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The Elephant's Secret Sense The Hidden Life of the Wild Herds of Africa
By Caitlin O'Connell Free Press Copyright © 2007 Caitlin O'Connell
All right reserved. ISBN: 978-1-5946-3018-7
Chapter One LISTENING THROUGH LIMBS
Do not go where the path may lead, go instead where there is no path and leave a trail.
- Ralph Waldo Emerson
I always hate to leave Etosha, but it was early August and the winds were picking up. It was time to pack up the site and head north. Sitting in the back of my truck, I looked through my binoculars at the scrubby horizon dappled with giraffe necks, trying to work up the energy to get my equipment organized when I heard a thick, leathery, swishing sound right next to me. I looked up to see 100 tons of pachyderm pass by, almost tiptoeing, heads bobbing in their Nordic Track-style gait. It was Broken Ear and her family, a group of twenty elephants, headed purposefully toward the water.
I noted when Broken Ear arrived and watched as her family assembled around the water. Being the matriarch, Broken Ear occupied the outflow of the artesian well, which was controlled in the dry season to sustain the large number of animals that depended on it to get through this difficult period. The dominant elephant always got the best water.
Broken Ear took a few long draws, rolling up her trunk and placing the water far back in her mouth, head tipped up. A few splashes escaped back into the pool. The howling gusts of wind had stopped, so I could hear the intermittent trickling of water escaping thirsty mouths. They were returning to the waterhole after their visit had been cut short the day before by the arrival of another family group led by a very intolerant matriarch that I called Collar.
Once the little ones had had their fill, they started to play. Young elephants are just as mischievous as lion cubs, always testing their boundaries with adults and jockeying for rank with siblings and other relatives. They stood at the pan's edge, knee-high in water, and tipped over onto their sides to make as much contact with the mud as possible. Then they began to wallow, swatting at each other with their wet-noodle trunks. Their mouths were turned up in what seemed to me like smiles as they wailed and cavorted in the water. The mothers merely looked on and continued drinking.
Reluctant to break camp, I savored the moment. I jealously guarded my visits to this splendid waterhole that the Owambo people called Mushara, after a tree common to this sandy forested habitat, or sandveld, a large terminalia with papery magenta pods (Terminalia prunoides). Mushara is located in the eastern corner of Etosha National Park, Namibia, one of a few waterholes restricted to the public, with the added benefit of having a protected cement lookout, which provided me with a great vantage for my elephant studies. I had a few other favorite waterholes where I would sleep, either in the back of my truck or in a hide. But I had developed a special bond with Mushara because of its remoteness and the number of elephants visiting on a daily basis. As much as I enjoyed the isolation, I was conscious of its potentially negative effect on my preception of reality. I was looking forward to being clean again, having not been able to shower for more than a week, but I was also dragging my feet about leaving the tranquility.
I was not looking forward to returning to my life in the north of the country, the Caprivi, where, despite its remote location, an exhausted community game guard might knock at my door at any minute, having bicycled 12 miles in the heat to assuage the anger of his fellow villagers to report another incident of a crop-raiding elephant. I would miss the elephants of Mushara, which were more isolated from the threats of war and civilization, and head to a place where they were different animals altogether. Many elephants in the Caprivi were still reeling from a war-torn past, exposed to land mines, automatic weapons, and poaching, partly to feed the hungry Angolan soldiers for the last twenty years. And at Mushara, I, too, could be a different person.
I first came to Etosha National Park in 1992, contracted by the Namibian Ministry of Environment and Tourism to study elephant movements, demography, ecology, behavior, and interactions with humans. My partner, Tim, and I were stationed in the Caprivi region of Namibia. This "day job" allowed us to spend our winters in Etosha, where Tim would analyze the movement data he collected from nine elephants fitted with satellite and radio collars while I would have the luxury of focusing solely on elephant communication and behavior. I hoped to use that research to help farmers in the Caprivi to prevent elephants from raiding their crops, which sometimes amounted to a whole year's worth of food consumed in one fell swoop.
It was during these off-seasons of my initial three-year contract that I was able to spend countless hours by myself watching elephants at Mushara waterhole. I spent most of my time in the hide, a 10-foot-square cement bunker 33 feet from the water, with about 7 feet of its height buried in the ground and a pillbox slit facing the waterhole. It afforded a splendid view of elephants at close range but was very limited in terms of an overall picture of the negotiations made around the perimeter as to which herd was going to enter the clearing and when. But it allowed me to be closer to the action, and it was safe from lions or even a curious bull wanting to investigate the back of the truck. Once inside, however, I was committed for the night. It was me and my empty peanut butter jar, a makeshift but highly valued chamber pot in the bush.
I stayed in the dank bunker for as long as physically possible, usually about a week at a time. The isolation allowed me to reflect on the elephants' natural rhythms and to notice many behavioral patterns that had never been previously documented. These patterns formed the basis of my thinking for the next fifteen years of my career as a scientist. Eventually, once I learned to slow my own sense of time, adapting it to the deliberate, meditative pace of an elephant, I started to understand the patterns I had been observing.
Occasionally, Broken Ear would turn herself in a particular direction and freeze, sometimes with ears flat against her head and sometimes with ears held out, looking like a satellite dish, scanning the horizon. As she scanned, she seemed to cue the other adults to follow her lead. When she alerted the others to pay attention, they all oriented in the same direction, froze again, sometimes with ears flat, leaning forward, one front foot propped up on the toenails. Other times, they extended their ears, sometimes keeping toenail contact with the ground, sometimes lifting one front foot completely off the ground, swinging it front to back. It's not surprising that the matriarch would be wary at the waterhole and that she would be using her ears to try to detect any unusual sound, but what were these elephants doing with their feet?
I scanned the horizon and saw a large bull heading in on the southwest elephant trail, about a half mile away, ears fanning as he lumbered along. The vigilant cows shifted positions, several of them facing in the direction of the incoming bull. But their ears were not outstretched in a listening position. Could they have sensed his approach through the ground?
I became very familiar with this particular way that elephants seemed to be listening with their feet. My curiosity grew as I watched an elephant assume a position with its ears flat against its head, occasionally accompanied by leaning, with a foot lift or toenail contact. It was known that these animals used their ears like a parabola, scanning back and forth while remaining still to listen to low-frequency sounds from other distant elephants, but I had never read any studies describing an elephant's ears positioned flat against its head while freezing and listening.
Other scientists had thought that the leaning behavior was a resting position and foot swinging an act of indecisiveness. This is probably the case some of the time, but there were also some times where it appeared as if the elephants were actually using their feet to sense something in the ground. After seeing these behaviors, I would notice the arrival of a new herd or a lone bull or an approaching vehicle. When more than one elephant engaged in this freezing/leaning/shifting at the same time, it seemed as if the whole herd were using their feet to detect a signal.
I knew about the process of listening through limbs, which is found elsewhere in the natural world. Before signing on with the Namibian government, I had studied this phenomenon - known scientifically as seismic communication - in insects. In a sense, I was only going from the very small to the very large, having spent endless hours in a small soundproof chamber recording the seismic love songs of a unique group of Hawaiian planthoppers. It may be hard to understand my fascination, but I observed some extraordinary behaviors occurring on a little koa twig rigged to a gramophone stylus - behaviors that seemed very similar to those of these elephants.
When I would play the female planthopper's seismic call through the twig, the male would immediately press its weight down and would sometimes even lift up a leg or two, then inch forward, responding with its own seismic call, then freeze again, "listening" and perhaps attempting to locate the dummy female. I never could have imagined it sitting in that booth, but these little planthoppers and their extraordinary songs handed me a hypothesis for elephants that was so unexpected and controversial, I found myself occupied with the challenge of proving it over the course of the next decade.
Since many other species are known to transmit their vocalizations either through the ground or some surface such as a plant, it was not a completely ridiculous proposition that elephants might do the same. Many scholars have described how insects and other arthropods communicate by striking the ground or by coupling their vocalizations with a substrate. Other more complex animals such as fish, amphibians, lizards, snakes, and even crocodiles exploit this form of communication, too. However, the only mammals in which the mechanism has been well documented are small rodents such as the blind mole rat, the kangaroo rat, and the golden mole (though there is evidence that elephant seals may also share this skill).
Seismic communication may sound complicated, but it simply means a sound wave used for communication that travels within the surface of the ground as opposed to the air. Although it seems stiff, the earth is actually elastic. Tossing a stone across its surface, for example, would cause it to ripple, just like the surface of water. These surface ripples can be imagined on a larger scale such as in the case of earthquakes.
On a much smaller scale, surface waves from the slightest bouncing up and down of a hungry spider at the edge of her trap become a dinner bell. Similarly, a plant stem supports the same types of waves for a lonely planthopper looking for a mate. I discovered that the earth also acts as a sounding board for the elephant. But I knew it was going to be difficult to be certain and then convince others in my field that a large terrestrial mammal might be communicating seismically.
The concept isn't all that different from a person putting an ear to the railroad tracks to listen for a distant train, literally keeping an ear to the ground. It was illustrated in the movie Dances with Wolves when Kevin Costner listened to the ground to feel the tremors from a stampede of distant tatonka or American bison, a technique used by Native Americans to prepare for a hunt. Or, for Lord of the Rings fans, Aragorn putting his head to the rock to listen for the distant thumping feet of the fearsome Urukai as they bore Merry and Pippin away to Isengard.
A student of a Native American tracker once told me that in order to feel the pressure waves from the heartbeats of their enemies, the Apaches would hold the hairs on the backs of their fingers up to the windows of their enemies' houses. That's pretty subtle stuff. However, maybe it is not so subtle a sense for those who have a real use for it. There are institutes for the hearing impaired, for example, with special wooden dance floors designed to facilitate the hearing of music through feet.
Since all primates have the ability to detect vibrations through specially adapted pressure receptors in the hands, feet, and lips, among other places, it's not at all surprising that we have the ability to detect vibrations. If we really paid attention, or perhaps if those vibrations were a more important source of our long-distance communication, we would doubtlessly be able to detect vibrations much more acutely. In a quieter era, low-frequency drums or instruments like the didgeridoo might very well have been an important means for sending a message to a distant receiver through the ground. For those who need this communication channel, such as the hearing impaired, the area of the brain that processes touch, the somatosensory cortex, can even take over the function of the auditory cortex, providing that much more area dedicated to vibration detection.
For the elephants in the wild, I was beginning to think that perhaps seismic signals played an important role in their complex communication repertoire. Perhaps they, too, had honed their skills at detecting vibrations to better interpret their world.
The looming bull came and went. He was old and in musth, with all the telltale signs of this hormonal state: a sappy secretion streamed from his temporal glands and he dribbled urine, which left a sheen of crusty green algae around his penis sheath. He did the rounds, searching for an estrus female. With each, he would test the cow's vulva with his trunk, inspect any urine patch in the sand, and roll his trunk tip to the back of his mouth to reach the duct leading to the vomeronasal organ, a special hormone-sensing structure that let him know if a female was in heat. With mouth wide open, he looked like a dirty old man, testing the tannins of the progesterone equivalent of red wine with his flehmen grimace. Nothing smelled interesting, so he sauntered off.
At this point, Broken Ear also decided it was time to leave. She stopped drinking and stepped away from the waterhole. She oriented toward her destination, emitted one long, low rumble, and waited there. Although two others rumbled in response, nobody appeared to make a move, and after standing still for about thirty seconds, she repeated her "let's go" rumble. After several of these rumbles, a few of the other cows finally decided to address this call to action and slowly lined up behind her. The group then meandered off to another foraging spot.
I watched Broken Ear and her family disappear into the tree line and then returned to my packing, occasionally scanning the horizon for possible new visitors. After coiling some wires and packing up my camera equipment, I watched a dust devil on the horizon and tried to decide whether it was going to blow through camp. While my eyes followed its course, I suddenly caught sight of a chalky gray mass lurking in the bush just beyond the waterhole clearing.
It was a new herd, consisting of a young matriarch and most likely her two younger sisters and their calves. They stood there for the better part of an hour, smelling the air with their trunks held high, mouths agape with anxiety, pitting thirst against caution. Could she have been waiting for Broken Ear to leave? I hadn't noticed that Broken Ear was not amenable to sharing her waterhole visits. Except for Collar, so named because she wore a satellite and radio collar as part of a movement study conducted by park researchers, elephants in this remote region of the park seemed to be accustomed to sharing their waterhole visits with at least one other herd. It was clear that no elephant wanted to contest Collar's challenges, not even by sneaking around to the overflow of the well that formed a flat pan of water.
Collar spent many of her visits simply holding off other elephants so that her family could have sole access to the water. Because of her tenacity, I often wondered how she managed to get enough to drink. And what had happened to her that she would view sharing as a threat when other herds appeared to have adapted to the routine? Another collared elephant in my more recent studies displayed similar behavior and became known as the "Collared Bitch" by my colleagues, who were most entertained by her defensiveness. Eventually, I decided that she needed a kinder name and began to call her Margaret Thatcher. It appeared that she was simply acting in the best interests of her family.
Seeing this new herd's reluctance to approach the water with a strange vehicle parked near the edge, I began to think that perhaps I was the cause for concern. At this point at the end of winter, most elephants in this lonely eastern region of the park would have seen the truck at some time during the season. Maybe these were stragglers from the west where all the natural pans had dried up.
(Continues...)
Excerpted from The Elephant's Secret Sense by Caitlin O'Connell Copyright © 2007 by Caitlin O'Connell. Excerpted by permission.
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