The Best American Science and Nature Writing Part 6

Though modern genetics vindicates Darwin in all sorts of ways, it also turns the spotlight on his biggest mistake. Darwin's own ideas on the mechanism of inheritance were a messa"and wrong. He thought that an organism blended together a mixture of its parents' traits, and later in his life he began to believe it also pa.s.sed on traits acquired during its lifetime. He never understood, as the humble Moravian monk Gregor Mendel did, that an organism isn't a blend of its two parents at all, but the composite result of lots and lots of individual traits pa.s.sed down by its father and mother from their own parents and their grandparents before them.

Mendel's paper describing the particulate nature of inheritance was published in an obscure Moravian journal in 1866, just seven years after The Origin of Species. He sent it hopefully to some leading scientists of the day, but it was largely ignored. The monk's fate was to die years before the significance of his discovery was appreciated. But his legacy, like Darwin's, has never been more alive.

TIM FLANNERY The Superior Civilization.

FROM The New York Review of Books.

ANTS ARE SO MUCH A PART of our everyday lives that unless we discover them in our sugar bowl we rarely give them a second thought. Yet those minuscule bodies voyaging across the kitchen counter merit a closer look, for as the entomologists Bert Holldobler and Edward O. Wilson tell us in their latest book, they are part of a superorganism. Superorganisms such as some ant, bee, and termite colonies represent a level of organization intermediate between single organisms and the ecosystem: you can think of them as comprised of individuals whose coordination and integration have reached such a sophisticated level that they function with some of the seamlessness of a human body. The superorganism whose "hand" reaches into your sugar bowl is probably around the size of a large octopus or a garden shrub, and it will have positioned itself so that its vital parts are hidden and sheltered from climatic extremes while it still has easy access to food and water.

The term "superorganism" was first coined in 1928 by the great American ant expert William Morton Wheeler. Over the ensuing eighty years, as debates around sociobiology and genetics have altered our perspectives, the concept has fallen into and out of favor, and Holldobler and Wilson's book is a self-professed and convincing appeal for its revival. Five years in the making, The Superorganism draws on centuries of entomological research, charting much of what we know of the evolution, ecology, and social organization of the ants.

For all its inherent interest to an intelligent lay reader, it's a technical work filled with complex genetics, chemistry, and entomological jargon such as, for example, "gamergate," "eclosed," and "a.n.a.l trophallaxis." Occasional lapses add to the lay reader's difficulties. The etymology of "gamergate" ("married worker"), for example, which is so useful in understanding the term, is given only many pages after it's first introduced. I fear that The Superorganism may reach a smaller audience than it deserves, which is a great pity, for this is a profoundly important book with immediate relevance for anyone interested in the trends now shaping our own soci e ties.

Ants first evolved around 100 million years ago, and they have since diversified enormously. With 14,000 described species, and perhaps as many still awaiting discovery, they have colonized every habitable continent and almost every conceivable ecological niche. They vary enormously in size and shape. The smallest are the leptanilline ants, which are so rarely encountered that few entomologists have ever seen one outside of a museum. They are possibly the most primitive ants in existence, and despite being less than a millimeter in length they are formidable hunters. Packs of these Lilliputian creatures swarm through the gaps between soil particles in search of venomous centipedes much larger than themselves, which form their only prey. The largest ant in existence, in contrast, is the bullet ant, Dinoponera quadriceps (of which Holldobler and Wilson give abundant details, yet frustratingly neglect to inform us precisely how large these formidable-sounding creatures are). Inhabitants of the Neotropicsa"South and Central Americaa"bullet ants belong to a great group known as the ponerines.

In explaining what a superorganism is, Holldobler and Wilson draw up a useful set of "functional parallels" between an organism (such as ourselves) and the superorganism that is an ant colony. The individual ants, they say, function like cells in our body, an observation that's given more piquancy when we realize that, like many of our cells, individual ants are extremely short-lived. Depending upon the species, between 1 and 10 percent of the entire worker population of a colony dies each day, and in some species nearly half of the ants that forage outside the nest die daily. The specialized ant castesa"such as workers, soldiers, and queensa"correspond, they say, to our organs; and the queen ant, which in some instances never moves, but which can lay twenty eggs every minute for all of her decade-long life, is the equivalent of our gonads.

Pursuing the same reasoning, Holldobler and Wilson argue that the nests of some ants correspond to the skin and skeleton of other creatures. Some ant nests are so enormous that they are akin to the skeletons of whales. Those of one species of leafcutter ant from South America, for example, can contain nearly two thousand individual chambers, some with a capacity of fifty liters, and they can involve the excavation of forty tons of earth and extend over hundreds of square feet. Coordination within such giant colonies, which can house 8 million individual ants, occurs through ant communication systems that are extraordinarily sophisticated and are the equivalent of the human nervous system. Not all ant species have reached this level of organization. Indeed, one of the most successful groups of ants, the ponerines, rarely qualifies for superorganism status.

Parallels between the ants and ourselves are striking for the light they shed on the nature of everyday human experiences. Some ants get forced into low-status jobs and are prevented from becoming upwardly mobile by other members of the colony. Garbage dump workers, for example, are confined to their humble and dangerous task of removing rubbish from the nest by other ants who respond aggressively to the odors that linger on the garbage workers' bodies.

Some of the most fascinating insights into ants have come from researchers who measure the amount of carbon dioxide given off by colonies. This is rather like measuring the respiration rate in humans in that it gives an indication of the amount of work the superorganism is doing. The researchers discovered (perhaps un-surprisingly) that colonies experiencing internal conflict between individuals seeking to become reproductively dominant produce more CO2 than do tranquil colonies where the social order is long established. But extraordinarily, they also discovered that about three hours after removing a queen ant, the CO2 emissions from a colony drop. "Removing the queen thus has a clear effect on worker behavior, apparently reducing their inclination to work for the colony," the researchers concluded. While it's dangerous to anthropomorphize, it seems that ants may have their periods of mourning just as we humans do when a great leader pa.s.ses from us.

However, ants clearly are fundamentally different from us. A whimsical example concerns the work of ant morticians, which recognize ant corpses purely on the basis of the presence of a product of decomposition called oleic acid. When researchers daub live ants with the acid, the undertakers promptly carry off the acid-daubed ants to the ant cemetery, despite the fact that they are alive and kicking. Indeed, unless they clean themselves very thoroughly they are repeatedly dragged to the mortuary, despite showing every other sign of life.

The means that ants use to find their way in the world are fascinating. It has recently been found that ant explorers count their steps to determine where they are in relation to home. This remarkable ability was discovered by researchers who lengthened the legs of ants by attaching stilts to them. The stilt-walking ants, they observed, became lost on their way home to the nest at a distance proportionate to the length of their stilts.

The princ.i.p.al tools ants use, however, in guiding their movements and actions are potent chemical signals known as pheromones. So pervasive and sophisticated are pheromones in coordinating actions among ants that it's appropriate to think of ants as "speaking" to each other through pheromones. Around forty different pheromone-producing glands have been discovered in ants, and, although no single species has all forty glands, enough diversity of signaling is present to allow for the most sophisticated interactions. The fire ant, for example, uses just a few glands to produce its eighteen pheromone signals, yet this number, along with two visual signals, is sufficient to allow its large and sophisticated colonies to function.

Pheromone trails are laid by ants as they travel, and along well-used routes these trails take on the characteristics of a superhighway. From an ant's perspective, they are three-dimensional tunnels perhaps a centimeter wide that lead to food, a garbage dump, or home. If you wipe your finger across the trail of ants raiding your sugar bowl, you can demonstrate how important the pheromone trail is: as the ants reach the spot where your finger erased their trail they will become confused and turn back or wander. The chemicals used to mark such trails are extraordinarily potent. Just one milligram of the trail pheromone used by some species of attine ants to guide workers to leaf-cutting sites is enough to lay an ant superhighway sixty times around Earth.

Ant s.e.x seems utterly alien. Except for short periods just before the mating season, when an ant colony is reproducing, it is composed entirely of females, and among some primitive species virgin births are common. All the offspring of such virgin mothers, however, are winged males that almost invariably leave the nest. If a female ant mates, however, all of her fertilized eggs become females. In many ant societies, reproduction is the prerogative of a single individuala"the queen. She mates soon after leaving her natal colony and stores the sperm from that mating (or from multiple matings) all of her life, using it to fertilize (in some cases) millions of eggs over ten or more years.

Some ant species do not have queen ants in the strict sense. Instead, worker ants (which are all female) that have mated with a male ant become the dominant reproductive individuals. These are the gamergates, or "married workers," and their s.e.x life can be brutal. In one species the gamergates venture outside of the nest to attract a male, engage him in copulation, then carry him into the nest before snipping off his genitals and throwing away the rest of his body. The severed genitals continue to inseminate the gamergate for up to an hour, after which they too are discarded. The fertilized gamergates then vie for dominance, causing disruptive conflict in the nest. Sometimes an oligarchy of gamergates is established, but in other instances a single gamergate triumphs.

You might think that such an established gamergate would watch the colony carefully for signs of emerging rivals, but this is not the case. Instead it's the worker ants that do so by taking a keen interest in the s.e.xual status of their sisters. If they sense that one is becoming a s.e.xually active gamergate, they will turn on her, either a.s.saulting her or watching carefully until she produces eggs, which they promptly consume. It's intriguing that the sterile workers play the role of monitoring and regulating the s.e.xual life of the colony. In a stretch of the imagination, I can see parallels between this behavior and the role of policing and censuring the s.e.x lives of the rich and famous that gossip magazines play in our own society.

The ponerines are the most diverse of all the ant groups and are global in distribution. They cannot really be thought of as sophisticated superorganisms, however, for they tend to live in small colonies of a few tens to a few thousand individuals, with one Australian species living in colonies of just a dozen. Like Stone Age human hunters who specialized in killing woolly mammoths, the ponerines tend to specialize in hunting one or a few kinds of prey. That the great success of the ponerines is achieved despite their primitive social organization presents entomologists with what is known as the ponerine paradox. It lacks a widely accepted solution, but researchers suspect that it's the ponerines' predilection to seek specialized types of prey that limits their colony size (for such specialized hunters cannot gather enough food to develop large and sophisticated colonies). If this is the case, then the very characteristic that helps the ponerines to diversify and survive in a wide variety of environments also prevents them from attaining superorganism status.

The progress of ants from this relatively primitive state to the complexity of the most finely tuned superorganisms leaves no doubt that the progress of human evolution has largely followed a path taken by the ants tens of millions of years earlier. Beginning as simple hunter-gatherers, some ants have learned to herd and milk bugs, just as we milk cattle and sheep. There are ants that take slaves, ants that lay their eggs in the nests of foreign ants (much as cuckoos do among birds), leaving the upbringing of their young to others, and there are even ants that have discovered agriculture. These agricultural ants represent the highest level of ant civilization, yet it is not plants that they cultivate but mushrooms. These mushroom farmers are known as attines, and they are found only in the New World. Widely known as leafcutter ants, they are doubtless familiar from wildlife doc.u.mentaries.

The attines, say Holldobler and Wilson, are "Earth's ultimate superorganisms," and there is no doubt that their status is due to their agricultural economy, which they developed 50 to 60 million years before humans sowed the first seed. Indeed, it is in the changes wrought in attine societies by agriculture that the princ.i.p.al interest for the student of human societies lies. The most sophisticated of attine ant species has a single queen in a colony of millions of sterile workers that vary greatly in size and shape, the largest being two hundred times heavier than the smallest. Their system of worker specialization is so intricate that it recalls Swift's ditty on fleas: So, naturalists observe, a flea.

Has smaller fleas that on him prey;

And these have smaller still to bite 'em;

And so proceed ad infinitum.

In the case of the attines, however, the varying size cla.s.ses have specific jobs to do. Some cut a piece from a leaf and drop it to the ground, while others carry the leaf fragment to a depot. From there others carry it to the nest, where smaller ants cut it into fragments. Then ants that are smaller still take these pieces and crush and mold them into pellets, which even smaller ants plant out with strands of fungus. Finally, the very smallest ants, known as minims, weed and tend the growing fungus bed. These minute and dedicated gardeners do get an occasional outing, however, for they are known to walk to where the leaves are being cut and hitch a ride back to the nest on a leaf fragment. Their purpose in doing this is to protect the carrier ants from parasitic flies that would otherwise attack them. Clearly, not only did the attines beat us to agriculture, but they exemplified the concept of the division of labor long before Adam Smith stated it.

You may not believe it, but, like the sailors of old, the leafcutter ants "sing" as they work. Leaf-cutting is every bit as strenuous for the ants as hauling an anchor is for human beings, and their singing, which takes the form of stridulation (a sound created by the rubbing together of body parts), a.s.sists the ants in their work by imparting vibrations to the mandible that is cutting the leaf, enhancing its action in a manner akin to the way an electric knife helps us cut roasts. The leafcutters also use stridulation to cry for help, for example when workers are trapped in an underground cave-in. These cries for help soon prompt other ants to rush in and begin digging until they've reached their trapped sisters.

The fungus farmed by the leafcutter ants grows in underground chambers whose temperature, humidity, and acidity are precisely regulated to optimize its growth. The fungus, which produces a tiny mushroom, grows nowhere else, and genetic studies reveal that various attine ant species have been cultivating the same fungus strain for millions of years. In truth, after tens of millions of years of coevolution, such is their interdependence that the ants cannot live without the fungus nor the fungus without the ants. The system is not perfect, however, for the ants' fungal gardens are occasionally devastated by pests. One of the worst is an invasive fungus known as Escovopsis, whose depredations can become so severe that the leafcutters must desert their hard-won gardens and start elsewhere anew. Often a colony so beset evicts a smaller attine colony, taking over the premises and enlarging them to suit.

Fortunately, the ants possess a potent defense against this fungal weed that usually prevents its proliferation. Their fungicide is produced by a bacterium that is found only in pits located on specific parts of the ants' bodies and is known to exist nowhere else. These bacteria produce secretions that not only destroy the Escovopsis pest but promote the growth of the fungus the ants wish to cultivate. Thus these special bacteria must be considered as comprising the third element in a triumvirate of coevolved organisms, whose fate is now so closely interwoven that they are utterly interdependent and form a single, functional whole. Humanity's dependence upon a few grainsa"princ.i.p.ally wheat and ricea"and the complete dependence on cultivated varieties of these plants by human farmers presents a similar symbiosis.

One curious aspect of the agricultural enterprise of the attines is that the worker ants rarely eat the fungus they cultivate. Studies show that the adults gain most of their nutrition from plant sap, deriving a mere 5 percent from fungus. The balance of nutrients in the fungus, as it happens, is poorly suited to the needs of adult ants but is perfect for their growing young. The mushroom gardens are thus cultivated princ.i.p.ally for the delectation of the ant larvae. Indeed it forms their only source of food.

When growing fungus on such a large scale, waste management becomes a crucial issue, and the attines have developed a finely tuned solution. Their sanitation teams comprise one group of workers that gather the refuse from inside the colony and dump it at depots outside. From there dump managers that work exclusively outside the nest carry the waste to great disposal sites far from the colony. The dump managers that work outside are mostly older ants that have only a short time to live in any case, which is a good thing, for the great refuse dumps they toil at teem with pathogens and toxins. This system effectively quarantines the colony from a dangerous threat and at the same time minimizes loss of worker life. Curiously, humans have found a use for the ant refuse. So strong is the ants' aversion to it that South American farmers gather it and sprinkle it around young plants they wish to protect from attacks by leafcutters.

One can hardly help but admire the intelligence of the ant colony, yet theirs is an intelligence of a very particular kind. "Nothing in the brain of a worker ant represents a blueprint of the social order," Holldobler and Wilson tell us, and there is no overseer or "brain caste" that carries such a master plan in its head. Instead, the ants have discovered how to create strength from weakness by pooling their individually limited capacities into a collective decision-making system that bears an uncanny resemblance to our own democratic processes.

This capacity is perhaps most clearly ill.u.s.trated when an ant colony finds reason to move. Many ants live in cavities in trees or rocks, and the size, temperature, humidity, and precise form and location of the chamber are all critically important to the success of the superorganism. Individual ants appear to size up the suitability of a new cavity using a rule of thumb called Buffon's needle algorithm. Each one does this by laying a pheromone trail across the cavity that is unique to that individual ant, then walking about the s.p.a.ce for a given period of time. The more often they cross their own trail, the smaller the cavity is.

This yields only a rough measure of the cavity's size, for some ants using it may choose cavities that are too large, and others will choose cavities that are too small. The cavity deemed most suitable by the majority, however, is likely to be the best. The means employed by the ants to "count votes" for and against a new cavity is the essence of elegance and simplicity, for the cavity visited by the most ants has the strongest pheromone trail leading to it, and it is in following this trail that the superorganism makes its collective decision. The band of sisters thus sets off with a unity of purpose, dragging their gargantuan queen and all their eggs and young to a new home that gives them the greatest chance of a comfortable and successful life.

Reflecting on our own societies when armed with knowledge of the ants as provided in The Superorganism, it's hard to avoid the conclusion that we are in the process of metamorphosing into the largest, most formidable superorganism of all time. Yet even the creation of a superorganism on this colossal scale is not entirely new, for just thirty years ago another gargantuan superorganism came into existence, and it was the ants that created it. This superorgan ism is composed of fire ants, and already it covers most of the southern United States. It consists of billions of individuals whose ancestors were accidentally imported from South America to Mobile, Alabama, in the 1930s.

In their native land fire ants form discrete colonies, with just one or a few queen ants at the center of each. This is how most ants live, but something very strange happened to the fire ants soon after they reached the United States. They gave up founding colonies by the traditional method of sending off flights of virgin queens, and instead began producing many small queens, which spread the colony rather in the way an amoeba spreads, by establis.h.i.+ng extensions of the original body. Astonis.h.i.+ngly, at the same time the ants ceased to defend colony boundaries against other fire ants. As Holldobler and Wilson put it, "With territorial boundaries erased, local populations now coalesce into a single sheet of intercompatible ants spread across the inhabited landscape." This remarkable s.h.i.+ft was caused by a change in the frequency of a single gene.

Is it possible, The Superorganism left me wondering, that the invention of the Internet is leading to a similar social evolution of our own species? The proliferation of conflict, much of it prompted by defense of national boundaries, may make us doubt it, but other trends are occurring that give pause for thought. As we strive to avert a global economic disaster or agree on a global treaty to prevent catastrophic climate change, we inevitably build structures that, as with the ants, allow the superorganism to function more efficiently. But of course it's possible that we'll fail to make the gradea"that our destructive path will catch up with us before we can make the transition to a seamlessly working superorganism.

When conferring an honorary degree upon the man who invented the term "superorganism," President Lowell of Harvard University said of William Morton Wheeler that he had demonstrated how ants "like human beings can create civilizations without the use of reason." Create perhaps, but there is no question of maintaining this first global civilization without resort to humanity's defining faculty. As the twenty-first century progresses we'll doubtless find ourselves trying to shape our planet-sized nest as carefully as an ant colony does, but the great difference is this: in the case of the human superorganism it will be our intelligence that will guide us. We have to hope that we shall find ourselves living sustainably in a global superorganism whose own self-created intelligence has been bent to the management and the maintenance of its life systems for the greater good of life as a whole.

KENNETH BROWER Still Blue.

FROM National Geographic.

IN ACAPULCO HARBOR, amid the white yachts, R.V. Pacific Storm stood out: a working boat, black hulled, a West Coast trawler in a previous life, reborn now as a research vessel. There were bigger, more opulent boats in the harbora"fortunes are invested in the white yachts of Acapulcoa"but this eighty-five-foot trawler, with its grim mien and high black bow, was the s.h.i.+p for me. Asked to choose, from all this fleet, the vessel to carry me on a month-long cruise in pursuit of blue whales, I would not have hesitated. As Flip Nicklin and I pa.s.sed our gear up the trawler's ladder and stowed it in our cabin, I felt an almost savage contentment.

Call me Ishmael, if you like, but whenever I find myself growing grim about the mouth; whenever it is a damp, drizzly November in my soul; whenever I have spent too many consecutive months at the computer keyboard, in artificial light, like some sort of troglodyte, self-imprisoned, pecking out my living, I account it high time to get to sea as soon as I can. I jumped at the a.s.signment on Pacific Storm. As the voyage was to depart on the third of January, I made three New Year's resolutions: I would try to be an affable s.h.i.+pmate. I would strip all the blubber from my prose. I would refrain from making a single allusion to Herman Melville.

Did I mention we were after a white whale?

It's true. In the eastern North Pacific population of blue whalesa"the group that summers mostly off California and whose migration we were following southa"there is a white blue whale, maybe an albino. An inflatable skiff from Pacific Storm had satellite-tagged this whale off Santa Barbara four months before, but his tag, num ber 4172, had ceased transmitting a few weeks after implantation, and now his whereabouts were a mystery. The sun-synchronous, polar-orbiting TIROS N satellites could no longer track him, but he was one of the animals we hoped to see off Central America.

When we had settled in on Pacific Storm, Nicklin, cross-legged on his bunk, set up his Nikon D200 with its Sea & Sea underwater dome. He squeezed a dab of silicone grease from a small tube onto his fingertip and ran it around the rim of the dome's blue O-ring. He opened the back of the camera and gave a similar treatment to the O-ring at the stern. Nicklin is a new kind of whaler. His job is not to render the oil but to capture the essence of cetaceans, and the Nikon is his favorite harpoon.

Pacific Storm put to sea. We sailed a leg due south to avoid the Tehuantepec winds along the eastward bend of Central America, then turned southwest toward the temperature anomaly that was our destination.

The Costa Rica Dome is an upwelling of cold, nutrient-rich water generated by a meeting of winds and currents west of Central America. The location is not fixed; it meanders a bit, but the dome is reliably encountered somewhere between three hundred and five hundred miles offsh.o.r.e. The upwelling brings the thermoclinea"the boundary layer between deep, cold water and the warm water of the surfacea"up as high as thirty feet from the top. Upwelling with the cold, oxygen-poor water from the depths come nitrate, phosphate, silicate, and other nutrients. This manna, or antimannaa"a gift not from heaven but from the deepa"makes for an oasis in the sea. The upwelling nutrients of the dome fertilize the tiny plants of the phytoplankton, which feed the tiny animals of the zooplankton, which bring bigger animals, some of which are very big indeed.

The blue whale, Balaenoptera musculus, is the largest creature ever to live. Linnaeus derived the genus name from the Latin balaena, "whale," and the Greek pteron, "fin" or "wing." His species name, musculus, is the diminutive of the Latin mus, "mouse"a"apparently a Linnaean joke. The "little mouse whale" can grow to 200 tons and 100 feet long. A single little mouse whale weighs as much as the entire National Football League. Just as an elephant might pick up a little mouse in its trunk, so the elephant, in its turn, might be taken up by a blue whale and carried along on the colossal tongue. Had Jonah been injected intravenously, instead of swallowed, he could have swum the arterial vessels of this whale, boosted along every ten seconds or so by the slow, G.o.dlike pulse.

The great swimming speed of the blue whale, together with the remoteness of its strongholda"where three of Earth's oceans merge in the ice-cold waters around Antarcticaa"protected most of the species until early in the twentieth century. With the invention of explosive harpoons and fast, steam-powered catcher boats, the stronghold was breached. Through the first six decades of the twentieth century, 360,000 blue whales were killed. The population around South Georgia Island was extirpated, along with those that once fed in the coastal waters of j.a.pan. Some blue whale populations were reduced by ninety-nine one-hundredths, and the species tipped at the very brink of extinction.

For Bruce Mate and John Calambokidis, the head scientists aboard Pacific Storm, the irony is deep and poignant. The blue whales they study, the two thousand animals that summer off western North America, once just a splinter group, now make up a significant population.

Mate, director of the Marine Mammal Inst.i.tute at Oregon State University, is the world's most inventive and prolific satellite-tagger of whales. The dome first caught his attention in 1995, when a blue whale he had tagged off California in summer began transmitting off Costa Rica in winter. Calambokidis, a cofounder of Cascadia Research, in Olympia, Was.h.i.+ngton, is the West Coast's most prolific photo-identifier of whales. A tall, lean biologist with a Quaker seaman's beard and a monomaniacal dedication to bringing back diagnostic images, Calambokidis was tantalized by the reports from the satellite. In 1999 he made a reconnaissance of the dome by sailboat. The voyage was plagued by bad weather, and the sailboat was too small for its mission, yet at the dome Calambokidis managed to photo-identify ten whales that he had photographed off California.

Why would a blue whale depart from its feeding grounds at the end of summer and migrate thousands of miles to spend winter in this tropical zone of upwelling? Mate and Calambokidis thought they knew. The satellite data showed that some of the tagged whales lingered five months or more at the dome, arriving early in the southern migration and departing latea"a pattern that, in other species of baleen whales, is seen in pregnant females and new mothers. It had never been noted in blue whales, for the best of reasons: no one has ever witnessed the birth of a blue whale.

Gray, humpback, and right whalesa"the baleen species that have been studied at their calving groundsa"seem to feed little, if at all, at those grounds. But there is evidence that the blue whale might be different. Given its great size and enormous energy requirements, the blue whale may be forced to find winter grounds where it can do more than snack. The oasis of the Costa Rica Dome would satisfy this requirement. Plus, the productivity of the upwelling would help nursing mothers convert schools of krill into the barrels of milk required by the calves to put on their two hundred pounds a day.

Balaenoptera musculus received international protection in the mid-1960s, yet, for reasons not fully understood, it has scarcely rebounded. If the greatest of creatures is to come back, Mate and Calambokidis believe, its demographics and its movements need to be charted. The largest remaining population of the species is most vulnerable in tropical waters where it gives birth to dainty, twenty-five-foot-long, three-ton calves.

As we followed the corridor of the blue whale migration southward, we took turns standing whale watch on the bridge, searching the horizon for blows. Whales 5801 and 23043 had already arrived at the dome, according to the satellite, and number 5670 was nearing it. The scientists were particularly interested in 23043, because they knew the s.e.x, female, and because she had arrived at the dome early, as one might expect of a mother-to-be. The white blue whale, 4172, if he was migrating to the dome this year, was out there somewhere in the host moving south. The Pacific is a big ocean, however, and we saw not a single spout.

Now and again, day and night, the s.h.i.+p s.h.i.+fted to neutral, and the researchers put gear overboard: a CTD sensor, an echo sounder, and a hydrophone. The CTD sensor recorded conductivity (a measure of salinity), temperature, and depth. The echo sounder searched for concentrations of krill, upon which the blue whale subsists almost entirely. "We're doing some control observation on the way down," Mate explained. "If there's no krill, will the whales pa.s.s through? If there are big concentrations of krill, will they hang around? We're looking for p.o.o.p. We'll try to scoop it up, see if they're feeding. And checking their breath, which is fouler when they've eaten. I don't find blue whale breath offensivea"certainly not in comparison to gray whale breath, which is really foula"but blue whale breath can be strong."

The hydrophone was to detect blue whale voices. The simple song of the blue whale bulla"the thumping, stentorian, ba.s.so pro-fundo pulse of the A call, followed by the continuous tone of the B calla"is the mightiest song in the sea, theoretically capable of propagating halfway across an ocean basin. But big baleen whales often run silent. Except for a few dubious s.n.a.t.c.hes of song, we heard nothing at all.

When we reached the Costa Rica Dome, three days out of Acapulco, the ocean looked no different, just blue horizon and marching swells. It took a sounding by the CTD sensor to detect the thermocline lying just sixty feet under the surface. We had arrived. "Blow at eleven o'clock!" Calambokidis called down the next morning from the crosstrees, our crow's-nest, over his walkie-talkie. We saw two more blows side by side in quick successiona"our first blue whalesa"and we launched the tagging boats, beginning the repet.i.tive ritual that would occupy us for the next three weeks.

The boats were Coast Guard surplus, a pair of diesel-powered RHIBs, or rigid-hull inflatable boats. Sticking with meteorological nomenclature, we called the big one Hurricane and the small one Squall. I generally went out on Hurricane. Its commander was Bruce Mate. The second mate, and also the second Mate, was Mary Lou, the expedition videographer and the professor's wife of forty years. I was the biopsy guy. My first job was to c.o.c.k my crossbow, take a biopsy bolt from the cooler that served as ammunition box, nock the bolt, and then remove the sheath of aluminum foil protecting the tip from contamination by extraneous DNA. The bolt, when shot into the whale, would excise a plug of skin and blubber. About three inches back from its tip, the bolt was blocked by an oblong ball of yellow rubber that prevented the projectile from going in too deep and also served to bounce it off the whale.

Mounted on the rubber bow of Hurricane was a metal bowsprit, the "pulpit," custom-made for this work. Each time we closed on whales, I would follow Professor Mate up onto the narrow grate of the pulpit deck. From its holster, which was a transparent plastic tube lashed to the pulpit rail, Mate withdrew the satellite-tag "ap plicator," a long-barreled, red-metal blunderbuss with a wooden rifle stock. This device, originally a Norwegian invention for shooting line between s.h.i.+ps, is powered by compressed air from a scuba tank. The pop is adjustable. For blue whales, Mate sets the dial at 85 pounds per square inch of pressure. For sperm whales, which have very tough skin, he sets the pressure at 120 pounds. Both Mate and I wore waist harnesses, which we clipped into slings on the pulpit rail, freeing up our hands for the shooting.

The first we saw of a whale was almost always its blow.

When the sun was behind us, we sometimes saw a prismatic scatter of color in the explosive expansion of spray and vapora"a few milliseconds of rainbowa"before the color s.h.i.+mmered out and the spout faded to white.

Whenever a blue whale surfaced to blow nearby, I was struck by the blowholea"a pair of nostrils countersunk atop the tapering mound of the splash guard, built up almost into a kind of nose on the back of the head. Other baleen whales have splash guards too, but not like this. This nose was almost Roman. It seemed disproportionately large, even for the biggest of whales. Its size explained that loud, concussive exhalationa"less a breath than a detonationa"and its size explained the thirty-foot spout. It was a mighty blow, followed quickly by a mighty inhalation.

The second thing we saw of the whale was its back.

The blue whale is "a light bluish gray overall, mottled with gray or grayish white," as one field guide describes it, and the back is often, indeed, this advertised color, but just as often, depending on the light, the back shows as silvery gray or pale tan. Whichever the color, the back always has a gla.s.sy s.h.i.+ne. When you are close, you see the water sluicing off the vast back, first in rivulets and sheets, and then in a film that flows in lovely, pulsed patterns downhill to the sea.

If blue whales above water are only putatively blue, then below the surface they go indisputably turquoise. Balaenoptera musculus is a pale whale, and when seen through the blue filter of the ocean, its pallor goes turquoise or aquamarine. This view of the whale, downward through twenty to fifty feet of water, is for me the most haunting and evocative.

If the most beautiful hue of the blue whale is turquoise, then the most beautiful form, the finest sculpture, is in the flukes. In the first week of our tagging efforts, the tail always seemed to be wav ing goodbye. "Ta-ta," it signaled. "Nice try. Better luck next time." When a whale showed its flukesa"when the two palmate blades poised high in the aira"we would break off the chase, because elevated flukes meant a deep dive.

But sometimes we saw the flukes close under the surface. They were huge, wider than the boat, and in motion they were hypnotically lovely. "In no living thing are the lines of beauty more exquisitely defined than in the crescentic borders of these flukes," Melville writes in Moby d.i.c.k.

The last thing we saw of the whale was its "flukeprint."

When a whale or dolphin swims at shallow depths, turbulence from its flukes rises to form a circular slick on the surface: the footprint or flukeprint. The flukeprints of blue whales are large and surprisingly persistent. The smooth patch lingers long after the whale is gone. "It's a measure of how much energy is in the stroke," Mate told me one afternoon when he caught me staring at one of these slicks. The circle of the flukeprint is perfectly smooth, except for a few faint curves that mark the continued upwelling of energy. Eventually the chop of the ocean begins to erode the slick from the outside inward, but only slowly.

The emphatic flukeprint was another of those discouraging signs that caused us to call off a chase. "Holy smokes!" Mate said one afternoon, as we motored into the middle of a huge one. Ladd Irvine, a research a.s.sistant who served as helmsman, laughed in admiration: "We're not going to see him again for a while."

Out on the pulpit, the professor spread his feet for balance, rested the b.u.t.t of his applicator on the grating of the pulpit deck, and gripped the barrel just below the muzzle-loaded, chiseled tip of his satellite tag. His quick-dry khaki pants luffed and billowed in the sea wind, and now and again the breeze brought a powerful smell of staleness and mold, mixed sometimes with an alarming flatulence. Whew, Bruce! I thought on more than one occasion. Then one day, as the wind rippled in his khakis and we closed in on the spout ahead, the professor emitted a blast so powerful, inhuman, and malodorous that I realized he had to be completely innocent. What I had been smelling, all along, was not our leader. I had been smelling the bad breath of blue whales.

For almost a week at the dome, every whale slipped away from us. On our sixth day our luck changed. We saw three spouts to the southeast that morning and launched Hurricane.

The first two whales toyed with us, as usual, allowing us close, then pulling away. The third allowed us to get in perfect position. We paced the great turquoise shape, keeping abreast of the flukes as the whale coursed along underwater to starboard. As the animal surfaced to blow, it angled up from turquoise abstraction into photo-realism. Irvine gunned the engine. Up in the pulpit I clicked off my crossbow's safety. Mate tucked the rifle stock of the tag applicator into his shoulder, leaned outward over the pulpit rail, and aimed the long, red barrel almost straight downward at the rising whale, now just ten feet underwater. The whale blew, and the glistening wall of its flank erupted in a steep curve above the sea.

My instructions as biopsy guy were to wait for the bang of the tag applicator before firing my crossbow. The smooth flank of the whale filled my whole field of view; there was no way I could miss. At the bang of the applicator, I pulled my trigger. The bolt left the crossbow, and a black hole, small but inky, appeared where I had been aiming. It took a millisecond for me to understand that I was responsible for it, and I felt a pang of regret and guilt. I did that? I thought, like a boy whose pop fly has gone through a stained-gla.s.s window.

Then my sense of proportion returned. In relation to the vastness of this whale, my hole was just a mosquito bite. This was not a crime; it was a blow for science. On the pulpit, Mate and I un-clipped our harnesses and shook hands.

The blue whale writes a kind of longhand on the surface of the sea. There is the ovoid slick that forms above the head the moment before emergence, the long, narrow slick left by the arching back, and the circular slick of the flukeprint. There are the sputtering white fountains that a blue whale raises by blowing early, still gliding under the surfacea"a sequence of premature spouts. There are bubble blasts. I saw my first of these just ahead of the bowsprit, about twelve feet deep, as the blowhole of a whale erupted a big bolus of bubbles. It expanded toward the surface, vitreous and glittery, like a crystal chandelier falling upward. "Bubble blast," observed Mate.

This particular bubble blast seemed to be commentary directed at our persistent and irritating little boata"some kind of whale expletive, probably. It rose above the whale's head like a speech bal loon in a Gary Larson cartoon. Its message was something like "@*#&%$!?!"

Of all the marks of blue whale cursive, the most colorful was the defecation trail. The first defecation we saw was in a yearling, a little fifty-footer. This whale blew forty yards away, and behind it the ocean brightened in a long, red-orange contrail. "We have a defecation," Irvine announced. This contrail, a brick red streak of processed krill, more watery than particulate, was our first direct evidence that blue whales were feeding in winter at the Costa Rica Dome. As this was one of the hypotheses this expedition had been launched to test, Mate scrambled to find a Ziploc bag to collect a sample.

The evidence for feeding that we observed firsthand in the defecation trails was corroborated in the s.h.i.+p's laboratory. On her computer screen, Robyn Matteson, Mate's graduate student, monitored the echo sounder and the concentrations of krill it detected at the dome. Krill distribution was patchier than anyone had imagined, but dense schools of the small crustaceans were plainly here. Across the lab table, at their own computers, Calambokidis and Erin Oleson of Scripps Inst.i.tution of Oceanography studied the dive profiles recorded by acoustic tags they had succeeded in applying to several whales. The acoustic tags, deployed by pole and attached by suction cups, stay on the whale for hours, not months, like the more invasive satellite tags. Here at the dome, the depth recorders on the tags showed dives to eight hundred feet and deeper. The vertical line marking each dive, on reaching its greatest depth, began to zigzag in the sawtooth pattern characteristic of blue whales when lunge-feeding on krill.

The evidence for calving at the Costa Rica Dome proved more elusive, but after many fruitless days, it arrived finally, to starboard, by way of a mother and her calf.

The pair were moving slowly, spending a lot of time at the surface. The mother surprised us by allowing her calf to turn toward Pacific Storm. A mother whale often interposes herself between her calf and potential danger, but this mother was an easygoing, Montessori sort of parent, and she let her baby explore.

John Calambokidis drove Squall out to snap surface pictures for photo identification. Nicklin and cameraman Ernie Kovacs grabbed their gear and went along. On nearing the whales, they pulled on their fins and slipped overboard. At first they saw nothing through their dive masks but blue. Then Kovacs, looking for the youngster, was startled to see it pa.s.s, maybe five feet below his fins. This whale was just a baby, yet its blue back seemed to pa.s.s under him endlessly. The calf, gliding by Nicklin, rolled slightly to bring an eye to bear on him. It peered into the gla.s.s...o...b..of the camera housing, and Nicklin's shutter winked back.

After twenty-one days at the Costa Rica Dome, we could stay no longer and turned north for Acapulco.

On the voyage home, we took stock. There had been disappointments: we wished we had satellite-tagged more whales, had seen more calves, had experienced more underwater encounters with blue whales. We were sorry not to have glimpsed whale 4172, the white bull. But for the most part we were satisfied.

In three weeks spent crisscrossing the dome, we had succeeded in finding three whales satellite-tagged in California and tracked down here. Each time we homed in on the transmissions of one of these telemetric whales, we had found it in the company of "clean" whales. Satellite-tagging had proved itself an efficient method for locating concentrations of the untagged. We had satellite-tagged three new blue whales (but one tag failed to transmit), affixed acoustic tags to six more, and photo-identified about seventy. Thirteen of those seventy were from California. The voyage proved that the dome is visited by large numbers of blue whales. We saw many threesomes, the romantic triangles of the blue whale, and we witnessed much boisterous courts.h.i.+p behavior, all suggesting that the dome is a mating ground. We demonstrated beyond a doubt that blue whales do feed here in the winter. With son.o.buoys and acoustic tags, we eavesdropped on A and B calls of the blue whale song and on the D calls whales make between bouts of feeding, and thus began notation of the winter music in this patch of ocean.

The news from the dome is good.

The grandest creature in all creation has been hunted by our kind, the thinking ape, to near extinction. Its numbers still are low, but it was hard not to feel optimistic. In my bunk with Nicklin's laptop, lingering over his digital portraits of the curious calf, I thought I could read, in its strange visage, a gargantuan impishness. I found this cheering. The young do give us hope.