This does not necessarily mean that something bad happened to him, although the fate of the leaf was puzzling. A small maple tree was within his walking distance. Perhaps he went there to pupate. We looked at the tree, but it was in a large brushy thicket and we lost hope of finding something as small as a caterpillar hanging upside down.
Monarchs are amazing creatures, and have been carefully studied. They begin life as eggs the size of the dot on the i in caterpillar. When they hatch, they’re the size of the l in caterpillar. They enlarge, of course, at first eating only the tiniest hairs of the milkweed, taking more substantial bites as they grow bigger. A caterpillar’s skin is not like ours but is more like a flexible casing, not quite so much a part of the caterpillar as a container in which he grows. Meanwhile, a new skin is forming inside the casing, which soon becomes too tight, so the caterpillar gets rid of it, wriggling out of it and rubbing it off his face with his forefeet, just as we would use our hands. The final skin is the chrysalis in which he pupates. Our monarch was about two inches long, thus was probably about two weeks old, and would have shed his skin about five times since hatching.
His was the generation that would migrate, and thus he would live longer than the earlier generations of that summer, or he would if he survived the migration, which must be a devastating experience for creatures so light and so small. Now and then during the weeks that followed, small flocks of monarchs would appear on our flowers, where they would eat for a while and then depart—evidently migrants on their way to wherever it was they hoped to spend the winter. They would fly off to the south, their little bodies tipping this way and that as the light breeze took them.
Our prevailing wind is from the southwest, and would carry them toward the coast. Once there, they would need to follow the shoreline and not let the wind carry them out to sea. Some of them manage to do this—the Atlantic Coast is a flyway for monarchs—but I cannot picture how they manage with their tiny bodies that weigh about the same as milkweed seeds, and their little gossamer wings. We didn’t know if our caterpillar was among those migrants, but he could have been. We watched television to see what the weather was doing, glad when the weather was warm and calm, worried when a storm came up the coast from Georgia. On September 28, as Hurricane Kyle was moving toward us, one lone monarch appeared and flew back and forth across my office window all afternoon. The window wasn’t thirty feet from where we first saw our monarch caterpillar. Was it him, all alone, with a hurricane coming? We hoped it wasn’t—we had last seen him around the end of August, and this was almost a month later. But it might have been him—he might have emerged from his chrysalis and stayed around. But wherever he was, we wished him well—him and all the other monarchs out there, struggling on with their astonishing, important lives.
If a goal of an organism is to live, some trees on my land were meeting the goal spectacularly. In 2008, Anne McBride of the Monadnock Conservancy and Brian Hotz of the Society for the Protection of New Hampshire Forests discovered—not a mile from my house on land that wasn’t mine until 2003—a grove of rare, black gum trees between four hundred and six hundred years old. I began to visit that piece of land as soon as I owned it, but as usual, I must have been looking for animal signs and didn’t take note of the trees. I was amazed and elated to learn of them. When Columbus set foot on our continent, those trees were saplings. When the first colonials began to clear what was later to become my patch of forest, those trees were three hundred years old. But here was a mystery. In the woods not far from where they stood were the ruins of an old mill and the stone foundation of a small house, and also miles of stone walls that once surrounded pastures. How had these trees survived in the presence of so much human activity focused solely upon farms and field making? I consulted some forestry books that belonged to my father, and in one of them—American Forest Trees by Henry A. Gibson, published in 1913—I learned that the wood is difficult to cut because the grain goes in different directions. When the area that became my land was first cleared, there were no chain saws. People cut trees with a two-man saw or, more likely, with an ax. But a dense, complex grain will buckle a saw and prevent an ax from dislodging a chip no matter where it strikes. In the book is the photo of a frustrated woodcutter who, with his ax, has hacked into a black gum dozens of times with no better result than dozens of ax marks. The tree remains rock-solid. Surely this explains the presence of these black gum trees. The old farmers didn’t cut them down because they couldn’t.
Gibson tells us that the foliage of these trees is spectacular in autumn. I have yet to see them in the autumn. Gibson also tells us that in October, they drop little fruits that no animals will eat. He doesn’t say why, and doesn’t pursue the question. But there is a question, a very important question, because the usual reason for a tree to make fruit is so someone will eat it, swallow the seeds, and carry them off to pack them in dung and drop them far away. If a tree is making fruit that no one seems to want, it suggests that the tree had a particular species in mind to do this service, and the species is no longer around. One thinks of the dodos, who lived on the island of Mauritius until the 1600s, when they famously became extinct. The tambalacoque trees of Mauritius are following the dodos into oblivion because, it is believed, the only creatures who would eat their fruit were dodos, and the seeds had to pass through the dodo’s gut before they could germinate. The tambalacoque trees on Mauritius today have outlived the dodos by four hundred years, but they no longer reproduce, or not often, or sometimes only with complicated human assistance.
However, the black gum trees won’t be needing human help, or, in fact, the help of any animal. Their groves contain trees of different ages, some younger than others, which means they are reproducing on their own. They send up sprouts from their roots or stumps, sprouts that become trees eventually. As far as I know, all trees can make sprouts, but most of them don’t depend on sprouting for existence, certainly not in New Hampshire. Maple trees have winged seeds that the wind carries, oaks have acorns that the squirrels plant, wild cherries have fruit that birds eat, and so on. But according to the New Hampshire Natural Heritage Inventory of April 2000, it was the tendency of black gum trees to produce sprouts (plus their tolerance of hundreds of years of hurricanes and other disasters) that explains why relatively young black gum trees are found amid the truly ancient ones. And because a sprout rising from a stump or root is not the offspring of the original tree but an extension of it, a black gum that today is six hundred years old may have sprouted from a stump that was already six hundred years old, hence the total age of that particular tree could be 1,200 years or older.[3] That being so, who knows for whom the fruit was first intended? Someone must have eaten it, but whoever it was must have vanished in the very deep past. And still, the black gum trees keep fruiting.
The older trees are tall, of course, but seem surprisingly thin, with straight, spiky branches and deeply furrowed bark. One of the oldest black gum trees in my forest has a large hole in the trunk about ten feet up, the home of a fortunate animal. The botanical name of their species is Nyssa sylvatica, or nymph of the forest. Few things could be less like nymphs than these tall, ancient beings with their heavy, rough bark. Nymphs of the forest? Who thought of that?
Then there were the oak trees. Those, I thought I knew. Ten of them were within thirty feet of my house and, unlike the black gums, they were only in their eighties or nineties. They appear in a portrait of my mother, painted in 1937 by her closest friend, the artist Grace Reasoner Clark, who posed my mother outdoors with these trees behind her. My mother was thirty-nine, I was six, and the trees were graceful little saplings. Today, they are ninety feet tall and sixty inches around at chest height, the offspring of a massive parent that once stood in the midst of where they are now, but, unlike the black gums in the forest, did not survive the hurricane of 1938. My grandmother and I were looking out the window and saw this oak tree fall. First the wind pulled off its leaves, then made it le
an sideways, then pushed it over with a tremendous crash that vibrated the house. The tree was still alive but doomed, lying on its side with its ruined branches on the ground, their few remaining leaves still trembling, and the giant disc of its roots still holding earth, exposed and gaping. After the hurricane passed by, my grandmother and I went to look at it with pity. If we could have stood it up again and saved it, we would have.
The offspring of that tree grow close together along a stone wall, where the parent shed its acorns. The largest one is on the east edge of the grove where it gets the most sunlight. A maple grows right beside it, an intruder that to some extent blocks the sun. So the oaks compete with one another and with the maple. Trying to live as well as they can, they extend a branch or two far out over the driveway where sunlight can reach the leaves. The largest, eastern tree does that the most. I hate to say this, but over the years we have sometimes had to cut the branches because they scrape the tops of delivery trucks and the drivers complain. The tree will then promote another branch, encouraging it with lots of nourishment, and in a few years, that branch will also be over the driveway. Like the hand of a supplicant, it will reach for the sun until it also becomes large and heavy. It then begins to sag, scrapes the top of a delivery truck, and we cut it, but we aren’t happy about it.
These trees withheld acorns in 2007. I somewhat resented that, although they were only looking out for themselves, just as they should, but otherwise I took them for granted and seldom thought about them except to wonder if, in a strong wind, one of them might fall on the house. However, in the autumn of 2008 I began to take more notice because, in contrast to the previous year, the trees were developing acorns. They would feed the deer and the wild turkeys. Unlike the black gum trees with their unpopular fruit, the oaks fed almost everybody, including, of course, the squirrels who, in contrast to the other acorn predators, were helpful and planted some of the acorns for them. A squirrel will bury many acorns to eat later, but will not find them all. These will grow into trees and one day will produce more acorns that will feed more squirrels. That’s the oak tree’s reproductive strategy. It’s not as fancy as Cordyceps, but it works.
One day, the acorns began to fall. We heard them pounding on the roof. Interestingly, we would hear all kinds of clattering for a while, then as much as an hour of silence, then suddenly much more clattering. I hadn’t noticed that before and I went to examine the oaks more carefully. Up in the crown of the largest, easternmost tree I spotted a cluster of six or seven acorns. Then suddenly I heard a pop and saw them burst away from their footings all at once. They didn’t just drop—they flew off, as if in response to pressure. Soon another cluster popped and fell. Within moments, the next tree to the west began to do this, and then all were doing it. Acorns rattled on the roof of our house like machine-gun fire. And just as suddenly, silence.
What had I seen? The trees beside which I had lived for much of my life were doing something I had never noticed. I couldn’t give myself high marks for observation, but at least I thought to notice if the wind was blowing. It wasn’t. The trees were doing this all by themselves. Since I am always looking for intent in life-forms, asking myself what does this plant or animal want (or, to seem a bit more scientific, what is the purpose of what it’s doing), it came to me that the trees might be coordinating. They were, after all, siblings. And trees do coordinate—the year before, the oaks had coordinated to withhold acorns, and I’ve heard that if insects attack a certain kind of tree in a grove, the tree releases a pheromone into the wind to warn the other trees who then produce a toxin and are ready for the insects when they come.
What could be more gripping? Were the oaks really coordinating to fling out their acorns, or was I imagining? I kept watch and came to the conclusion that while the coordination could possibly be caused by an unknown environmental factor, the acorns really did fly off. It made sense. If the acorns dropped straight down, they might land on the thickest part of their parent’s roots, where they would have trouble inserting their own roots. Better to land a few feet away. But the most interesting thing of all—although I can hardly believe this myself because it negates the possibility of the environmental factor (and I won’t be surprised if others can’t believe it either)—is that the biggest oak to the east seemed to initiate the action. Was this the oldest sibling, showing the others how it’s done? Not likely. Even so, whenever I was there to watch this, the tree to the east went first.
I made a feeble effort to learn more about acorns, but didn’t. I did learn something about leaves, however. I learned that oaks originated in the tropics, which is why their bark is relatively smooth, like that of tropical trees. When the world’s landmasses readjusted themselves, the oaks rode their continent northward and found themselves in a different climate. In the tropics, they would not have shed their leaves, and this is why, even today, they are among the last trees to lose dry leaves in the fall. Beech trees lose their leaves even later, and like the oaks, they too originated in the tropics. The last leaves don’t fall off until spring, when new buds push them.
The phenomenon did not go unnoticed. A man who made a deal with the Devil knew about it, and when he promised his soul in exchange for a favor, he told the Devil he could have the soul as soon as the oak trees were bare. The Devil agreed but was outsmarted, because the oaks are never bare. Always, a few leaves are clinging.
Insects and plants can leave you filled with wonder, but your questions can’t always be resolved. If a fungus wants what we want, if a tree wants what we want, and if insects want what we want, how much more obvious could it be that a vertebrate wants what we want? This brings us to the mouse and rat families. Plenty of them live in my house or in the woods and fields—voles, wood rats, and white-footed mice who are indigenous, also house mice who are not indigenous, originating as they did with brown rats in the lands that reach northward from Iraq to the shores of the Caspian Sea. They, with our cats and the bread we eat, represent a little ecosystem held over from the days when people domesticated grass. Eight thousand years ago, as the glaciers were receding from New Hampshire, Neolithic people between the Tigris and Euphrates rivers began to collect the seeds of the wild grasses that were to become wheat and millet. They stored the seeds in their granaries. The local rats and mice—the familiar creatures now known as brown rats and house mice—had been eating these seeds all along, and, glad to find them in large collections, also went into the granaries. Right behind them came their predator, Felis sylvestris lybica, the little tabby wildcat from whom domestic cats descend. In time, this closely tied group began to move to other places, wherever ships carried cargoes of grain. When grain was being loaded, some mice and rats might get on board with it, a few observant cats might follow, and away they would sail to populate the planet. Now the little ecosystem of wheat, mice, and cats, if not always rats, is part of almost every household in the so-called civilized world. It’s part of mine, and while these Near Eastern species may not be indigenous, they’re here now, and I value them. I too belong to an invasive species that began on the African savannah, the only primate ever to reach our part of the Holarctic, and when it occurs to me how foreign I am, surrounded on all sides by those who evolved here and are equipped to live outdoors year-round, I sometimes feel isolated.
But I needn’t—not if mice and rats are near, as these are our closest relatives in North America. We have the same ancestor. And although that ancestor lived during the Cretaceous, some of our similarities have firmly endured. That’s why mice are used in laboratory experiments as substitutes for human beings. That’s why the federal government has sponsored the “mouse knockout” project. Scientists are knocking out each of the twenty-thousand-odd genes in the mice genome one by one. Doing so will tell us a lot about the functions of our own twenty-thousand-odd genes, which closely match the mouse’s. And there’s really no surprise that we have genetic similarities. We have behavioral similarities too—strong ones. For instance
, we are successful breeders and have large populations. Also, unlike many species such as the deer, our families include adults of both genders. We also make sure we have supplies of food against the time when food might not be available. We are also good students, learning quickly and easily. As an animal trainer once put it, “You never have to tell a rat a thing twice.” Thus we can solve complex puzzles. We live in houses—rats and mice make their own homes if they don’t use ours. We have hands with which we manipulate objects and wash our faces and behind our ears. We don’t like to be controlled by others—we are happy if we manage our own lives, as was demonstrated by a white-footed mouse in a laboratory. A scientist wanted to know if this mouse’s species preferred the soft light of dawn and dusk to full sunlight. So the mouse was placed in a box with two dimmer switches, one inside for the mouse to use, and the other outside for the scientist. But the experiment didn’t work as planned, because the mouse didn’t care about the light—he cared that he was being manipulated. When the scientist turned up the lights, the mouse turned them down. When the scientist turned them down, the mouse turned them up. He quickly saw that something was purposely changing his environment and he wanted to take control. He must have felt as we do when a small child snaps a light switch off and on. It makes us crazy, and we immediately put a stop to it. Thus the unplanned result of the experiment was not surprising, and perhaps had its roots in the Cretaceous, where, like many other animals today, our ancestors must have valued their autonomy. The most surprising similarity we share with mice is that we sing, not just squeaks or howls, but actual music, and both our species do it well. The least surprising similarity is that we eat the same foods.
The Hidden Life of Deer Page 14
