By Maria M. Lameiras and Carol Clark
Elise Gilchrist/Think Elephants International, Inc.
Hug It Out
When someone you care about is upset, it’s natural to reach out—to offer a reassuring touch or a soothing word.
Turns out, it’s natural for elephants too.
Asian elephants console others who are in distress using physical touches and vocalizations, according to a recent study led by Joshua Plotnik 10PhD. The findings are the first empirical evidence of consolation in elephants, says Plotnik, who began the research as a graduate student in psychology at Emory. “For centuries, people have observed that elephants seem to be highly intelligent and empathic animals, but as scientists we need to actually test it,” he says.
Consolation behavior is rare in the animal kingdom, with scientific evidence previously provided only for great apes, canines, and certain corvids (a family of birds that includes crows).
“With their strong social bonds, it’s not surprising that elephants show concern for others,” says study coauthor Frans de Waal, professor of psychology and director of Living Links at Emory’s Yerkes National Primate Research Center. “This study demonstrates that elephants get distressed when they see others in distress, reaching out to calm them down, not unlike the way chimpanzees or humans embrace someone who is upset.”
Plotnik is a lecturer in conservation biology at Mahidol University in Thailand and CEO of Think Elephants International, a nonprofit focused on education and conservation. His main research interest is convergent cognitive evolution: The independent evolution of similar features of intelligence in species of different lineages.
While Plotnik was at Emory, he and de Waal provided evidence that elephants can both recognize themselves in a mirror—a test of self-awareness passed only by some apes, dolphins, and magpies—and problem solve cooperatively.
“Humans are unique in many ways, but not in as many as we once thought,” Plotnik says.
The latest study, which was published in the journal PeerJ, focused on a group of twenty-six captive Asian elephants spread over about thirty acres at an elephant camp in northern Thailand. For nearly a year, the researchers observed and recorded instances when an elephant displayed a stress reaction and the responses from other nearby elephants.
The initial stress responses came from either unobservable, or obvious, stimuli: A dog walking past, a snake or other potentially dangerous animal rustling the grass, or the presence of another, unfriendly elephant.
The study found that nearby elephants affiliated significantly more with a distressed individual through directed, physical contact following a stress event than during control periods.
As a typical example, a nearby elephant would go to the side of the distressed animal and use its trunk to gently touch its face, or put its trunk in the other animal’s mouth. The gesture of putting their trunks in each other’s mouths is almost like an elephant handshake or hug, Plotnik says. “It’s a very vulnerable position to put yourself in, because you could get bitten. It may be sending a signal of, ‘I’m here to help you.’ ”
The responding elephants also showed a tendency to vocalize. “The vocalization I heard most often following a distress event was a high, chirping sound,” Plotnik says. “I’ve never heard that vocalization when elephants are alone. It may be a signal like, ‘Shshhh, it’s okay,’ the sort of sounds a human adult might make to reassure a baby.”
In addition, elephants frequently responded to the distress signals of other elephants by adopting a similar body or emotional state, a phenomenon known as emotional contagion, which may be related to empathy. Groups of nearby elephants also were more likely to bunch together or make physical contact with each other.
“One hypothesis for why we don’t see consolation as often is that more complex cognition may underlie it,” Plotnik says. “Rather than just functioning as a way to maintain or repair relationships in a social group, consolation may also require empathy—the ability to put yourself emotionally into someone else’s shoes.”
As a child growing up in Northern California, Rae Wynn-Grant 06C was enthralled by the nature shows she watched on public television, mesmerized by the wild animals and exotic settings.
“The host was almost always an older, white, usually British man. I didn’t even know any of those people. I was an eight-year-old black girl, so I thought it must not be for me,” Wynn-Grant says.
Now a PhD candidate in ecology at Columbia University, Wynn-Grant is completing her dissertation research on the influence of human activity on carnivore behavioral patterns.
Courtesy Rae Wynn-Grant
As part of her research, she has tracked lions, been chased by an angry bull elephant, and dug hibernating female black bears out of their dens to count, weigh, measure, and tag their newborn cubs.
“The fact that I get to go out there and be up close and personal with these animals, doing my best to create important science, it feels like a dream,” she says.
Her dissertation focuses on a population of black bears in the Lake Tahoe Basin of western Nevada. The bears, which are not native to the area, have migrated from Northern California, and Wynn-Grant has been tracking their interaction with humans, their migration patterns, and their survival rates.
The journey from spellbound nature fangirl to intrepid conservation biologist started for her as an undergraduate at Emory.
Contemplating a premed major, Wynn-Grant went to a Department of Biology career fair where different majors offered information on their areas of study. She stopped at the environmental studies booth because she was more interested in whole organisms, not just systems and cells.
“They told me I would be perfect for environmental biology, and they were right,” she says. “It was great from the very beginning. I knew as a freshman that I was in the right spot.”
She took a broad range of classes, from social science to pure ecology, but got hooked on conservation biology.
“I’d never even heard of it or considered it, but I’d always loved nature shows—it was almost an obsession—and this was the study of the science necessary to preserve endangered species and endangered landscapes,” Wynn-Grant says. “Animals were already my thing, and I was learning the complexities of keeping these endangered species on the planet.”
A pivotal experience came in her junior year when Wynn-Grant traveled to Southern Kenya on a study abroad program in wildlife management.
“The environmental science background prepped me very well for the program in understanding the science necessary, but could have better prepared me for living with large African mammals,” Wynn-Grant says with a laugh.
For a suburban kid whose family “didn’t even go camping,” living in thatched huts near traditional tribal villages was challenging, but thrilling.
“We were studying zebras and whether farmers who had been diverting water sources to their farms were changing the zebras’ distribution patterns by changing the landscapes the zebras used,” Wynn-Grant says. “We had some dangerous run-ins with elephants and poisonous snakes—amazing things you see in nature shows. I was this nineteen-year-old college student and at that point I could not believe I was living this life. I decided right then that I wanted to do it for the rest of my life.”
After graduating from Emory, Wynn-Grant worked as a research assistant for the World Wildlife Fund (WWF) in Washington, D.C., before enrolling in the School of Forestry and Environmental Studies at Yale University. There she focused her research on human-wildlife conflict, traveling back to East Africa to study human-lion conflict in farming communities in central Tanzania.
“These pastoralist people have livestock that indicate a fair amount of wealth in their society; it is their whole livelihood. When lions, leopards, hyenas, and other large carnivores take their cows or goats, it is a really big problem and often the pastoralists will kill the carnivores,” she says.
To determine why some carnivores chose livestock over their normal prey, Wynn-Grant and a research group from an African wildlife foundation tracked lions to examine habitat selection and how it coincided with the human communities. “I try to understand the conflict from the animal side. By understanding the animals’ habitat selection, we can help humans choose areas to settle and better avoid conflict,” she says.
Courtesy Rae Wynn-Grant
Immediately after earning her master’s degree from Yale, she enrolled at Columbia University, seeking to continue her African research. However, an excess of native researchers studying the issue left little room in the field for Wynn-Grant.
Advisers at Columbia encouraged her to apply some of the research questions and interests she already had from her previous research to a different species in an ecosystem she could study for a long time—North America. Wynn-Grant connected with the Nevada Department of Wildlife and began research on a population of about four hundred bears that were causing problems in the growing recreation areas around Lake Tahoe on the state’s western edge.
Controversy has brewed between resident bear conservation groups over complaints from property owners about bears coming into human-populated areas to forage. In a number of cases, local authorities have trapped and killed bears that have been deemed nuisance animals.
“There is some mitigation going on, but as researchers we are interested in figuring out the ecological drivers of the conflict. How can we figure it out theoretically and eventually help with urban planning that allows human growth and development, but still allows the black bears to continue expanding their habitats?,” Wynn-Grant says.
Before beginning the project in 2011, Wynn-Grant says she’d never even seen a black bear. Now, every spring, she and her team use GPS technology to find the dens of female black bears—who give birth while hibernating—so they can keep track of the growing bear population in the area.
“In the summer, when the babies are several months old, we look for the mother again to see how many cubs are with her. This tells us if survival rates are favorable in that area,” she says. “If we know survival rates are not optimal in the area, that tells us a lot about how human presence is affecting the bears.”
Once in danger of extinction due to hunting in the late 1800s and early 1900s, black bear populations have rebounded and are flourishing in many parts of the country. This is good for the bears in general, but Wynn-Grant says growing populations are driving the bears to move and colonize new areas. By viewing the problem from the animals’ perspective, Wynn-Grant hopes to give urban planners, policy makers, and developers the tools they need to create communities that can promote harmony among the species.
“This really is a conservation success story, but my challenge, and what I hope to do with my work, is to provide suggestions for coexistence,” she says. “People will continue to develop these beautiful mountain areas and keep making highways and ski resorts and campgrounds. If we can understand how bears use their habitat and the landscape in relation to people, perhaps we can provide recommendations for developments that are sustainable in the natural environment.”
Once she earns a PhD, Wynn-Grant hopes to pursue any one of three dreams—working for a large wildlife conservation organization like WWF, teaching conservation biology to new generations of potential scientists, or hosting her own nature show.
“I’d like to have some sort of media presence that exposes people to nature and wildlife, to scientific inquiry and adventure. I want to be a new face for what this type of science can be. I hope to be an example for young people and encourage them not to feel like ‘If you can’t see it, you can’t become it.’ I disagree. I didn’t see anyone who looked like me, and here I am,” she says.
For now, she’s happy to pull on her hiking boots and hit the woods, doing what she’s always dreamed of doing.
Assistant Professor of Pediatrics Shannon Gourley’s lab at Yerkes is developing mouse models of adolescent-emergent depression, based on research that shows depression in adolescent girls is closely associated with social factors such as bullying and isolation.
“Female mice live in social groups throughout their lives,” Gourley says. “In this research, we isolate the mice during their adolescence. They are kept in an enriched environment with plenty of food and toys, but they are alone. It is unusual for a female mouse to live alone, and this produces a depressive-like state.”
How do you tell when a mouse is depressed?
“When you are talking about mood regulation, it is important to understand what mice like and what they will work for. All mice love sugar, so they will work very hard to get sucrose. So we ask them, under passive circumstances, if they want to drink a delicious ‘mouse milkshake.’ A normal mouse will drink a significant proportion of their body weight,” she says. “By contrast, anhedonic behavior is defined as no longer enjoying things you normally enjoy. Our studies have shown that social isolation reduces sucrose intake. That is, causes anhedonic behavior.”
Further testing using Skinner boxes—testing chambers in which mice are trained that they will receive a “mouse cookie” for pushing a button—measures motivation, another key factor in depression.
“Under easy conditions—when one button-press results in one cookie—both normal mice and depressive-like mice will perform the same way. Once they have mastered that task, we ask how hard they will work for a reward. A normal mouse will perform fifty to sixty nose pokes for just one mouse cookie, while depressive-like mice show, very consistently, a one-third drop in how willing they are to respond,” Gourley explains. “This models lack of motivation in depression.”
Adolescent depression and mood disorders are of particular interest to Gourley because of the challenges in treating the disease and realizing long-term relief from depression. Her lab’s work is supported by the National Institutes of Health and the Brain and Behavior Research Foundation, established by the Deschner family.
“Individuals who develop depression during adolescence are more likely to relapse along the course of their lifetimes,” Gourley says. Treatment strategies also are very limited because most current antidepressants are not recommended for adolescents.
“My lab’s research is aimed at developing interventions for adolescents using novel antidepressant compounds that will carry therapeutic effects into adulthood,” Gourley says. Building on the known biological mechanisms of how cells are developing and how certain known drugs work, Gourley is testing an established drug currently used for other applications for use in treating adolescent depression. Fasudil, a drug that widens blood vessels, is used in Japan to treat a stroke precursor called cerebral vasospasm and is in clinical trials in the United States for treatment of ALS (amyotrophic lateral sclerosis), also known as Lou Gehrig’s disease.
“We are using this drug because it appears to optimize, or facilitate, the development of the prefrontal cortex. Prolonged stress during adolescence derails this cortical development and is a factor in depression,” she says.
Because a mouse’s adolescence only lasts about thirty days, it is easy to determine the long-term outcomes.
“We have evidence that this drug is optimizing cortical development and reversing the depressive-like state in mice. We stop treatment with the drug at day sixty, or even earlier, and our findings show that it is allowing them to grow up into middle-aged, quite typical, normal mice. This has important implications for successfully treating our youngest, most vulnerable depressed populations,” Gourley says.
Have I Seen You Somewhere?
Whether you are terrible at remembering faces or you never forget one, it may all come down to your DNA, says Larry Young, director of Emory’s Center for Translational Social Neuroscience at Yerkes.
In previous research, Young noticed that mice with a mutated oxytocin receptor failed to recognize mice they previously encountered. He made the leap in logic from mouse to man by correlating rodents’ use of odors for social recognition to humans’ use of visual facial cues.
More recently, researchers found that the oxytocin receptor also plays a special role in the ability to remember faces. Young says this is the first study to demonstrate that variation in the oxytocin receptor gene influences face recognition skills.
While oxytocin plays an important role in promoting humans’ ability to recognize one another, about one-third of the human population possesses the genetic variant that negatively impacts that ability.
Young and the research team studied 198 families with a range of variability in facial recognition skills. By examining the influence of subtle differences in oxytocin receptor gene structure on face memory competence in family members, the researchers discovered that a single change in the DNA of the oxytocin receptor had a big impact.
Scent of Danger
In a genetic twist on helicopter parenting, Yerkes researchers have found that when a mouse learns to become afraid of a certain odor, his or her pups will be more sensitive to that odor, even though the pups never have encountered it.
“Knowing how the experiences of parents influence their descendants helps us to understand psychiatric disorders that may have a transgenerational basis and possibly to design therapeutic strategies,” says senior author Kerry Ressler, professor of psychiatry and behavioral sciences in the School of Medicine.
Ressler and postdoctoral fellow Brian Dias trained mice to become afraid of an odor by pairing exposure to the odor with a mild electric shock. He then measured how much the animal startled in response to a loud noise by itself and in conjunction with the odor.
Surprisingly, they found that the naive adult offspring of the sensitized mice also startled more in response to the particular odor that one parent had learned to fear. In addition, they were more able to detect small amounts of that particular odor.
Researchers are continuing the study, hoping to answer questions about whether the effects of the sensitization are reversible.
Singing for Survival
For white-throated sparrows, listening to another sparrow’s song may rouse some of the same emotions humans feel when listening to music.
These findings are part of the first study to compare the brain responses of birds to birdsong with the brain responses of humans listening to music. Proposed by a student and performed in the lab of Associate Professor of Psychology Donna Maney, the study sought to settle the longstanding debate over whether birdsong is music.
“Birdsong is a signal,” says Maney, lead investigator of the study. “And the definition of a signal is that it elicits a response in the receiver. Previous studies hadn’t approached the question from that angle, and it’s an important one.”
For females in the breeding state, every region of the avian counterpart of the reward pathway in the brain that has been reported to respond to music in humans showed a response to the male song. Females in the nonbreeding state, however, did not show a heightened response.
“The neural response to birdsong appears to depend on social context, which can be the case with humans as well,” says Sarah Earp 12C, who was lead author of the paper as an undergraduate at Emory. “Both birdsong and music elicit responses not only in brain regions associated directly with reward, but also in interconnected regions that are thought to regulate emotion. That suggests that they both may activate evolutionarily ancient mechanisms that are necessary for reproduction and survival.”
Loving and Learning
Larry Young has spent the past two decades studying two different species of voles to determine why one is generally a loyal lover, while the other is a wandering lothario.
The answer comes down to a key difference in the receptors in the brains of monogamous prairie voles and promiscuous meadow voles that respond to the bonding hormones oxytocin and vasopressin. The hormones are present in both species’ brains, but only prairie voles have active receptors in brain regions that reinforce the emotional rewards of social interactions and caring for their young.
By expressing these receptors in the reward regions of animals that do not normally have them, Young and his colleagues have been able create social bonds in the normally detached meadow voles. Humans also have vasopressin receptor genes that predict some aspects of human behavior, including romantic relationship quality.
Boosting the human oxytocin system with medications that stimulate natural oxytocin release during behavioral therapy could benefit people with autism spectrum disorders by making social interactions more intuitive.
“This could have tremendous potential in helping people with autism,” says Young, who was recently elected to the American Academy of Arts and Sciences.
Ben and Jerry’s, Anyone?
Anyone who’s ever turned to a pint of ice cream to deal with stress or heartbreak now has science to back them up.
Mark Wilson, research professor in the Division of Developmental and Cognitive Neuroscience at Yerkes National Primate Research Center, and Zach Johnson, assistant research professor at Yerkes and in the Department of Genetics at Emory School of Medicine, are studying the adverse influence of stress and social factors on appetite and food preference on health. By understanding how stress leads to comfort food ingestion, they hope to identify the physical triggers that drive people to overeat.
In Wilson’s preliminary study of fifty socially housed female rhesus macaques at Yerkes’ field station, subordinate monkeys within the groups ate fewer calories than dominant monkeys when given their normal low-fat, high-fiber diet. However, when the animals were given a choice between their normal diet and one that was high in fat and sugar, the low-ranking monkeys quadrupled their calorie intake, while dominant monkeys maintained normal calorie consumption—even though they too preferred the high-calorie food. When switched back to the low-fat diet, subordinate animals continued to eat greater quantities of food, underscoring the notion that dieting just by eating healthier food is difficult.
“While the relation of stress and comfort food ingestion is appreciated by us all, we now have the opportunity to begin to understand the biology of how stress leads to overeating,” says Wilson.
Johnson is examining how these changes in diet influence peripheral gene expression, particularly genes related to inflammation.
“We are seeking to identify changes we hope will lead to identifying the genetic modifiers that predispose individuals to stress-induced overeating and obesity,” he says. “If we can understand how stress and a high-calorie diet interact to change the biology of a rhesus monkey, we are much closer to developing methods for the treatment of obesity in humans.”
With each passing year of research, Frans de Waal, C. H. Candler Professor of Psychology, narrows the gap between humans and the animal world.
Decades ago, de Waal was one of the first to provide evidence of reconciliation in nonhuman primates, showing how chimpanzees make up with one another after a fight. De Waal’s research also demonstrated consolation behavior: After two chimpanzees fight, a third might come over and console the distressed loser of the battle with an embrace.
In a 2013 study on fairness, de Waal and his fellow researchers at Yerkes used the ultimatum game, in which two participants must agree on a distribution for both to receive rewards, to see how chimpanzees would respond compared to human children.
One individual chose between two tokens—one type of token that offered equal rewards to both players and another type of token that rewarded only the chooser. The chooser then needed to hand the token to the partner, who needed to exchange it with the experimenter for the reward. Both apes and children responded like humans typically do. If their partner’s cooperation was required, they split the rewards equally. However, with passive partners—who had no part in receiving the reward—both children and chimps preferred the selfish option.
“A growing body of evidence shows that we have grossly underestimated both the scope and the scale of animal intelligence,” de Waal wrote in an essay for the Wall Street Journal when his book The Bonobo and the Atheist: In Search of Humanism among the Primates was published in March 2013. “The one historical constant in my field is that each time a claim of human uniqueness bites the dust, other claims quickly take its place. Meanwhile, science keeps chipping away at the wall that separates us from the other animals. We have moved from viewing animals as instinct-driven stimulus-response machines to seeing them as sophisticated decision makers.”
The Next Big Thing
Associate Professor of Medicine Tim Read was looking for a big project when he got in touch with marine biologist Al Dove, director of research and conservation at Georgia Aquarium.
Having already mapped the genomes of several species of bacteria, Read wanted to put his lab to the test with a larger challenge.
He got it in the aquarium’s population of whale sharks. The filter-feeding behemoths can grow to upwards of forty feet long, weighing in at more than forty-seven thousand pounds. The ancient creature originated approximately sixty million years ago and is one of only three known filter-feeding shark species.
“It’s like mapping a new continent. You have an expectation of what you will find when you get there, but there is a possibility of finding something new while you are mapping the topography,” Read says. “When you have that, you can start examining it comparative to other species and ask questions about what is unique in the biochemistry of the whale shark.”
All living organisms have the same four chemicals—adenine, cytosine, thiamine, and guanine—in different combinations on each DNA molecule. The human body, for example, has three billion genetic sequences. Read estimates that the whale shark may have six billion.
“We are now completing the final set of data production, and then we will have enough to analyze and publish our findings,” he says. “When we have the whole sequence, we then have a tool to use to ask questions about the whale shark population and questions comparative to other species. Whale sharks have an ancient immune system. With a completed picture of how its genome is constructed, there is a possibility to discover new parts of its immune system and new anti-infective molecules.”
Read also hopes he and other scientists will be able to use the information to attract new scholars to the field of genomics.
“This would be a great way to teach undergraduates about genomics, having them ask simple questions that they can use these data to answer,” Read says.
Take One and Pass It On
Because sharing 96 percent of our DNA isn’t enough evidence that we are alike, Yerkes National Primate Research Center researchers Matthew Campbell and Frans de Waal have completed a study that shows chimpanzees exhibit flexibility in their empathy, just as humans do.
The researchers found chimpanzees showed contagious yawning to familiar chimpanzees, familiar humans, and unfamiliar humans, but not to unfamiliar chimpanzees or an unfamiliar species.
While it’s long been known that human empathy can extend to family, friends, strangers, and even other species, it has not been known until now whether other species are similarly broad in their empathic responses.
To answer this question, Campbell and de Waal used contagious yawning as a measure of involuntary empathy. Humans will yawn in response to people they don’t know, showing flexibility in empathy, but chimps won’t yawn in response to unknown chimps or unknown species.
“Copying the facial expressions of others helps us to adopt and understand their current state,” says Campbell. “We can use this information to try to influence this flexible response in order to increase empathy toward unfamiliar chimpanzees, and we hope we will be able to apply such knowledge to humans as well.”
Bugs on Drugs?
Insects outnumber every other living thing on the planet by a sizeable margin, with at least six million species—the vast majority of which have yet to be identified. Their evolution and behavior hold countless scientific mysteries. But small discoveries can yield big, and often unexpected, rewards.
Some insects are experts at extracting what they need from the ecology around them. For instance, it appears that monarch butterflies may be able to cure themselves and their offspring of disease by using medicinal plants, according to research by Jaap de Roode, assistant professor of biology.
Few studies have been done on self-medication by animals, but some scientists have theorized that the practice may be more widespread than we realize.
Kenneth Dwain Harrelson/Wikipedia
Monarch caterpillars feed on any of dozens of species of milkweed plants, including some species that contain high levels of cardenolides. These chemicals do not harm the caterpillars, but make them toxic to predators even after they emerge as adults from their chrysalises. Experiments in de Roode’s lab also have shown that a female infected with the harmful parasite Ophryocystis elektroscirrha prefers to lay her eggs on a toxic species of milkweed, rather than a non-toxic species. Uninfected female monarchs, however, showed no preference.
Another Emory study found that fruit flies infected with a blood-borne parasite consume alcohol to self-medicate, a behavior that greatly increases their survival rate.
Researchers in the lab of Assistant Professor of Biology Todd Shlenke use Drosophila melanogaster, the common fruit fly that swirls around browning bananas, to study how immune systems adapt to pathogens.
The fly larvae eat the rot, or fungi and bacteria, that grows on overripe, fermenting fruit to protect against infectious disease. “Our data raise an important question: Could other organisms, perhaps even humans, control blood-borne parasites through high doses of alcohol?” Schlenke says.
Pea aphids, expert survivors of the insect world, are major agricultural pests and also important biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and genetic plasticity. These resilient insects thrive despite a host of enemies, including parasitic wasps, ladybugs, fungal pathogens, and frustrated farmers and gardeners the world over. They also are potential resources for questions related to human health.
“Some people feel sick when they take antibiotics because the drug kills off all the beneficial bacteria. If we can study the process of how to keep beneficial bacteria while clearing out harmful bacteria across several organisms, including aphids, we might be able to understand it better,” says Nicole Gerardo, assistant professor of biology.