Rhesus macaque and baby

The life of a monkey is full of ups and downs. Like us, monkeys form strong friendships and bitter rivalries. They fight for each other and take care of one another. And the leader of a monkey troop, when deposed, will even exhibit signs of depression. When we watch their behavior we get the sense that their emotional lives may share something in common with our own.

Friends and Enemies

Monkeys have a complex social system, and they form relationships with each other on an individual basis. When they encounter each other, monkeys will remember back to past interactions. Old rivals can be greeted with rage if they swing into the wrong part of the jungle. As we see in Clever Monkeys, such skirmishes sometimes even end in death.

By the same token, monkeys will remember the help of a friend. Grooming, for example, shows affection and respect. And when it’s time for a fight, a monkey with whom you’ve built a friendship is much more likely to fight at your side — or clean your wounds afterward!

Dealing with Death

Toque macaques huddle together after a member of their troop is killed in Clever Monkeys. Image © BBC

In Clever Monkeys, when the leader of a troop of toque macaques is killed, the others gather in silence around his body. As though they truly feel remorse, even his old rivals now seem to show their deference, tenderly touching their fallen leader.

Everyone is affected by death, but a monkey mother that has lost her infant seems especially hard-hit. In nearly all species of monkey, the mother will carry her child’s lifeless body around with her for days. Do these examples show that monkeys share our emotional response to death? Some researchers suggest that while they may not understand death in the same way we do, monkeys and apes do seem share our tendency to have trouble accepting it.

Stressed Out!

Monkeys suffer from stress, much like we do, and often it seems to relate to social problems. For example, baboon society is extremely competitive. Males who try to move up the social ladder and fail can suffer from high blood pressure and even ulcers. But those at the top don’t necessarily have it any better: high-ranking males who fall from power often exhibit signs of depression.

A Mother’s Love

A mother monkey’s attention and care during her child’s infancy has a significant impact on the young monkey’s emotional development. Infant rhesus and pigtail monkeys react to the absence of their mothers in much the way we would expect a human child to react. At first, they coo for her and search excitedly. However, after a while, they will stop playing with others and take on a slouched posture.

A lack of love from mother and peers during infancy has an even greater effect later in life. In one study, three-year-old rhesus monkeys that were isolated during their first year of life showed much more aggression toward unknown monkeys than did their peers.

From maintaining complex social relationships, to suffering anxiety and depression, there are many trials in the life of a monkey. Perhaps the next thing monkeys should consider evolving is a good therapist.

Photo (top) © Charlotte Scott

Elephants, the largest land animals on the planet, are among the most exuberantly expressive of creatures. Joy, anger, grief, compassion, love; the finest emotions reside within these hulking masses. Through years of research, scientists have found that elephants are capable of complex thought and deep feeling. In fact, the emotional attachment elephants form toward family members may rival our own.

Joy

In the wild, joy is an emotion that elephants have no shame in showing. They express their happiness and joy when they are amongst their loved ones-family and friends. Playing games and greeting friends or family members all elicit displays of joy.

But the one event that stirs a level of elephant happiness beyond compare is the birth of a baby elephant. In Unforgettable Elephants, the birth of Ebony is one such occasion. The excitement of several of the females in Echo’s family can’t be contained as they are heard bellowing and blaring during the birth of the new baby.

Another highly emotional occasion in an elephant’s life is an elephant reunion. This joyful meeting between related, but separated, elephants is one of exuberance and drama. The greeting ceremony marks the incredible welcoming of a formerly absent family member. During the extraordinary event, the elephants about to be united begin calling each other from a quarter a mile away. As they get closer, their pace quickens. Their excitement visibly flows as fluid from their temporal glands streams down the sides of their faces. Eventually, the elephants make a run towards each other, screaming and trumpeting the whole time. When they finally make contact, they form a loud, rumbling mass of flapping ears, clicked tusks and entwined trunks. The two leaning on each other, rubbing each other, spinning around, even defecating, and urinating (for this is what elephants do when they are experiencing sheer delight). With heads held high, the reunited pair fill the air with a symphony of trumpets, rumbles, screams, and roars. Bliss.

Love

There is no greater love in elephant society than the maternal kind. Nobody who observes a mother with her calf could doubt this. It is one of the most touching aspects of elephant social customs. The calf is so small compared to the adult that it walks under its mother, who, incredibly, does not step on it or trip over it. Mother and child remain in constant touch. If a calf strays too far from its mother, she will fetch it. The mother often touches her child with trunk and legs, helping it to its feet with one foot and her trunk. She carries it over obstacles and hauls it out of pits or ravines. She pushes it under her to protect it from predators or hot sun. She bathes it, using her trunk to spray water over it and then to scrub it gently. The mother steers her calf by grasping its tail with her trunk, and the calf follows, holding its mother’s tail. When the calf squeals in distress, its mother and others rush to its protection immediately. It is easy to see why the bond between mother and daughter lasts 50 years or more.

Grief

One of the most moving displays of elephant emotion is the grieving process. Elephants remember and mourn loved ones, even many years after their death. When an elephant walks past a place that a loved one died he or she will stop and take a silent pause that can last several minutes. While standing over the remains, the elephant may touch the bones of the dead elephant (not the bones of any other species), smelling them, turning them over and caressing the bones with their trunk. Researchers don’t quite understand the reason for this behavior. They guess the elephants could be grieving. Or they could they be reliving memories. Or perhaps the elephant is trying to recognize the deceased. Whatever the reason, researchers suspect that the sheer interest in the dead elephant is evidence that elephants have a concept of death. In Unforgettable Elephants, when Erin is wounded, Echo and the family never wander far from her over the course of several days, leaving only to drink. After Erin’s death, her family touched and smelled the bones, as filmmaker Martyn Colbeck says, “as if they were trying to understand what had happened.”

Researchers have described mother elephants who appear to go through a period of despondency after the death of a calf, dragging behind the herd for days. They’ve also witnessed an elephant herd circling a dead companion disconsolately. After some time, and likely when they realized the elephant was dead, the family members broke off branches, tore grass clumps and dropped these on the carcass. Another researcher noted a family of African elephants surrounding a dying matriarch. The family stood around her and tried to get her up with their tusks and put food in her mouth. When the rest of the herd finally moved on, one female and one calf stayed with her, touching her with their feet.

Rage and Stress

Terror, rage and stress, unfortunately, are also commonplace in the elephant repertoire of emotions. Terror afflicts baby African elephants who wake up screaming in the middle of the night after they have witnessed their families murdered and poached — a type of Post Traumatic Stress Disorder.

Some researchers suggest a species-wide trauma is taking place in wild elephant populations. They say that elephants are suffering from a form of chronic stress after sustaining decades of killings and habitat loss. The recent surge in cases of wild elephant rage reported by the media is a sad indicator of the kind of stress that wild elephants are undergoing. Nearly 300 persons are killed every year by wild elephants in India. But the increasing numbers of deaths are closely correlated to the ever-increasing human presence in traditional wild elephant habitats, as well as the the effects of climate change, and loss of territory and resources. The ongoing competition between elephants and humans for available land and resources is leading to ever more unfortunate and often deadly consequences.

Human activity does more than put a stress on elephants to find resources. It can often disrupt the complex and delicate web of familial and societal relations that are so important in elephant society. Calves are carefully protected and guarded by members of the matriarchal elephant family. Any perception of danger triggers a violent reaction from the matriarch and, subsequently, the entire family. The extremes a family will go to protect a vulnerable new calf are reported in the news stories as fits of unprovoked “elephant rage.” Charging a village, storming into huts where harvested crop is stored, plundering fields and, if disturbed, turning violent are some of the instances reported by the media.

Compassion and Altruism

In Unforgettable Elephants, viewers witnessed a desperate mother who just gave birth to a premature calf. The mother and several other females refused to abandon the baby, even in its desperate state. They clustered around the nearly-dead calf while, in a touching display, the mother tried with all of her might to move the calf using her tusk and trunk. Her inability to maneuver the limp baby may have been heartbreaking but her determination and compassion for the newborn was remarkable. Compassion is not reserved for offspring alone in elephant society. Elephants appear to make allowances for other members of their herd. Observers noted that one African herd always traveled slowly because one of its members had never recovered from a broken leg. And in another case, a park warden reported a herd that traveled slowly because one female was carrying around a dead calf. One perplexing report was of an adult elephant making repeated attempt to help a baby rhinoceros stuck in the mud. She continued to try to save the baby rhino despite the fact that its mother charged her each time. Risking her life for the sake of an animal that is not her own, not related to her, or even her own species is remarkably altruistic in nature.

While there is a great deal more to learn about what elephants feel, such accounts are astonishing. They reveal a creature that weeps, revels, rages and grieves. They lead us to believe that the depth of elephant emotional capacity knows no limit. They are striking for they suggest that elephants act on feelings and not solely for survival.

Happiness, sadness, anger, fear, love, hate — emotions play a pivotal role in our lives. But do they loom large in an animal’s world as well? Part Two of NATURE’s Inside the Animal Mind explores that question in fascinating detail.

In large part, researchers have found that emotions are accompanied by biochemical changes in the brain. Fear, for instance, is accompanied by the production of one set of brain chemicals that can make us alert and ready to flee, while pleasure triggers the release of other chemicals that soothe and calm. But some emotions aren’t so biologically clear-cut. Shame, for instance, is a so-called “social emotion,” the product of attaching an emotional meaning to a behavior, such as hitting another person, or lying, that may be appropriate in one social setting but out of bounds in another.

Like humans, baboons harass each other, compete for rank, and undergo stress.

While researchers don’t agree on how big a role such social emotions play in the animal world, there is widespread agreement that many animals share another emotional characteristic with us: stress. Indeed, like humans, many animals can be harried and “stressed out” — with sometimes serious health consequences.

Among the most remarkable studies of stress in animals are those carried out on African baboons by Stanford University research Robert Sapolsky and his colleagues. For three months each year, Sapolsky travels to East Africa’s Serengeti plain to examine how factors like a baboon’s social behavior, personality, and rank within its troop influence the levels of stress hormones produced by the ape. By measuring the hormones found in each individual’s feces, Sapolsky’s team has been able to show that baboon troops are high-stress societies, with higher-ranked individuals maintaining order by intimidating lower-ranked troopmates. Indeed, Sapolsky says, “Baboons and us are surprisingly similar . . . they can devote a large part of each day to making each other absolutely miserable with social stress.”

Sapolsky’s team has also shown that such stress can have real health consequences. Stressed-out mothers, for instance, have more problems producing healthy offspring. And sustained production of stress hormones can also damage the hippocampus, a region of the brain central to learning and memory. So even though baboons may not commute, do their bosses’ dry cleaning, or pay income taxes, they suffer very similarly from the scourge of stress.

Intriguing surprises await viewers Inside the Animal Mind a three-part NATURE miniseries.

We all believe that our pets are both intelligent and sensitive. After all, they understand our commands, read our moods, and know just how to manipulate us to get what they want. In some ways, they anticipate our behavior as accurately as we do theirs.

But are these truly examples of intelligence, or simply the results of trial and error derived from millennia of contact with humans? Can animals actually apply insight to problem-solving and understand abstract concepts? Do they reflect on the past and worry about the future? Are they capable of recognizing their own mortality?

NATURE explores the intriguing subjects of animal intelligence, emotions, and self-awareness, when it takes viewers Inside the Animal Mind.

To order a copy of Inside the Animal Mind, please visit the NATURE Shop.
Online content for Inside the Animal Mind was originally posted January 2000.