Animals in Translation

by Temple Grandin

  Autistic people and animals are different: we can’t filter stuff out. All the zillions and zillions of sensory details in the world come into our conscious awareness, and we get overwhelmed. There’s no way to know exactly how close an autistic person’s sensory perceptions are to an animal’s. There are probably some big differences, if only for the reason that animal perceptions are normal for animals, while autistic people’s perceptions are not normal for people.

  But I think many or even most autistic people experience the world a lot the way animals experience the world: as a swirling mass of tiny details. We’re seeing, hearing, and feeling all the things no one else can.

  3. Animal Feelings

  RAPIST ROOSTERS

  We’ve been doing some strange things to animals’ emotional makeup in our breeding programs. When I was just starting my work with chickens a few years ago, I visited a chicken farm. Inside the barn where all the chickens lived I found a dead hen lying there on the floor. She was all cut up, and her body was fresh. I was horrified.

  I went back to the farmer and I said, “What was that?”

  He told me the rooster did it: the rooster killed the hen. He acted like that was a perfectly normal thing for a rooster to do. He wasn’t happy that his roosters were killing his hens; he just thought that’s the way it was.

  I knew that couldn’t be right. If roosters killed hens in nature, there wouldn’t be any chickens. But people raising animals in captivity tend to forget this basic fact of life. A lady who raises llamas told me recently that one of her males had tried to bite the testicles off another male. I told her that’s definitely not normal. If llamas bit off each other’s testicles in the wild there wouldn’t be any llamas.

  The chicken farmer told me that half of his roosters were rapist-murderers. I was stunned when I heard that. There is no species alive in nature where half the males kill reproductive-age females. There had to be something seriously wrong with those birds.

  So when I got home I immediately talked to one of my students whose family were backyard breeders. They had a small side business raising and breeding chickens in the backyard. She’d never even heard of a rooster killing a hen. Then I called my good friend Tina Widowski, who was a specialist in chickens, and she said absolutely not: normal roosters do not kill hens.

  Tina knew about the killer roosters, and she told me what the deal was. Ian Duncan from the University of Guelph in Canada had studied the roosters and had found that the rooster courtship program had gotten accidentally deleted in about half of the birds. A normal rooster does a little courtship dance before trying to mate with a hen. The dance is hardwired into the rooster’s brain; it is instinctual behavior, or what animal ethologists call a fixed action pattern. All normal roosters do it.

  The dance triggers a fixed action pattern in the hen’s brain, and she crouches down into a sexually receptive position so the rooster can mount her. She doesn’t crouch down unless she sees the dance. That’s the way her brain is wired.

  But half of the roosters had stopped doing the dance, which meant that the hens had stopped crouching down for them. So the roosters had become rapists. They jumped on the hens and tried to mate them by force, and when the hen tried to get away, the rooster would attack her with his spurs or his toes and slash her to death.

  SINGLE-TRAIT BREEDING

  The rapist roosters were a side effect of single-trait breeding, which is selectively breeding animals to increase or decrease just one or two desirable traits, like fast growth (to decrease feed costs and time to market) or heavy muscling (to increase the amount of meat per bird). The breeders focus totally on those traits and nothing else.

  Single-trait breeding isn’t quite as simple as just mating fast-growing, big-muscled males to fast-growing, big-muscled females, because when you do that fertility tends to go out the window. You get animals who have trouble reproducing themselves. So breeders mate females who have fast growth, big muscles, and sound fertility to males who just have fast growth and big muscles. They don’t worry about fertility levels in the males, because even a low-fertility male can still fertilize the eggs of a female with good fertility. You end up with a hybrid chicken, which means a cross between two different lines. All of the chicken meat and eggs we eat come from hybrid birds.

  Single-trait breeding works fast in chickens because their reproductive cycle is so short. A chicken egg has to be incubated for only twenty-one days before it hatches, and a newly hatched female chick will be ready to lay fertile eggs five months later. That’s two generations of chickens in one year, which means that in three to five years the genetic line can be changed completely.

  The problem with single-trait breeding is that when you breed for one trait you end up changing other traits, too: there are always unintended consequences. That’s what happened with the roosters.

  The rapist roosters didn’t come along until breeders had gone through at least three different single-trait breeding programs over a number of years. The first goal the industry pursued was to develop faster-growing chickens who could be taken to market sooner. They mated the fastest-growing hens with the fastest-growing roosters and voilà: faster-growing chickens. In practice it’s more complicated than this, because they also do various genetic calculations, but the basic approach is to breed fast to fast.

  Like every single-trait breeding program, this one had some unintended consequences although they weren’t as severe as the rapist roosters. Mainly the faster-growing chickens tended to have weaker legs and hearts. The weak hearts meant a higher incidence of flip-over disease, which is a nice way of saying that the chickens’ hearts gave out. Heart failure in chickens got the name flip-over disease because that’s what it looks like. When a chicken has heart failure it suddenly flips over and dies.

  The next goal was to breed chickens with bigger breasts because people like to eat white meat. That program was successful, too; they got chickens with bigger breasts. This time they got a lot more problems, though, because the chickens grew so big that their legs couldn’t handle their weight. Many of the chickens were so lame they couldn’t walk to the feeder, and some of their legs were deformed and bent, with fluid-filled swellings.

  The chickens were probably in constant pain. One study found that the lame chickens would choose to eat bad-tasting feed laced with painkillers over normal-tasting feed, which is good evidence that the chickens were suffering.

  They also had a much higher rate of flip-over disease, because their hearts were too small to pump blood to their huge bodies. It was like trying to run a Mack truck on a Volkswagen engine, and their hearts gave out.

  The big-breasted chickens were a disaster. No one wants to breed chickens who are lame and in pain, but even if you didn’t care about the chickens’ well-being, no business can sell deformed drumsticks to the food market. They had to do something, so they started breeding for strength and livability, which means the chickens’ overall health and ability to grow and thrive instead of dying young.

  They didn’t just go backward a step to the earlier chickens with the smaller breasts, because they wanted to have their cake and eat it, too. They wanted fast-growing, big-breasted chickens with strong legs and sound hearts. Breeder colonies think like software companies. If there are problems with Chicken 3.2 they don’t go back to Chicken 3.1. They go forward to 3.3.

  So in another few years they had big, strong chickens with big, heavy thick legs and stronger hearts and it looked like they had their dream chicken. Then nature threw them a curveball and they got raping, murdering roosters. No one has any idea why or how the genes for hearts and bones are related to the genes for mating behavior, but obviously they are.

  This kind of thing happens all the time when breeders over-select for a single trait. You get warped evolution.

  The really bad thing was that the change happened slowly enough that the farmers and probably the breeder colonies, too, didn’t realize they’d created a monster. Nobody noticed what was happeni
ng. As the roosters got more and more aggressive, the humans unconsciously adjusted their perceptions of how a normal rooster should act. It was a case of the bad becoming normal, and it’s a big danger in selective breeding programs. I’ve seen it many times.

  SELECTION PRESSURE

  Human beings are constantly changing the selection pressure on animals, whether we want to or not. Selection pressure is the term for what happens when the environment influences or selects which members of a species live long enough to reproduce successfully and which do not. Selection pressure can help new traits get stronger and more widespread in a species, and the absence of selection pressure can cause long-standing traits to weaken or disappear.

  That’s what happened with the Old World primates. They probably experienced some kind of random genetic mutation that gave them better color vision; then their improved color vision was so useful for finding food that the animals with the best color vision also had the best chance of staying alive long enough to reproduce. After their babies were born, of course, the trichromatic vision animals would also have had the best chance of finding enough food to feed their offspring, so the babies—many or most of whom would have inherited the new trichromatic vision mutation—also lived to adulthood and reproduced. That’s how selection pressure strengthens a trait; it gives animals who have the trait a reproductive advantage. Over succeeding generations their genes spread through the population.

  At the same time, once vision became more important for finding food, smell probably became less important. This would have meant that animals with an excellent sense of smell were no more likely to have babies than animals with a poor sense of smell: everyone could reproduce no matter how good or bad their sense of smell. The selection pressure for good smell genes was gone.

  As a direct result, Old World primates’ sense of smell would have gone into decline. Genetic mutations happen all the time when animals reproduce, due to simple copying errors in the DNA. Some mutations are good, some are bad, and some don’t make a difference one way or another. Selection pressure saves and promotes the good mutations and weeds out the bad ones. Once selection pressure is gone, a trait will go into decline through the natural process of routine genetic mutations piling up on each other until the trait or traits those genes influence has weakened or even disappeared.

  THE BAD BECOMES NORMAL

  When it comes to domestic animals, we’re the environment. We create the selection pressures. If you’re a chicken breeder and you allow only the fastest-growing roosters and hens to breed you’re exerting a selection pressure in favor of faster-growing chickens.

  That’s an example of an intentional selection pressure, but people create unconscious, accidental selection pressures all the time. For instance, you’ve probably heard doctors complain about patients not finishing their full course of antibiotics. The reason you’re supposed to finish your antibiotics is that when you don’t, you’re unintentionally creating a selection pressure that favors the development of antibiotic-resistant strains. That’s because you’ve used a half-course of antibiotics to kill off the weaker bacteria, leaving only the stronger bacteria alive to reproduce. Over several generations, that’s how you get bugs that antibiotics can’t kill.

  With domestic animals, we are the main engine of evolution. We’re constantly changing their bodies and their emotions, and it happens a lot faster than we realize. The most interesting study of this was one where the researchers gave rats from the same genetic strain to two different labs and then left them there for five years while the labs did all their normal experiments. Both of the labs bred successor generations from the original rats, which meant that researchers could compare the descendants.

  At the end of five years, the researchers tested the rats and found that the two groups of descendants had developed completely different levels of natural fear. They tested this by doing open arena studies with each rat. In an open arena study you put one rat alone inside a well-lit open space about the size of a large tabletop, and watch to see how much exploring he does. Being prey animals, mice and rats don’t like open, well-lit spaces. Only the boldest rat will do much exploring out in the open; most rats hang back at the sides of the arena and stay still.

  The ancestor rats had all started out with exactly the same levels of exploratory behavior. But at the end of just five years, one group of descendant rats was much more fearful than the other.

  The interesting thing was that none of the people at the labs had any idea their rats had changed, and none of them had tried to breed rats with different levels of fear. The two groups of rats just naturally evolved away from each other in response to different conditions at the two labs. This is what happens in unconscious selective breeding.

  The researchers don’t know why the rats evolved away from each other. They just know that they did. No one at either of the labs had any kind of agenda other than just to use the rats in normal psych lab studies, and there wasn’t any big difference in the kinds of studies the two labs were doing that could explain why the two descendant groups diverged in personality.

  My guess is that the employees at the two labs probably responded differently to aggressive behaviors without realizing it. Say I’m the lady who takes care of the rats at the first lab, and I have a couple of rats who bite—I just get rid of them, because I don’t like them. At the other colony you’ve got the same number of rats who bite, because the rats are all from the same line. But maybe in the second lab you’ve got a guy with big gloves and he’s kind of macho so he doesn’t get rid of them. Rats who bite get culled out of the gene pool in the first lab, but they live and reproduce in the second lab.

  That would make a difference in the open arena test because fear and aggression are related. Most of the time, the more fearful an animal the less aggressive he is, because a high-fear animal is afraid to get into a fight. High-fear animals can also be more aggressive under certain circumstances, which I’ll get to in a second. But overall, fear inhibits aggression. Under most circumstances, rats who bite are probably less fearful, so at the first lab, the one with the hypothetical lady culling the biters, I’m selectively breeding for fearful rats, and that’s what I’m getting. Rats with higher fear.

  That’s one possibility.

  On the other hand, say it was the macho guy who was culling the aggressive rats, not the lady. Maybe he was handling his rats roughly and scaring them. If that were the case, the rats doing the biting would be the high-fear rats, not the low-fear ones. Low-fear animals are more aggressive when fighting another animal, but high-fear animals are more likely to panic and bite when they are handled roughly by humans. If the man got rid of the biting rats he would be the one changing the gene pool by selecting for calm, low-fear animals who can take a lot of rough handling. Either way you get the same result: one lab is inadvertently breeding a different kind of rat—a more confident rat with lower fear, in this case.

  We’ll probably never know what happened, but the bottom line is that some sort of unconscious, unintentional selection pressure had to have been put on one or both lines of those rats to cause them to diverge so dramatically in just five years.

  That’s not a bad thing on the face of it necessarily, because accidental selection pressure is probably less dangerous to the animal, although that’s never been studied. At least with unconscious selective breeding the humans influencing evolution aren’t consciously trying to change just one aspect of the animal. They may be unconsciously shaping a cluster of related behaviors, or they may just be less intense about changing the one behavior (like biting) that’s bothering them. The lady at lab number one might not be culling every single rat who shows the tiniest bit of aggression, so the gene pool doesn’t get quite so distorted as it does in formal selective breeding programs.

  It’s when you consciously and purposely breed animals to change one defined physical trait dramatically from what nature intended that you can definitely end up with some major emotional and behavioral
problems. Moreover, when you’re trying to change a physical trait you very, very often end up changing an emotional and behavioral trait, too. The body and the brain aren’t two different things, controlled by two completely different sets of genes. Many of the same chemicals that work in your heart and organs also work in your brain, and many genes do one thing in your body and another thing in your brain. So if you change a gene in order to change a chicken’s breast size, you’re also going to change whatever that gene might have been doing in the chicken’s brain, assuming you’re modifying a gene that is active in both places.

  This is a very serious problem in the selective breeding of animals. Over the years I have learned that when you over-select for any trait at all, eventually you get neurological damage, and neurological damage almost always means emotional damage, or at least important emotional changes. The distressing thing is that with single-trait breeding for a physical trait, nobody notices the emotional changes that are emerging right along with the altered physical trait, because nobody is expecting to see any emotional changes. The breeders are monitoring physical changes, not looking for emotional or behavioral changes. So breeders don’t perceive how much the animals are changing emotionally until the behaviors have gotten so extreme that the alarm bells finally go off. Then they’ve got another big problem to fix.

  With the rapist roosters, the good news is that I think they probably are getting the problem fixed now. I saw some of these chickens just a few months ago, and they all behaved just as nicely as can be. I think probably the companies are culling the rapists, but I don’t know for sure, since they don’t write up and publish what they’re doing.

  PSYCHO HENS

  There was another really bad case of warped evolution with egg-laying hens up in Canada. White chickens are much more hyperactive and frantic than brown chickens, who are calm and laid-back. However, white chickens have a big advantage over brown chickens, which is that they need a lot less food to lay the same number of eggs. That’s called feed conversion. The farm I visited wanted to breed brown chickens who could lay more eggs on less food, so they crossed them with the more feed-efficient white chickens. (They didn’t want to just switch over to white chickens, because a lot of people like to eat brown eggs and only brown chickens produce brown eggs.)