The Moral Lives of Animals


I first became interested in the problem of animals about twenty-five years ago. At the time, I imagined "the problem of animals" to be the problem of animals going extinct, and I set out to learn why. I had been a literature student, a scholar and reader of great books, but if literature is a fair reflection of the human mind, then animals are just about absent from it. In any case, I had already spent so much time navigating the gloomy labyrinths of formal education that I was finally handed a Ph.D. degree and shown the door. So that was enough, and I did not take this new interest in a new subject back to old places. Rather I took it in a delightfully contrary direction: to the sunny outdoors, first to the woods of southeastern Brazil and the Brazilian Amazon and then down the Amazon River in a small boat, where I swung sybaritically back and forth in a hammock, puffed lazily on a big cigar, and considered methodically the map spread open on my lap.

I was on a quest. Financed by a pocketful of credit cards, I was traveling around the world. First stop: South America. Then it would be on to Africa, Madagascar, India, and various spots in Indonesia and Malaysian Borneo. I intended during my extended circumnavigation to find the world's dozen rarest and most endangered primate types and learn at first hand why they were going extinct.

It was the sort of thing bird watchers do. I had put together my own master list of rare and endangered primates. I had already found individuals from two of the most highly-endangered monkey species in southeastern Brazil, watched them, took some snapshots with my little camera, jotted down impressions in my little notebook, and checked those two off the list. Now here I was looking for number three. I was hoping to sight individuals from a type of beautiful, black, puffy-tailed and large-bearded monkey known as the southern bearded saki. At the same time that I wanted to find those elusive little creatures, however, I also intended to consider them in context, to learn more generally about why they were so endangered. These were the most endangered monkeys of the entire Amazon Basin, an almost unconceivably vast and diverse region that contains numerous different monkey types, of which about half were in trouble. But why? And why was this southern bearded saki in the worst shape of all? The answer to those questions, I knew, would be at least partly connected with knowing why and how the Amazon forest itself was under serious threat.


Such larger issues had brought me, in a brief detour, to the geographical navel of the Amazon Basin, the seedy river-port city of Manaus, where I located the offices of a group of biologists working on something called the Minimum Critical Size Project. I had already written to someone in this group and gotten myself invited on one of their expeditions into the rain forest, where they were conducting various individual research projects while monitoring the rates of biodiversity disintegration—in plain English, species loss—occurring when certain-sized sections of rain forest are turned into ecological islands surrounded by seas of burned-out and cleared-over cattle ranch.

Soon I was bouncing in a Jeep across muddy roads and through the moonscape of cattle ranches—rough grass and stark sunlight, some languid cattle, a few industrious cowboys on horses, ten thousand dead trees, ten billion excited termites—out to the great Amazon rain forest. Once inside the forest, we set up camp on a bit of higher ground surrounded by a wealth of flora and fauna. This little expedition included me, an entomologist, an ornithologist, and two worker-porter-cook-assistants, and our camp consisted primarily of hammocks strung between poles beneath a plastic roof. During the day, the entomologist occupied himself with chasing termites, while the ornithologist was hoping to study the feeding behavior of a particular bird. First, though, she wanted to understand the fruiting cycle of the bird's favorite fruit, which appeared very high up in a big tree known as Clusia grandiflora, so her days were spent chasing Clusia grandiflora.

Rita Mesquita was her name. She was a small, very attractive young woman with arched dark eyebrows and black hair kept under partial control with a lavender loop of twine. She spoke Portugese in quick, dramatic, often hilarious bursts to her assistant and English in slow, staid, semi-grammatical productions for my benefit, and I followed her and the assistant around as they walked from one Clusia grandiflora to the next. She had found thirty-two such trees. She had marked out a whole complicated maze of routes to reach them. She had a compass and a plastic-covered map of the routes to keep from getting lost, and thus she would check the compass, consult the map, then walk very fast to the next Clusia grandiflora. Stop directly beneath the tree. Pull out her binoculars. Bend her neck way, way back and look almost straight up into the top of the tree where the fruits were revealing themselves in various stages of ripeness. She took notes, gathered and bagged fruit samples from the ground, considered her compass and map, and then we were off to find the next Clusia grandiflora.

So it was in the company of a beautiful Brazilian ornithologist that I had my first experience walking and camping inside the Amazon rain forest, and I loved it. The place was stunning: giant trees and a high canopy of shivering leaves, bursting plants, and obscure animals; knotted vines, dropping lianas, and the occasional beautiful bright flower appearing where you least expected it; a vast dynamic of light and space and glowing color. Those were the glories of the forest. The dangers I more slowly came to recognize—starting, perhaps, when I made my first solo foray out of camp in order to answer the urges of nature and modesty simultaneously. I walked away from my companions for perhaps forty paces, reaching a place where I could no longer see them, or they me, and a few steps later I found a spot where I was suddenly no longer certain where I had just come from. I had begun to lose my orientation, in other words, and thus I became appropriately concerned that I would soon be lost followed by dead.

The sun was directly overhead. The high, dense, and complex canopy blocked most direct sunlight in any case. There were enormous trees and many other kinds of vegetation all around me, but even if I could have recognized this or that species of trees, I would never remember individual trees. The terrain was monotonously rolling, an endless roller coaster of ups and downs with no signature irregularities. Nor were there any orientation clues down on the forest floor; and now, looking up and looking around, I felt like an insect trapped inside a big bottle. I may have wanted to keep on walking, but did I have any idea where I was headed? Rita Mesquita had marked out her trails connecting the Clusia grandifloria trees. She routinely referred to her map of the trails. She regularly consulted her compass. I could only refer to and consult with her.

I called out. No answer. I called again. She called back. And in that way I soon found my way back to camp again. But I had just learned my first critical lesson about the Amazon rain forest: You do not go into such a place alone. The problem is not poisonous snakes, ferocious carnivores, pernicious pathogens, or any other kind of aggressive biological entity. The problem is orientation.


One essential quality of a tropical rain forest is diversity, an intensely-concentrated crowding of species. On average, a four-square-mile piece of tropical rain forest will contain 100 species of reptiles, 125 species of mammals, 150 of butterflies, 400 of birds, and roughly 42,000 of insects. But the flip-side of diversity is dispersion. You might find a hundred different tree species in a two-and-a-half acre patch of the Amazon, but walk half a mile distant, examine a comparable-sized patch, and you'll find that half the tree species are new. The principle of dispersion works on a larger scale, too. The Amazon forest, for example, might actually be considered as eight different forests, eight very distinctive assemblages of plant and animal types.

So species are intensely plentiful but spottily distributed in a tropical forest. In terms of monkeys, the full Amazon is home to a large number of species. Let's say that number is thirty. But you'll never find all thirty in one area. One species will inhabit a comparatively small triangle of swamp forest six hundred miles in that direction, another may be living along an elongated strip of riverine forest right in front of you. A third will be found in a somewhat larger patch of terrestrial forest a few hundred miles over in that direction.

Here's where the boat, the hammock, the cigar, and the map spread open on my lap come in.

The boat was necessary because the monkeys I was looking for, the southern bearded sakis, happened to live in a patch of forest about 750 miles down river from Manaus. Boats in the Amazon Basin are like buses elsewhere, so you might imagine I had purchased a ticket for the Greyhound and was taking a cross-country trip in the USA.

The hammock was essential for sitting and sleeping. I was traveling on the open lower deck of this vessel, lined up alongside maybe two dozen other people, all local Brazilians, with another couple dozen lined up in their hammocks on the other side. I strung my own hammock between a pair of hooks established for just that purpose, wrapped myself in it at night and snoozed like a butterfly in a cocoon, and, during the day, relaxed more openly on it. From that vantage point, I could watch the brown and churning water move in one direction and the green and hazy shore pass by in the other.

The cigar? This was an open-air vessel with constant cross-winds, and I was still insensitive enough to smoke around others and immature enough not to think deeply about the relationship between tobacco and life expectancy. Also, while my Spanish was only minimally functional in a Portugeuse-speaking country, I found that passing out cigars to some of my fellow passengers was its own sort of friendly conversation.

The map spread open on my lap would help with orientation—although, actually, I carried several maps of three different sorts. First, I had a star map of the Southern hemisphere, given to me by an astrophysicist friend from the Northern hemisphere. I always had trouble making sense of that map, in part because when the thing could be most useful it was always dark. Still, the star map and the stars above, sparkling like white diamonds in black velvet, provided me with an important kind of macro-geographical orientation—as I looked at a piece of the universe from a new perspective and watched, for example, the Southern Cross rise up towards the middle of the night's black dome. Also, the star map and stars gave me some emotional orientation. I was often lonely. I sometimes comforted myself by finding the pieces of sky I knew were pieces of the sky someone could easily make out back home.

Later on, I began to see that the star map and stars also provided an orientation in time. Now that I had embarked on my global monkey chase, I wanted to consider time in the big way, the way evolutionary biologists do, and I imagined that the stars might help. We commonly imagine that the stars are utterly unchanging, permanently fixed in their positions. Stars appear to be at one with eternity—but of course they are not. As the universe expands, the hurtling stars within it are slowly shifting their positions in relation to one another. Edmond Halley, remembered as the man who discovered a big comet, was the first astronomer to note that even since the time Ptolemy had carefully charted his own star map, a mere fourteen hundred years earlier, some of those celestial bodies had changed position. In a similar fashion, the stars making up the Big Dipper will have shifted their positions enough that within another 200,000 years, more or less, that constellation will have to be renamed. Let me be the first to suggest it: Big Frying Pan.

The constellation Orion the Hunter can be identified partly by the faded red star marking his right shoulder, Betelgeuse, which is an ancient dying star: red because it has become comparatively cool, large because its gravity has become relatively weak. Betelgeuse is 75 million years old, but most of the other stars making up this constellation are white-hot whipper-snappers, including the white diamond Rigel marking Orion's left foot. Rigel may be only two to three dozen million years old.

Thinking like an evolutionary biologist, as I was trying to do, requires orienting oneself within that sort of time frame. The ecosystem we now describe as the great Amazon rain forest began around 75 million years ago, meaning that the forest I was then sliding past was a contemporary of Betelgeuse. The primates I was looking for began as a scurrying, furtive group of mammals around 65 million years ago, long before the birth of Rigel—but soon after a giant asteroid struck the earth, exploded, and raised a dark cloud. With the sunlight shuttered for a season or two, that dark cloud pretty much wiped the slate clean: extinguishing the last of the big dinosaurs, for example, and enabling some small mammals to began flourishing in newly-attractive environments in the trees. Those became the first primates.

I find thinking with that sort of time-orientation reassuring in some ways but distressing in others. After all, the changes we ordinarily conceptualize as happening somewhat gradually—such as the ten-fold expansion in human numbers since, say, the publication of Herman Melville's big whale book, Moby-Dick (1851), and the appearance of a billion gasoline-burning, carbon-dioxide-emitting automobiles in our own era—are from a biologist's perspective occurring with the speed and violence of an exploding asteroid. Politicians, who ordinarily look through a time-window about four years wide, should speak more often to biologists.

The other two kinds of maps I carried and would sometimes spread out on my lap were useful for geographical orientation. First there was my big map of South America, good for tracing the vermiculate curves of the Amazon and identifying a few of the more salient villages and towns I was passing and the big city, Belém, I was bound for.

The river, of course, always provided a general sort of orientation. The current flowed forever towards the Atlantic. The boat was efficiently aligned with that current in the style of a compass needle aligned with the earth's magnetic field. Sometimes the river was so wide I could hardly make out the far shore. Sometimes we passed so near to shore that I could almost step off onto dry land. And regularly we came up to a landing, a village or town, and unloaded boxes and bags, dropped off passengers, and then uploaded other passengers as well as food and fresh fish. But usually the village or town would have a name posted on a sign somewhere, and so I could refer back to the map. That map was useful in a reassuring sort of way for charting our progress, counting off the days. After about three days, in fact, my floating bus pulled up at the small city of Santarém, half-way down; and I waited in Santarém for a couple more days before catching another Greyhound all the way down river to the big city of Belém, at the mouth of the Amazon.


In Belém, my final map came into its own. This was something entirely different from my South American map, with its childishly bright colors and dot-matrix splatter of cities and towns and sometimes villages, its squiggling rivers and the mostly straight lines demarcating national borders. This was a much smaller and more subdued map of another world with an alternative set of national boundaries defining the territory of the southern bearded sakis. It was a primate distribution map, one of several I had photocopied from a wonderful book, Primates of the World (1983), put together by Jaclyn Wolfheim. Wolfheim's encyclopedic work identified all the world's primates (monkeys, apes, and prosimians—such as lemurs) and described where they were, what they did, how they lived, what and who they ate, who ate them, how their societies were structured, and so on. The book also provided a distribution map for each primate type that marked out, while identifying standard rivers and other markers, the species' territorial boundaries. I was fascinated by Wolfheim's distribution maps and carried several of them with me on this trip. And now, having arrived in Belém and rested overnight in a dodgy hotel with little peepholes neatly drilled into the doors and walls, I wandered through the city until I had located South America's most important tropical botany, zoology, and anthropology research institute, the Museo Goeldi. There I found a helpful American-born ornithologist named David Oren and showed him my distribution map of the southern bearded saki.

Oren studied the map. He showed me some moth-balled skins and skulls of these monkeys kept in drawers at the museum. And, after some discussion and more consultation with more maps, he suggested that I might find still-living monkeys if I traveled west and then south from Belém, up a tributary of the Amazon—the Tocantins River—for a day and a half until I reached the old village of Tucuruí. On the far side of that old village I would find a gigantic hydroelectric dam, and on the other side of the dam I would find 900 square miles of a newly-created reservoir. The reservoir was sitting on top of what used to be 900 square miles of virgin rain forest, territory of the southern bearded saki. Oren thought I might be able to find some of the remaining monkeys in forests around around the edge of the reservoir, and he arranged an introduction with some people associated with the company, Electronorte, responsible for the dam.

Within a week I had reached the village of Tucuruí, met with representatives from Electronote, and was racing in a speedboat across the bright surface of the reservoir, accompanied by an English-speaking biologist, Marion Meyer. The boat took us out to an environmental monitoring station at the edge of the reservoir, where Meyer introduced me to a former hunter of bearded sakis named Pedro Pimentel. And it was in the company of biologist Meyer and former hunter Pimentel that, after a long morning's wander through the forest's meandering maze, I heard some high-pitched whistles and squeaks and saw a series of distinctive perturbations in the leaves above. We spent the next couple of days watching and sometimes following a large group of dark, thick-tailed monkeys approximately the size of domestic cats, with human-like grasping hands, and humanoid faces, with strange upraised knobs of fur on their foreheads and peculiar Brillo-pad beards of fur at their chins, who ate leaves and nuts and leapt from one quivering green mattress to another.

So I was able to check off the third primate on my list, a beautiful domestic-cat-sized creature on the edge of disappearing forever. The Brazilians call this monkey Cuxiu.

From there, I flew across an ocean and dropped down onto the edge of another continent, where I went through a similar process: looking for a primate needle in the tropical-forest haystack. The story of this one I'll summarize quickly. I landed in the small West African nation of Sierra Leone and persuaded someone from the Peace Corps office in Freetown, the capital city, to give me a two-day ride in the cab of a small, breaking-down truck. And on the evening of the second day, I arrived at the tiny, moon-lit village of Kambama. After some candle-lit discussions with the village chief, I was ferried in a rubber dinghy onto the Moa River, past the resident crocodile, and out to Tiwai Island, which for historical reasons (several decades of hunting prohibitions maintained by the local chiefdoms) was filled with monkeys, including the species I sought.

As ever, my big map—the political map—provided enough guidance for me to get from one part of the human world (a nation, a city, roads and towns and villages) to another part, while my little maps—the distribution maps—enabled me to travel from one primate world to another. Primate worlds: I had begun to think that way. And I had begun to see my distribution maps as showing a series of secret doorways into those hidden worlds. Every trip makes the traveler look at maps a little differently, and I was no exception. Now, when I see a big map entitled "South America," I say quietly to myself, Yes, that's South America, with all the fingerprints of the human political and demographic presence—and where are the animals? And when I see a big map that identifies itself grandly as, "The World," I think to myself, This is really the human political world. But over there is where the Orangutans live. There is the land of the Mountain Gorillas. And here is the besieged little world of the Golden Lion Tamarins.


So far I have been using the concept of moral organ as an analogy, but let me now suggest that it could be something more than a simple analogy. Ordinarily when we think of organs, we think of a visible and tangible thing: an eye, nose, or ear we can touch, a liver that can be damaged by disease and replaced by a surgeon. But we also recognize that most organs actually include significant parts that can't easily be recognized or touched or even seen. Our organs for sight, for example, consist of not only the accessible outer orb, with its many easily distinguishable parts, but also a less accessible and less visible cable of neurons that quickly expands and merges into an even less accessible, virtually invisible, and very complex electro-chemical processing system that ultimately enables our brains, and our minds, to translate neural information into the coherent and meaningful miracle of sight. Some of the visual organ is visible and tangible. The most complex and arguably most important part is not. The moral organ I am imagining would consist of material that resembles the least accessible, least visible portion of the visual organ. That is to say, the moral organ is essentially neurological in nature.

We tend to believe in the uniqueness of our own human organs just as much as we believe in the uniqueness of our species, but the vast majority of such organs appear in similar form among many other species. Eyes? This organ first appeared in rudimentary form during the Cambrian epoch around 550 million years ago and may have represented such an advantage, according to the thinking of zoologist Andrew Parker, that it caused an evolutionary explosion during which the zoological kingdom expanded in diversity from three major groups, or phyla, to thirty-eight. Noses? What mammals don't have them? Ears? Livers? An evolutionary understanding enables us to appreciate the trans-specific history of organs. Most of them emerged a long time ago, and they have proved to be so useful that they have been retained by a large genetic tree that has over deep time branched and spread tremendously. This truth gives us the best answer to the old chicken-and-egg riddle. Which came first: chicken or egg? We know from many well-preserved fossils that dinosaurs laid eggs and hatched out of them far earlier than 65 million years ago, the date marking the end of the big dinosaurs. We also know that chickens appeared only about 10,000 years ago, when people living in what is today Vietnam domesticated a hybrid of two wild birds, the red and grey junglefowl. So eggs came first, because they're trans-specific.

The moral organ I am imagining may reside primarily in the limbic system of the brain, that large association of neurons located within the deeper layers of the cerebral cortex, although clearly it interacts with many areas of the brain and in any case need not have a specific form or limited location at all. Neuropsychologist Paul MacLean memorably promoted the idea of a limbic system in his book The Triune Brain in Evolution (1990). MacLean argued not merely that the neurocircuitry of the limbic system had been established through evolutionary processes, but also that the fundamental structure of this system evolved long before the evolution of the distinctively human neocortex. Because of its ancient evolutionary roots, he declared, a similar limbic system will be found in the brains of all other mammals. The limbic system generates the affective part of our experience (feelings of sadness, joy, love, hate, anger, excitement, and so on) and it gives emotional significance to information flowing into the brain from the senses (sight, hearing, smell, taste, and touch). Affects—what we more commonly call emotions or feelings—are the internal value-coded experiences that enable us to identify the reproductive and survival value of the things we might wish for or hope to avoid, and of the actions we might take or refrain from taking.

It would be easiest if one could with complete assurance simply name all the moral emotions, and then identify the biochemistry and neurocircuitry identified with each. Certainly we can name some of them, at least for human morality. They would include empathy, guilt, shame, pride, righteousness, a sense of justice, an urge to fairness, an inclination for revenge, and so on. But that list is apparently incomplete and surely simplistic, just as our knowledge of the biochemistry and neurocircuitry of the emotional brain is in its infancy. Moreover, the moral emotions are all situational. That is, they're triggered by very particular situations. And they're also divergent according to our relationship to the moral act in question. One set of emotions becomes appropriate when we're the actors. We might feel guilt or shame at some wrong thing we've done, or pride and righteousness if we've done something right. But when we're watching someone else behave in moral ways, we might feel an entirely different set of emotions. If the other person has done something we consider unfair, for example, we might experience a desire for justice or an urge to fairness. So the emotions governing or promoting moral behavior, the emotions that make up what I am calling the moral organ, are complicated indeed.

Of course, there is the additional issue of whether any of the moral emotions are trans-specific. It has been a common, traditional belief that emotions in general (whether moral or otherwise) are not trans-specific—that, in other words, only people have emotions of any sort, whereas animals don't. But of course animals have emotions. All the best experts on elephants, including the real pioneers in field research on elephants—Iain Douglas-Hamilton, Cynthia Moss, and Joyce Poole—have described many instances of emotional behavior among elephants, and all three have experienced situations that convinced them that elephants feel, for instance, the particular emotion of grief. The best experts on other animals will likewise readily describe emotions they believe they have seen expressed. It is true that emotions are hard to measure, and so at the moment our strongest evidence for animal emotions may be the observations and opinions of field biologists. Any properly skeptical scientist, especially one who has not spent time with animals in the field, may object: We don't really know. I respect the skepticism. I will also note, however, that the skeptical scientist locks up his or her lab at night, goes home to the beloved pooch, and starts talking baby talk. Our favorite dogs and cats have emotions close enough to our own to make us respond with abandon and utter confidence in the authenticity of the experience; and if they have emotional problems, the veternian is liable to give them the same psychoactive drug—Prozac, for example—she takes herself.

—Dale Peterson

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The Moral Lives of Animals by Dale Peterson
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Chimps vs. Humans: How Similar Are We? »

From The Dr. Decker Weiss Show. Original Air Date December 16, 2013. It is a scientifically accepted fact that humans evolved from a common ancestor with chimpanzees, but our similarities and differences are not what many people think. Animal science expert Dale Peterson, PhD, explores the genetic link between the two species and explains the similarities and differences.