Club standards, which are heavily tilted toward physical criteria, not emotional or behavioral. Moreover, professional breeders rarely if ever think about what their beautiful dogs are going to do to an owner's house, and they usually don't call the people who've bought their puppies to follow up on the puppy's behavior. All the puppies in a litter could have emotional or behavioral problems and the breeder could know nothing about it. So there'd be nothing to stop him from continuing to breed the parent dogs and producing more puppies with the same problems.

The other factor shaping purebred dog genetics is owners' higher tolerance for difficult behavior in a beautiful, expensive animal. A person who has spent $1,000 on a dog is going to put up with a lot more bad behavior than a person who has spent nothing. And if the
owner is planning to breed the dog he won't stop to think maybe a dog who is horrible to live with shouldn't have puppies.

This is just a theory, but there's plenty of evidence on the emotional and behavioral problems of purebred dogs versus mixed breeds to support the hypothesis that the selection pressures on mutts are more constructive. For one thing, mutts are physically healthier, because the bad traits of purebreds, such as hip dysplasia, disappear just one or two generations away from the purebred line.

Mutts are also more likely to be emotionally stable, for a couple of reasons. One is that negative emotional traits will tend to get bred out of mixed-breed dogs, because mutts with major emotional problems like aggression or severe separation anxiety are probably more likely to be sent to shelters than purebreds. The other is that no one is practicing single-trait selective breeding with mutts, so mutts are not going to be turned into monster dogs the way the roosters were turned into monster rapist roosters.

In terms of behavior, the most important difference between mutts and purebred dogs is that purebreds are responsible for the large majority of fatal dog bites, not mutts. One twenty-year survey found that purebreds were responsible for around 74 percent of all fatal dog attacks on people. Seeing as how purebreds are only around 40 percent of the total pet dog population in the country, that's pretty bad.
⁴

There have to be at least a couple of reasons for this. One, I'm sure, is that aggressive mixed-breed dogs get put down much more quickly than aggressive purebreds. But I think purebred dogs also suffer some of the negative emotional and behavioral effects of single-trait selection. Often breeders will mate their dogs so as to exaggerate one distinctive trait in the breed, like the rough collie's long thin nose. Since, as I mentioned earlier, any time you selectively breed for one trait, eventually you end up with neurological problems. Once you start getting neurological problems, one of those problems is likely to be aggression, so it doesn't surprise me that purebreds have more aggression problems than mutts.

Probably the most stable mutts are mixed-breed dogs whose underlying skin color isn't too light. Hair color doesn't matter; you just want to be sure you're not adopting an animal who has too
many albino characteristics, such as blue eyes, a pink nose, and white fur covering most of its body. A small amount of white fur is perfectly fine, but you should avoid a white or light-colored coat combined with either blue eyes or a pink nose.

The fact that mixed breeds are so much less aggressive is good evidence that the selection pressures on mixed breeds are more constructive. My impression is that mixed-breed dogs are easier to live with in a lot of ways. I don't think there's any hard data on how much shoe chewing mixed breeds do compared to purebreds, but there's a lot of anecdotal evidence that purebreds, or at least certain breeds of purebreds, do more of it than mutts.

A friend of mine told me a typical story about mutts versus purebreds on chewing. Altogether she has owned two mixed-breed black dogs, and one yellow Labrador retriever. Labs, in case you didn't know it, are notorious chewers. Even though my friend got all three dogs as young puppies, the mutts did hardly any destructive chewing at all, whereas the yellow Lab chews everything she can get her teeth on. She's destroyed shoes, toys, pencils, pens, one corner of the rug in my friend's office, the fringe on the oriental carpet in the living room, three different wooden chair legs, several T-shirts that were left lying around, two blankets, a couple of books, several Tupperware containers, a sweatshirt, all the balls in the house, and she chewed the electric cord to the dehumidifier in half. That's just the list my friend could remember off the top of her head, and it's only the indoor list. Outdoors she wrecked a $400 hot tub cover, chewed up the wood framing around the neighbor's picture window, and, back in my friend's yard, gnawed clear through the trunk of a whole lilac tree, just like a beaver. The dog is one and a half years old now, and she's still going. She's doing a little better, because they've been working on training her to chew her rawhide bones instead of everything else, and because she's a little more mature. But she's still destructive. My friend estimates she's done $1,000 worth of damage at a minimum, not counting the two rugs that can't be repaired and would cost a lot to replace.

All Labradors chew like that; it's built into their genetic makeup. Golden retrievers are probably just as bad. I don't think anyone knows why, although with Labs it may be related to their obsessive
overeating. (Although goldens belong to the same genetic group as Labs and all the other hunting dogs,
⁵
they don't overeat the way Labs do, so they may not chew for the same reasons.) I heard one owner call Labs “opportunistic eaters”—they'll eat just about anything you give them, including grapes and bananas. They love food so much you can train them to sit and heel just using little pieces of dry kibble. They are
always
hungry and will pack on the pounds if you let them eat whatever they want. I suspect it's this drive to eat that makes them need to chew everything in sight, because Holstein cows are the same way. Holsteins have been bred to eat a huge amount of feed so they can produce more milk, and they also have a compulsion to lick and mouth things and to manipulate objects with their mouths. Their behavior is so extreme that if a tractor gets left in their pen they'll lick the paint off and chew up all the hydraulic hoses. They'll destroy it, whereas beef cattle will just sniff it. Perhaps when you genetically increase an animal's desire to eat, you also increase its desire to use its mouth.

Of course that raises the question of why Labs have such massive appetites, and I don't know the answer to that. They were originally bred to be fishing dogs in Newfoundland, and they're impervious to cold and pain, so maybe the extra fat helps them stay warm. I don't know. That's why the quirks of selective breeding are so fascinating. If we knew why breeding a Lab to be a Lab also means breeding a Lab to be a compulsive overeater we might have a good idea of what causes most people to overeat, while some people can stop eating when they're full.

Getting back to mutts, I'd be surprised if any mutt ever chews things the way Labs do. Neither of the two black mutts my friend owned had her Labrador's chew-up-the-whole-house gene. Her first mixed-breed dog never chewed
anything
in my friend's house, even when he was a young puppy. The second dog went through a brief chewing period that he quickly outgrew. That dog was also highly responsive to punishment for chewing. He didn't have a strong inborn drive to chew things the way the Lab does, so he could easily stop chewing even with the haphazard “training” my friend gave him, which was mainly just to yell at the dog if she caught him chewing something he wasn't supposed to. That was all it took to get him to stop.

D
OGS
A
RE
P
EOPLE'S
O
THER
C
HILDREN
(N
EOTENY
)

The big problem with Labs is that they're permanent children. They're doing the chewing of a puppy but they're using grown-up teeth.

Humans have
neotenized
dogs: without realizing it, humans have bred dogs to stay immature for their entire lives. In the wild, baby wolves have floppy ears and blunt noses, and the grown-ups have upright ears and long noses. Adult dogs look more like wolf puppies than like wolf adults and act more like wolf puppies than wolf adults, too. That's because dogs
are
wolf puppies:
genetically, dogs are juvenile wolves.

We know this thanks to Robert K. Wayne, a UCLA researcher who has studied mitochondrial DNA in wolves and dogs. There's only 0.2 percent difference between the mitochondrial DNA of a dog and the mitochondrial DNA of a gray wolf. The fact that dogs look so different from wolves doesn't mean anything at the genetic level; they're still wolves.
⁶

Dr. Deborah Goodwin and her colleagues at the University of Southampton in the United Kingdom have done some very interesting research comparing dogs to wolves. She found that dogs who look most like wolves retain more wolf behaviors than dogs who have been bred to look as different from wolves as possible.
⁷
In other words, the more wolfie a dog looks, the more wolfie it acts. The King Charles spaniel, for instance, has lost half of the behavior patterns of wolves, and it still looks like a puppy when it becomes an adult.

I saw this up close in a dog I knew. He was a mixed-breed black-and-white dog with perfect, pointed ears and a long tapered nose, just like a wolf's. The strange thing about him was that he never, ever barked. He
could
bark, and he easily learned to “speak” (bark on command for food). But left to his own devices he didn't bark. He'd sit in the front bedroom monitoring the street, but when people came to the door he didn't launch into that crazed barking other dogs do. He'd get worked up and do a little “sneeze-bark,” but that was it. I think that was probably his wolf ancestry showing
through his dog exterior. Wolves don't bark, and neither did this wolfie-looking dog.

The King Charles study looked at the ages at which wolf puppies develop different aggressive behaviors, ranging from growling, which they can do by age twenty days, up through the
long stare,
which is the last aggressive behavior they develop, after they are thirty days old. You've probably seen pictures of wolves giving an enemy a long stare. They lock their eyes on to an animal's face and they stare fiercely. It's scary. I found a Web site written by a man who was on the receiving end of a long stare at an open zoo in England, the kind where you drive your car into a park where the animals live:

Dr. Goodwin found that the reason a dog can't do a long stare is that dogs stop developing emotionally and behaviorally at the wolf puppy equivalent of thirty days. A grown-up German shepherd can do every aggressive behavior a thirty-day-old wolf can do, but nothing beyond that age. The only domestic dog Dr. Goodwin found who could do a long stare was the husky, which looks a lot like a wolf. A Chihuahua never advances past the wolf puppy equivalent of twenty days of age, so it's even more neotenized.