tufts universitytufts magazine issue homepage
contact us back issues related links
 
features What Keeps Us Running Peanut Butter and Magic Defiance The Good Mother Gaming the System American Idyll think tankplanet tufts newswire the big day departments

The Good Mother

A GIRAFFE’S MATERNAL INSTINCTS ARE STRONGER THAN zOOLOGISTS USED TO THINK.


In 1956, workers at the Fleur De Lys Farm in South Africa set a fire to clear brush and open new grassland for cattle. In the process, they inadvertently trapped three giraffes, including a mother and her infant. The flames, leaping into thorn trees and flaring up in bright, ten-foot-high bursts of sparks, were threatening the animals from three directions by the time Anne Innis, a Canadian zoologist, and Alexander Matthew, the farm’s manager, arrived.

The giraffes stood, apparently frozen in fear, as a worker, cursing and waving his arms, encouraged them to move. “Get out! Get out!” he shouted. “That way, you stupid brutes!”

Only when the fire was near enough to burn them did they shift into action, suddenly racing through the flames to an already burned spot of grass. There they seemed to calm down, the infant (six feet tall but wobbly and fragile, with the umbilical cord still attached) pausing to nurse. The mother lowered her head to reassure her baby with a gentle touch on the back. Soon, though, she ambled toward a fence at the edge of the burnt area, then stepped over it. The baby followed but was unable to continue past the barrier. The mother left for a moment, then returned. She looked at her baby on the other side of the fence, the pair of them now simply staring at each other. At last, she turned and strode off into a thicket.

For Innis, the drama was anguishing. “Doesn’t she realize the baby can’t get over the fence?” she asked Matthew.

“Giraffes aren’t very smart,” he responded.

“What’ll we do? Can we cut the fence?”

“No. That would scare both of them away, and anyway, it’s getting dark. We’ll have to leave them. Probably the mother will come back later.”

Innis spent the evening wracked with concern. Would the mother really return? Why had she left to begin with? The young researcher drove back to the burned-over area at dawn, hoping to see some signs of either animal, but she found nothing. She never learned what happened to the mother or her baby.

Do giraffes make bad mothers? That’s the view that Innis, by then Anne Innis Dagg, seemed to express in her first scientific publication, in 1958, after conducting a field study of wild giraffes. Another Canadian zoologist, J. Bristol Foster, who taught at the University of Nairobi, came to a similar conclusion from observing wild giraffes from 1965 to 1968 in Kenya’s Nairobi National Park. In 1976, the two experts published The Giraffe: Its Biology, Behavior, and Ecology—to this day, the most authoritative monograph on the species—which declares that the bond between giraffe mothers and their young is “remarkably weak.”

Part of the evidence for this surprising assertion comes from the zoo literature. There is, for example, a summary written in 1925 by Sol Stephan, general manager of the Cincinnati Zoo, titled “Forty Years’ Experience with Giraffes in Captivity.” It tells of the first birth of a giraffe anywhere in the Americas. The baby lived only six days, Stephan relates, his death “primarily due to the fact that the mother refused to nurse it and would strike at the young one whenever it came near her.” Another sad tale, written in 1966 by James Savoy, superintendent of the Columbus Zoo, describes a female giraffe that “trampled . . . to death” her firstborn and thereafter “repeatedly abandoned her calves.”

Foster and Dagg also point to field studies. The principal one is Foster’s regular observations at Nairobi National Park of an adult female standing “together with more than one newborn.” He would sight as many as five very young giraffes together in a group, sometimes accompanied by only a single adult female—or none at all. Calves as young as a month old could often be found more than a mile away from their mothers, and it seemed to Foster as if nursing ended altogether after about a month. Finally, Foster reports a seventy-three percent mortality rate for giraffes under a year old at Nairobi National Park.

Based on this sort of evidence, then, Foster and Dagg formed what I’ll call the weak-bond hypothesis. But there have always been good reasons to consider these experts’ conclusions skeptically. For one thing, the zoological literature they cite is incomplete and fails to consider the effects of captivity. The animals in the 1925 account were fed an unnatural diet and lived in unnatural confinement under unnatural social conditions. As for James Savoy’s 1966 report, it goes on to reveal that zoo management chose to remove the mother’s next three offspring immediately after they were born, without waiting to see whether she would abandon them or not.

The field work cited by Foster and Dagg likewise is limited; more significantly, it fails the test of evolutionary common sense. After all, evolution should prime any species to produce the best possible mothers given that species’ ecological circumstances. And in the case of mammals, mothering behavior based on an emotional bond with young offspring is especially important, because most newborns and youngsters pass through a highly vulnerable period. They depend directly on their mothers both for nutrition and for protection from predators—in the giraffe’s case, from lions, hyenas, and leopards. Giraffe mothers would need to be particularly attuned to the needs of their young: with a gestation period of around fifteen months, they are not prolific reproducers. If such mothers were really so neglectful, how could the species ever survive?

Later work published by other researchers has, over time, added a good deal to our understanding of giraffe mothering. Carlos Mejia, a Colombian zoology student associated with the Max Planck Institute in Germany and the Serengeti Research Institute of Tanzania, began, in the late sixties, an extended study of giraffes in the Serengeti National Park. He came to recognize some three hundred fifty individual animals. Two or three days a week, he traveled an established route through a hundred-square-mile study area and recorded which giraffes he saw where, and who was with whom. The remainder of his time was spent following individuals or small groups for a half day, a full day, or even, when the moon was full, a day and a half.

Mejia’s findings cast doubt on the weak-bond hypothesis. First of all, his single observation of a predation attempt showed how important mothers could be in defending their young: when a lion jumped a calf with the mother standing by, she immediately began to kick, driving the predator back. She and her young were then able to run away. Mejia also found that mothers who had just given birth remained secluded with their calves for the first few days, frequently nuzzling and licking them. He described one mother who attacked any other female attempting to approach during that seclusion period.

After the initial days of postpartum seclusion, Mejia reported, a giraffe mother would lead her calf into an area where there were other mothers and other tottering six-foot-tall babies. He was struck by how often the youngsters would approach each other nose first. They’d touch noses and sometimes lick each other’s noses before suddenly leaping apart. It seemed to him as if they were in a strange kind of playful nursery—an impression that seems congruous with the findings of a German researcher named Dieter Backhaus, who briefly studied giraffes in the Garamba National Park in northeastern Zaire (now the Democratic Republic of the Congo). Backhaus had described giraffe “kindergartens” consisting of a group of youngsters temporarily watched over by a single adult female.

Mejia, however, found that the young animals in such a group were often left completely on their own, typically out on an open hilltop. The mothers would wander off, browsing in some hillside thicket or woodsy gully, moving a half mile or even a mile away before returning near the end of the day, locating their own young, and nursing them. It must have seemed a little like mom going off to work, since the mothers left their youngsters at around nine o’clock in the morning, as the shadows shortened and the day warmed, then returned at around five o’clock in the afternoon, as the shadows began to lengthen again and the evening breezes moved in.

Giraffe calves in the group would spend much of the day lying around, occasionally nibbling at vegetation, their tolerance for solid foods beginning not many days after birth. And contrary to what Foster and Dagg had suggested, Mejia reported that the babies continued to nurse for about a year, not just a month. In the kindergarten, they usually nursed once in the evening, when their mothers returned, and then again in the morning before the mothers departed.

Why a giraffe kindergarten? It is possible that this system evolved because it enables the mothers to seek richer sources of nutrition—to go where the leaves are, in the thickets and woodsy gullies. But with the mothers away, how would the young giraffes in the kindergarten be protected from predators?

A few years later, Vaughan Langman, a zoology graduate student from Alaska, carried out a study that helped answer that question. Having traveled to the Timbavati Nature Preserve in South Africa, he outfitted a group of giraffes with radio transmitters and began tracking the animals—going out in a Land Rover at dawn, returning to his camp at dusk. In time he learned to recognize individual giraffes from a distance, based on the shape of a head, the style of horns, the manner of a gait. He got to know his animals well enough that he felt as if he were watching a daily film series. “Now leaving camp in the morning was exciting, and I couldn’t wait to see how the story or series of events would turn out,” he would later recall (writing in Smithsonian magazine). “Where would our giraffes go today? What other giraffes would be encountered on the way?”

Like Mejia, he observed that a giraffe mother does not wean or abandon her young after a month and challenged the notion that the bond between mother and infant is, somehow, “remarkably weak.” To appreciate the nature of giraffe mothering, Langman came to believe, people must first recognize that hoofed animals in general have evolved to use two different approaches for protecting their young: following and hiding. Follower species, such as wildebeests, produce youngsters who quickly learn to follow their mothers. Hider species—Grant’s gazelles, for instance—keep their infants hidden immediately after birth, with the mothers moving away, ideally deceiving any potential predators, and returning only to nurse. Infants move little and spend most of their time lying down: shadows in the shivering grass. Langman put giraffes squarely among the hider species. He noticed that when giraffe mothers return from their day of wandering and browsing, their young offspring will not leap up and run to them immediately, but instead remain hidden, lying down. The calves will allow the mothers to approach, then nudge and lick, before beginning to nurse.

Langman also observed what he referred to as “nursery herds”—groups of mothers and infants, not unlike the giraffe kindergartens described by Dieter Backhaus. As darkness fell, most of the animals in such a group would lie down. They would fold their legs beneath their bodies, curl their necks so that they could rest their heads on their haunches, and go to sleep. But one or perhaps two of the adult females would remain standing, sentries on the alert for predators. When they would become tired and lie down, others in the group would rise and take over the watch.

When a mother giraffe remained with a nursery herd during the day, she acted as a sort of babysitter, watching over her own calf but protecting the others as well. Should she become anxious at the sight of an approaching predator, she would find her own youngster and urge the calf to follow. She would run, the calf would run, and soon the other calves, witnessing the flight of the pair, would also run.

Foster and Dagg’s idea that giraffe mothers abandoned their offspring after a short while was based on incomplete observations. Better observations showed that the mothers were actually hiding their young. But what Langman still couldn’t fathom was why they were doing it for such a long time. Giraffe nursery herds could last for up to a year, while all the other species known as hiders kept their youngsters under wraps for a month at most. It looked to him like a deep puzzle without any clues.

During a conversation over a campfire one evening, a visiting friend asked him how giraffes were able to drink, given that their necks, though long, seemed not long enough to reach water at their feet. Langham replied that drinking required a sort of bending or spraddling of the legs, and that the awkwardness of the position made drinking at a watering hole dangerous for any giraffe, especially the already vulnerable young. He soon realized, though, that he had never actually seen a young giraffe drink. Were they drinking only at night? He observed watering holes after dark and concluded that they were not. It appeared that they were not drinking at all.

Langman suspected that here was the clue he was after, the scrap of knowledge that would lead him to the reason giraffes begin life with such an extended period of hiding. Youngsters nurse, of course, but given the intensity of the sun and the heat of the day, it would be difficult for them to survive without drinking. He had a feeling that the long months spent lying quietly in the grass had something to do with how they managed it. Before he could trust that intuition, however, he needed to know more about how much water a giraffe needs in the first place. And since an animal’s water requirements are related to temperature regulation, he felt he should also learn more about how giraffes maintain their normal body temperature.

These matters proved no less perplexing. An animal as large as a giraffe cannot keep cool by sweating, as humans do, because that would require too much water. And giraffes probably wouldn’t be able to regulate their temperature by panting, as dogs do. So much hot air would have to go up and down that long windpipe that the process would create more heat than it dissipated.

To get to the bottom of it all, Langman moved to Kenya after receiving his doctorate and started a new research project, this one in collaboration with the Kenyan physiologist Geoffrey M. Ole Maloiy. Monitoring a group of wild giraffes, the researchers discovered that the animals simply allow their internal temperature to fluctuate: it can shift by anywhere from five to eighteen degrees Fahrenheit on a typical day. In this way, they greatly reduce their water requirements. What makes such a trick possible is a large body. Giraffes are big enough that their body mass provides a high level of “thermal inertia,” which slows changes in body temperature.

The explanation made sense for giraffe adults, but what about their much smaller calves? An answer came to Langman one day as he was keeping himself cool by sitting in the shade of a thorn tree. He noticed that a young giraffe in the experiment, ordinarily reluctant to approach, had moved up close on the other side of a fence to find a bit of shade, too. “It occurred to me: the last time I had seen a young giraffe behave like that was when I was watching them in a nursery herd,” he wrote.

He finally had a theory for how young giraffes stay cool. And it explained why their hiding period lasts so long as well. According to Langman’s thinking, the animals are not staying in nursery groups just to hide from predators. They are also hiding from the sun—in the tall grass, in the shade of trees and bushes—until they acquire the necessary body mass and, thus, thermal inertia.

During a recent study of Rothschild’s giraffes at the Soysambu Conservancy in Kenya, a British researcher named Zoe Muller witnessed an event that made her reexamine everything she thought she knew about the relationship between giraffe mothers and their offspring.

One giraffe, known in the research project as F008, gave birth to an infant with a badly deformed rear leg. Would she abandon this crippled offspring? On the contrary, F008 seemed especially attentive, even, in Muller’s assessment, “doting.” At four weeks, the calf was able to stand and nurse, but had great difficulty walking and therefore spent most of his time standing in one place. The mother stayed very close to her compromised infant, never moving more than twenty yards away, and continually looked out for danger no matter what the rest of the herd happened to be doing. Since, as we have seen, mothers ordinarily hide their calves during the first four weeks of life and wander away in search of food, F008 was sacrificing her own well-being—probably going hungry, certainly reducing her foraging opportunities—so that she could watch over her handicapped baby.

One day in 2010, as Muller was driving her standard route through the research territory, she came upon seventeen giraffes, all of them female, all “highly vigilant” and “running around in apparently bizarre patterns.” When she stopped to watch, she saw that they were focusing their attention on a particular spot in a thicket. They would run over to that spot, stare, and then run away. Muller drove over to it and found, in an open, grassy area, F008’s crippled calf, who seemed to have died not long before from some natural cause. The mother, indeed, was one of the seventeen females running around.

Muller drove away from the carcass and parked in a place where she had a good view of the area. She stayed for the next three hours and reported in her notes that “all seventeen female giraffe ran around the area being vigilant, continually approached / retreated from the carcass and showed extreme interest in it.” When she returned that afternoon, she found the herd had expanded to include twenty-three females, who were now approaching the carcass and “nudging it with their muzzles, then lifting their heads to look around before bending down to nudge it again.” That evening, she discovered fifteen adult females, including F008, all of them “clustered” around the body. Although scavengers eventually made off with the remains, it was not until days later, and the mother remained in the area even hours afterward.

Yes, it’s a story filled with pathos, but it illustrates as well as anything I know one giraffe mother’s devotion to her young. It suggests, as well, a strong sense of empathy among the other mothers. The behaviors so carefully observed and described by Zoe Muller, in short, imply the existence of emotions that every human mother—and father—can appreciate.

Excerpted from Giraffe Reflections, text by Dale Peterson, photographs by Karl Ammann, published by the University of California Press 2013 by the Regents of the University of California. Dale Peterson teaches freshman English at Tufts and is the author of sixteen other books, including Jane Goodall: The Woman Who Redefined Man. Karl Ammann has been repeatedly named BBC Wildlife Photographer of the Year and is a Time Magazine Hero of the Environment.

 
  © 2013 Tufts University Tufts Publications, 80 George St., Medford, MA 02155