Natural Passions

Mounting evidence suggests that animals feel a wide array of humanlike emotions, from happiness, sadness and anger to perhaps even love and embarrassment

• Laura Tangley
• Jul 01, 2001

AS A BIOLOGIST working for the Amboseli Elephant Research Project in Kenya, Joyce Poole has seen plenty of fascinating behaviors since she began studying these behemoths more than a quarter century ago. Among her favorites are what elephants do at the "greeting ceremonies" she observes when members of the same family or group meet after a separation. According to Poole, up to 50 of the animals rush together loudly, flap their ears wildly and spin in circles, all the while emitting a chorus of rumbles, roars, screams and trumpets. She's convinced "that greeting elephants feel a deep sense of joy at being reunited with friends and that their rumbles and roars express something like: Wow! It's simply fantastic to be with you again.'"

Primatologist Jane Goodall also has seen her share of joyful behavior among chimpanzees living in Tanzania's Gombe National Park. But she was perhaps most touched by the sorrow she witnessed once after a 50-year-old matriarch of the troop she was studying died. Throughout the day following the old female's death, her eight-year-old son sat vigil by his mother's lifeless body, occasionally taking her hand and whimpering. Over the next few weeks, he grew increasingly listless, refused food and finally withdrew from the troop. Three and a half weeks after his mother's death, the formerly healthy young chimp also was dead. "He died of grief," concludes Goodall.

Field biologists such as Poole and Goodall, who've each spent decades studying the behavior of animals in their natural habitats, do not doubt that elephants, chimpanzees and other creatures feel intense, humanlike emotions - from happiness, sadness and anger to perhaps even love and embarrassment. But among many other scientists, the idea that animals feel emotion has long been, and remains, controversial. Their skepticism is driven in part by professional aversion to anthropomorphism, the very nonscientific tendency to attribute human qualities to nonhuman animals. Some researchers also point out that it is impossible to prove animals have emotions through standard scientific methods - repeatable observations that can be manipulated in experiments - leading them to conclude that such feelings therefore cannot exist.

These days, however, amid mounting evidence to the contrary, "the tide is turning radically and rapidly," says Marc Bekoff, a biologist at the University of Colorado-Boulder. Research by Bekoff and others - in fields ranging from ethology to neurobiology - is beginning to provide scientific support for the notion that animals feel a wide range of emotions. These findings, they believe, have profound implications for how humans and other species will interact in the future.

Even scientists who are most opposed to the idea of animal passion acknowledge that many creatures experience "primary emotions" - feelings such as aggression and fear that are instinctive and require no conscious thought. Essential to escaping predators and other dangers, fear, in particular - along with predictable freeze, flight or fight responses - seems to be hardwired. A laboratory rat that has never encountered a cat, for example, will still freeze if it is exposed to the smell of this predator.


But beyond such instinctive behavior, "secondary emotions" such as happiness and sadness have been flatly denied by most scientists for the past several hundred years, with one notable exception: In The Expression of the Emotions in Man and Animals, published in 1872, Charles Darwin argued that there is continuity between the emotional lives of humans and other animals, attributing differences to degree rather than kind. "The lower animals, like man, manifestly feel pleasure and pain, happiness and misery," he wrote. But in contrast to his theory of evolution by natural selection, Darwin's ideas about animal emotions did not catch on among mainstream biologists.

There's no question that emotions are difficult to study. "I can't prove that another human being is feeling happy or sad," says Bekoff, "but I can deduce how they're feeling through body language and facial expression." As a biologist who has conducted field studies of coyotes, foxes and other canids for the past 30 years, Bekoff also believes he can tell what these animals are feeling by looking for clues such as changes in posture, facial expression, pupil size and vocalization. Subsequent behavior - a fight following the appearance of aggression, for instance - can confirm these hunches.

Growing acceptability of such field observations, or anecdotes, has been key to making today's case for animal emotions. Long maligned among most researchers, the anecdote "must be revalued and reinstated into science under its old and honored descriptor: the case study," writes Harvard University's Stephen Jay Gould in the forward to a recent book, The Smile of a Dolphin. Edited by Bekoff, the book features essays from more than 50 scientists who have spent their careers watching animals. As Bekoff points out to critics of this case-study approach, "the plural of anecdote is data."

Take pleasure. Anyone who's ever held a purring cat, or been knocked down by a leaping, barking, tail-wagging dog, knows that animals often appear to be happy. Beastly joy seems particularly apparent when animals play with one another. According to Bekoff, virtually all young mammals as well as some birds play, as do the adults of many species, including, of course, humans.

Dolphins, for example, are often seen chasing each other through the water like frolicsome puppies or riding the wakes of boats like surfers. According to Goodall, young chimpanzees "chase, somersault and pirouette around one another with the abandon of children." In Colorado, Bekoff once saw an elk race back and forth across a patch of snow (even though plenty of bare ground was available), leaping and twisting its body on each pass. Recent research suggests that play helps young animals develop skills they need in adulthood. But they're also having fun, says Bekoff. "Animals at play are symbols of the unfettered joy of life."


So, too, can be creatures that seem to be in love. The most widespread displays of affection are between parents and offspring. But some researchers also have reported what looks like romantic love. Bernd Würsig, a Texas A&M University biologist, was studying right whales off the coast of Argentina when he saw a female choose just one of many suitors pursuing her (in contrast to "normal" behavior marked by promiscuity). After mating, the two whales lingered side-by-side, stroking each other with their flippers, then rolled together in what looked like an embrace. Finally the cetaceans departed, yet remained touching as they swam away slowly, diving and surfacing in unison.

As a scientist, Würsig believes his observation should be considered no more than "an alternative mating strategy." But he still entertains the notion that the animals acted as they did "because they were the 'right' right whales for each other."

Love's flipside, heartbreak, also is reported by researchers, particularly when animals lose a mate, parent, offspring or close companion. A female sea lion, for instance, wails forlornly if she sees a killer whale eating her pup. Geese, which mate for life, hang down their heads and droop their bodies dejectedly following the death of a partner. And like the chimp Goodall observed in Gombe, creatures ranging from great apes and monkeys to bears, moose and antelope stand vigil beside the bodies of deceased family members, sometimes succumbing to withdrawal, sickness and death themselves.

Elephants, well-known to biologists like Poole for their rambunctious displays of pleasure, take grief to an extreme as well. She and other field researchers have recorded many instances of the animals standing quietly beside the body of a dead elephant, occasionally reaching out and touching it with their trunks. Elephants also carry the tusks and bones of their departed kin great distances and may even try to cover them with dirt or leaves. After nearly three decades studying the animals, Poole says that elephants' behavior toward the dead "leaves me with little doubt that they experience deep emotions and have some understanding of death."

There is "hard" scientific evidence for animal emotions as well. Neuroscientists who study the biology of emotions, a discipline still in its infancy, have discovered key similarities between the brains of humans and other animals. In all species studied so far, including our own, emotions seem to arise from long-evolved parts of the brain - particularly the amygdala, an almond-shaped structure in the brain's center. Working with rats, they have found that stimulating one part of the amygdala invariably induces a state of intense fear. Rats with damaged amygdalae exhibit neither normal behavioral responses to danger (such as freezing or running) nor the physiological changes associated with fear (such as higher heart rate and blood pressure).

Brain imaging studies show that when humans experience fear, their amygdalae, too, become activated. And like the rats, people who have suffered damage to this part of the brain are unable to be afraid, even when circumstances warrant it. New York University neuroscientist Joseph LeDoux, whose lab conducted many of the rat experiments, concludes that the amygdalae of humans and rats are "basically wired the same way."


Research on brain chemistry also bolsters the case for animal feelings. Stephen Siviy, a behavioral neuroscientist at Gettysburg College in Pennsylvania, has found that when rats play with each other, their brains secrete large amounts of dopamine, a chemical that is associated with pleasure and excitement in humans. In one experiment, he placed pairs of rats in distinctive Plexiglas chambers and allowed them to play. A week later, Siviy realized that he could place one rat by itself in a chamber and, anticipating play, the animal "becomes very active, vocalizing, and pacing back and forth with excitement." But if he gave the same animal a drug that blocks dopamine, all such activity ceased. Jaak Panksepp, a neuroscientist at Bowling Green State University in Ohio, discovered that rats also produce opiates when they play, chemicals that, like dopamine, are involved in the experience of pleasure in people.

Another chemical, the hormone oxytocin, is associated with both sexual activity and maternal bonding in humans. Now it seems that the same hormone governs attachment among some animals. To investigate oxytocin's role in bonding between mates, University of Maryland neuroscientist C. Sue Carter studied a mouselike rodent called the prairie vole, one of the few mammal species known to be monogamous. Carter discovered that female voles, which ordinarily spend a day selecting a mate, will choose one within an hour (often the first male she sees) if she's just received an injection of oxytocin. But females given a drug that blocks the hormone never pick a mate no matter how much time they have. According to Carter, oxytocin triggers behavior in voles that looks much like people who are "falling in love."

Looks can be deceiving, though. Even the most ardent believers in animal passion warn that humans can easily misinterpret what they're seeing. The shape of a dolphin's mouth, for example, leads to the conclusion that the animal is smiling or laughing, even when it is afraid or in distress. Chimpanzees have a facial expression signaling fear that also is misunderstood as smiling. "It's both presumptuous and dangerous to blindly assume that animal emotions are the same as ours," says Bekoff.

Such caveats help fuel the arguments of skeptics. "A whale may behave as if it's in love, but you cannot prove what, if anything, it is feeling," says LeDoux, author of The Emotional Brain. LeDoux believes the question of feelings ultimately boils down to whether or not animals are self-conscious. And though they "may have snapshots of self-awareness," he says, "the movie we call consciousness is not there." University of Wisconsin neuroscientist Richard Davidson agrees that very few species (higher primates and, most recently, dolphins) have demonstrated self-consciousness so far. Yet he suspects that at least some other animals "may have the antecedents of feelings."


Or maybe more. Biologists such as Bekoff say their most convincing argument comes from the theory of evolution itself. Citing remarkable similarities between the brain anatomy and chemistry of humans and other animals, Siviy asks: "How can you believe that feelings suddenly appeared, out of the blue, in human beings?" Goodall adds that neuroscientists who study animals to learn about the human brain, then deny that those animals have emotions, are "illogical."

But if in fact there is continuity between the emotional lives of humans and other animals, where does one draw the line? Even Bekoff says "we're not going to talk about jealous sponges and embarrassed mosquitoes."

Yet happy iguanas are another matter. In experiments with these tropical reptiles, Michel Cabanac, a physiologist at Laval University in Quebec, found that when they're in a comfy, warm spot - which the animals prefer over areas that have food but are cooler - they show physiological changes that are associated with pleasure in mammals. Frogs and fish, on the other hand, do not. Cabanac proposes that emotions evolved somewhere between amphibians and the first reptiles.

In the end, though, what difference does it make if an iguana is happy but a frog is not? Many scientists maintain that resolving the debate over animal emotions is much more than an intellectual exercise. If animals do experience a wide range of humanlike feelings, they say, it has implications for how they are treated by our own species. Bekoff, for one, would like to see a world where people ate no meat or animal products, and circuses, zoos and marine parks were shut down. But he's also realistic, hopeful that the new case for animal emotions will at least spur changes in regulations governing the use of animals everywhere from zoos and biomedical labs to farms, pet stores and animal shelters.

Bekoff and his colleagues also hope that the debate over animal emotions and consciousness will soon shift - from whether nonhuman species have them to how they experience them. Sitting outside his Boulder home one sunny afternoon, Bekoff turned to his big, friendly dog Jethro. "I know that Jethro's consciousness is not the same as mine," he acknowledged. "But there's no question that he has dog consciousness."

Senior Editor Laura Tangley shares a home with some emotional cats and turtles. Photographs by Anup and Manoj Shah.