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"In the cosmos there are only eaters and the eaten. Ultimately, all is food." -HINDU UPANISHADS
There is an old English saying, "Manners Makyth Man." In fact, it is food that makyth man. For if we discount our basic physiology and anatomy, and those behaviors inherited through our genes, we truly are what we eat. We cannot survive without food, although certain individuals have claimed that we can. In the second half of the nineteenth century, young fasting girls captured the imagination of people all over Britain, especially one Sarah Jacob, a twelve-year-old who confounded doctors by refusing to eat or drink for two years. She became a tourist attraction, and in the end her parents agreed that a medical team could keep her under surveillance. It did not take long for her condition to deteriorate and soon she was dead. Her father, who had refused to offer her food, was sentenced along with his wife for manslaughter. It was never made clear who had been secretly providing her with sustenance during the previous two years.
More recently, in 1999, Ellen Greve set herself up as a New Age dietary guru who claimed that she had not eaten for five years,surviving instead on invisible crystals in the air. She advocated a twenty-one-day fasting regime linked with spiritual exercises, the details of which she sold to her more than 5,000 followers-it made some very sick and killed three of them. Eventually she was challenged and, with her reputation at stake, she agreed to stay in a hotel room where all comings and goings could be monitored. After three or four days, during which she definitely ate nothing, she collapsed and was admitted to the hospital. Unlike poor Sarah, she recovered, and tried to save face by complaining that the air in her hotel room was not fresh and could not sustain her as did the air in the Australian Outback. To which she fled-and I have not heard of her since!
It is true, of course, that people can fast for a surprisingly long time, but in the end everyone needs some kind of nourishment-it can be a surprisingly small amount-to stay alive. All creatures need food of some sort, although some can fast for much longer than humans can. Hibernating species like bears enter a state of slowed-down physiological processes and can survive a long harsh winter without feeding at all. The African lungfish buries itself in the mud of a drying waterhole, and waits it out until the next rains-which can be several years. A tick that I met was still alive after living in a jar, without food or water, for more than six years. It got very excited if you put your hand near and frantically waved its front feet and antenna-I suppose it sensed blood and I felt sorry for it. But these are exceptions. Most animals, like us, need food-and especially water-on a much more regular basis. And Planet Earth provides a staggering number of items on the menu-almost everything is food for someone or something. In nature there are thousands of fascinating stories, plots and counterplots, that revolve around this basic need for food.
Some animal species have evolved the most extraordinary ways to find, catch, prepare, or digest the substances, plants, or other animals that keep them alive. Live prey is chased, stalked, poisoned, snared. Spiders are incredibly skilled in enmeshing, trapping, or hunting their prey. There is even one spider who puts a sticky blob on the end of a short strand of web and then, like a little cowboy with a lasso, waves it around her head at passing flies. The archer fish waits for a fly to land on a branch overhanging the stream, then launches a mouthful of water with deadly aim, knocking his dinner into the water. Ant lion larvae dig funnel-shaped pits in loose sand, lie in wait at the bottom, and hurl grains of sand when they sense some hapless insect struggling at the rim, causing it to lose its footing and skid down to be seized in strong mandibles. Many creatures, once they grab their prey, inject poison that incapacitates their victim. This enables them to eat creatures larger and stronger than themselves. There is even a family of plants that lives on animal foods. Pitcher plants lure insects into pitcher-shaped leaves filled with a delectable enzyme soup in which the prey is gradually digested and absorbed. The sundew has sticky leaves that close shut over unwary insects stopping there to feed on tempting drops of nectar-they are then gradually digested.
Different kinds of animals use different structures and methods to achieve a similar goal. To reach the nectar buried deep within a flower, insects such as butterflies and bees use a long proboscis; hummingbirds and sunbirds use long thin beaks. To feast on succulent termites or ants that are hidden underground, armadillos and anteaters have evolved strong digging claws and long, wormlike sticky tongues that snake down into the mound; chimpanzees fish for them with straw tools. Elephants reach food high up in a tree with their trunks, giraffes make use of their long necks, other creatures get up there by climbing or flying. Animals as diverse as spiders and lions hunt by stealth, stalking their prey, or hiding and pouncing. Others, like cheetahs and falcons, rely on short bursts of speed or, like hyenas, show amazing powers of endurance in the chase. Prey may be located by sight, hearing, scent, vibration, or echo location.
In turn, many plants and animals have taken equally ingenious measures to protect themselves from becoming food. Insects, according to their species, have evolved to resemble the bark of trees, dead leaves, flowers, twigs, and so on. There is a caterpillar at Gombe that looks exactly like a bird dropping. Caddis fly larvae make themselves little tubes to live in, then camouflage them by sticking on bits and pieces of the surrounding vegetation. Trapdoor spiders use the same technique to disguise the hinged plugs that close the entrance to their burrows. Some insects have brilliant colors but taste revolting. After one experience the would-be diner will avoid others of their kind forever. And there are other insects that actually taste delicious but that have evolved to resemble the noxious bugs so closely that they are avoided!
Many of the larger herbivores are arrayed in spots and stripes that blur their outline and make them hard to see. Octopuses can even change color, the better to blend into their surroundings. A diverse collection of creatures-porcupines, hedgehogs, puffer fish, sea urchins, hairy caterpillars, and so on-protect themselves with spines, quills, prickles, or stinging hairs. Others develop a tough outer armor, like tortoises and turtles, armadillos, and countless insects. There are some creatures who have developed poison, administered through the teeth, as in snakes, or stings as in the cone shells and stonefish, that, while primarily used to immobilize prey, is also extremely effective in repelling would-be predators. The same is true for the electric shocks administered by stingrays, electric eels, and so on.
As for the plants, they and their seeds are protected in a hundred different ways, by thorns and prickles and stinging itching hairs and foul toxins, and hard outer coverings. Many plant products, however, are meant to be eaten. Succulent fruits have been designed as high-quality food so that fruit-eating animals are more than happy to play a role in seed dispersal, carrying them away in their stomachs for eventual excretion elsewhere. Some seeds cannot germinate until they have passed through the stomach and guts of an animal. Many plants have developed alluring fragrances to attract insects, certain birds-and even a species of bat-to feast on the sweet nectar secreted in their flowers. These gourmets transport pollen from one plant or tree to another, thus playing a vital role in the propagation of the species.
Internal organs and digestive systems have adapted to cope with all manner of foods: tough, fibrous vegetable matter, leaves full of toxins or covered with spines, putrid carcasses, bones, and so on. Jaws and teeth of different size and strength enable their owners to crush, tear, or chew whatever it is that nature has planned as their diet. Birds are equipped with a fascinating array of beaks, each designed for dealing with the food the bird is born to eat. Hyenas have teeth and jaws so strong that they can crunch big bones and digestion so incredible that they can extract some nutrients from ancient carcasses.
By and large animals can only eat what they were born to eat: A giraffe could not survive on meat any more than an eagle could survive on leaves. Many species are quite specialized in their dietary needs: Koala bears must have eucalyptus leaves, giant pandas need their bamboo, the larvae of hunting wasps can only survive when fed the paralyzed bodies of particular species of spider or caterpillar. Other creatures are more catholic in their tastes, and many are omnivores, surviving on a mixed diet of plant and animal foods.
Thus, to a large extent the structure and behavior of animals has been determined, during the course of evolution, by their need to get adequate food of the right sort. And there can be little doubt that food-its acquisition, preparation, and consumption-played a role in the evolution of our own species. Like many of our primate relatives, we humans are omnivores. So are chimpanzees, from whom we differ genetically by only about one percent. Many people are interested in chimpanzee diet for the insights it may give us into the food preferences of our stone age ancestors. Chimpanzees are primarily fruit-eaters-they have long mobile lips and special ridges on the insides of their cheeks that enable them to suck and squeeze the juice from their food. But they also eat leaves, flowers, and stems, as well as leaf buds, seeds, and nuts that are rich in vegetable protein. They enjoy animal protein, too, and at certain times of year consume large numbers of insects, primarily ants, termites, and caterpillars. And at intervals throughout the year they hunt small- and medium-sized mammals; meat makes up about 2 percent of their annual diet at Gombe.
TOOL USE AND HUNTING
For anthropologists with an interest in human evolution, such as Louis Leakey, the most significant observations that I made at Gombe, in the early 1960s, were those that documented, for the first time, chimpanzee tool-using and hunting behavior. I can never forget the first time I saw a chimpanzee using tools. I was trudging through wet vegetation after a frustrating morning-for most of the chimpanzees were still shy, running off whenever they saw me. Suddenly I saw a black shape squatting by a termite mound. Peering through the leaves I saw that it was David Greybeard, the male who was beginning to lose his fear of the strange white ape that was me. I saw him pick a grass stem, poke it down into the mound, wait a moment, then pull it out coated with termites. These he picked off with his lips. I could see his jaws working and hear the sound of scrunching. I had seen a wild chimpanzee using a tool!
It was such an exciting observation that afterward I almost thought I must have imagined it. But a few days later I saw both David Greybeard and his friend Goliath using grass stems to feast on termites. And I watched as David broke a leafy stem from a nearby bush and stripped off the leaves-modifying an object to suit it to his purpose. Not only had I observed a wild chimpanzee using a tool but I saw one actually making a tool! Back then it was thought by scientists that only humans used and made tools. This, it was held, differentiated us from the rest of the animal kingdom more than any other criteria. "Man the Toolmaker" is how we were described in the anthropological textbooks of the time. I sent a telegram to Louis Leakey. "Well," he replied. "Now we must redefine Man, redefine Tool-or accept chimpanzees as humans!" Subsequently I would observe the chimpanzees using long peeled sticks to feast on army or driver ants, scrumpled-up leaves to sop water from hollows in tree trunks, and a variety of other objects for different purposes-most of which were in the context of obtaining food.
It was David Greybeard who provided me with the first evidence that chimpanzees sometimes eat meat-prior to my study it had been assumed that chimpanzees were vegetarians. On that first occasion I saw David feeding on a baby bush pig. He was sharing the flesh with an old female who sat close, begging, while her child, unsuccessful in getting a share from her elders, made repeated sorties to the ground to snatch up scraps. She was charged each time by the infuriated adult pigs and had to rush back up the tree, screaming loudly. A few weeks later I actually watched a successful hunt. A small group of red colobus monkeys had taken refuge at the very top of a tall tree that rose up out of the canopy. This was a mistake, for in such a situation they are relatively easy to catch. Several adult male chimpanzees took up positions in the surrounding branches, effectively cutting off the monkeys' escape routes. Then an adolescent male climbed slowly up the trunk, leaped toward a female monkey who had an infant clinging to her breast, seized the baby, and rushed away with his prey. One of the adult male chimpanzees seized the kill from the youngster and, in a short space of time, the carcass was torn into pieces by three big males in a positive frenzy of noisy excitement. The adolescent hunter joined the females to beg for scraps.
Over the years we have observed many instances of sophisticated cooperation during hunts, and a good deal of food sharing. We now know that chimpanzees hunt for meat throughout their range in Africa-or at least in all places where they have been studied.
NEW LIGHT ON HUMAN EVOLUTION
Louis sent me to learn about chimpanzees in the wild because he hoped it would give him new insights concerning the behavior of our earliest ancestors, and theirs. He argued that if there were similarities in the behavior of modern chimpanzees and modern humans, those behaviors were possibly part of the repertoire of the apelike creature with hominid characteristics, ancestral to both humans and chimpanzees, that lived about seven million years ago. And, if so, then those same behaviors were probably inherited by prehistoric human beings also.
The observations made at Gombe suggested, for the first time, that prehistoric humans may have hunted for meat and used primitive tools made of leaves and sticks long before the first hammer stones and hand axes were made. I love to imagine those earliest ancestors kissing, embracing, and holding hands, visualize their excitement after a kill had been made, picture them using simple tools to help them with the gathering and preparing of their food. Louis was in the forefront of this kind of thinking, and his vision paid off: Most textbooks now refer to chimpanzee behavior when speculating on the behavior of our prehistoric ancestors.
Today it is generally accepted that although the earliest humans probably ate some meat, it was unlikely to have played a major role in their diet. Plants would have been a much more important source of food. This is true of almost all the hunter-gatherer peoples whose way of life lasted into the last century. The exceptions are when a group of people has moved into an environment that is, for at least part of each year, hostile to plant growth. This is true for the Inuit and the Alaskan Eskimos, and those people who moved into the arid plains. But whatever our prehistoric ancestors ate or did not eat it is safe to assume that the search for food, and the competition with other prehistoric creatures, played a key role in human evolution. For one thing, it was the fact that their diet was unspecialized that enabled our apelike forebears to move out from the forests where, it is assumed, they originated.
Early humans shared the African savanna with many formidable creatures, including giant, gorilla-sized baboons. There was possibly intense competition between them, just as there is today between chimpanzees and baboons at Gombe, where the two species feed on many of the same foods. One such is a tennis-ball-sized Strychnos fruit with a very hard shell. The baboons are easily able to break these open with their strong teeth and jaws, but the chimpanzees cannot. However, the chimpanzees have learned to crack the fruit against a rock to get at the flesh. In West Africa chimpanzees have even developed a hammer-and-anvil technique, cracking open hard-shelled nuts by placing them on rock or root "anvils" and pounding them with rocks or clubs. This innovation gives them access to a rich food supply that is safely out of reach of most creatures. It seems reasonable to suppose that prehistoric hominids also used rocks not only as weapons, but to crack open hard-shelled fruits and nuts.
Excerpted from Harvest for Hope by Jane Goodall Gary McAvoy Gail Hudson Copyright © 2005 by Jane Goodall and Gary McAvoy. Excerpted by permission.
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