CHAPTER 23: THE RICHNESS OF BEING

HERE AND THERE in the Natural History Museum in London, built into recesses along the underlit corridors or standing between glass cases of minerals and ostrich eggs and a century or so of other productive clutter, are secret doors—at least secret in the sense that there is nothing about them to attract the visitor’s notice. Occasionally you might see someone with the distracted manner and interestingly willful hair that mark the scholar emerge from one of the doors and hasten down a corridor, probably to disappear through another door a little further on, but this is a relatively rare event. For the most part the doors stay shut, giving no hint that beyond them exists another—a parallel—Natural History Museum as vast as, and in many ways more wonderful than, the one the public knows and adores.

The Natural History Museum contains some seventy million objects from every realm of life and every corner of the planet, with another hundred thousand or so added to the collection each year, but it is really only behind the scenes that you get a sense of what a treasure house this is. In cupboards and cabinets and long rooms full of close-packed shelves are kept tens of thousands of pickled animals in bottles, millions of insects pinned to squares of card, drawers of shiny mollusks, bones of dinosaurs, skulls of early humans, endless folders of neatly pressed plants. It is a little like wandering through Darwin’s brain. The spirit room alone holds fifteen miles of shelving containing jar upon jar of animals preserved in methylated spirit.

Back here are specimens collected by Joseph Banks in Australia, Alexander von Humboldt in Amazonia, Darwin on theBeagle voyage, and much else that is either very rare or historically important or both. Many people would love to get their hands on these things. A few actually have. In 1954 the museum acquired an outstanding ornithological collection from the estate of a devoted collector named Richard Meinertzhagen, author ofBirds of Arabia , among other scholarly works. Meinertzhagen had been a faithful attendee of the museum for years, coming almost daily to take notes for the production of his books and monographs. When the crates arrived, the curators excitedly jimmied them open to see what they had been left and were surprised, to put it mildly, to discover that a very large number of specimens bore the museum’s own labels. Mr. Meinertzhagen, it turned out, had been helping himself to their collections for years. It also explained his habit of wearing a large overcoat even during warm weather.

A few years later a charming old regular in the mollusks department—“quite a distinguished gentleman,” I was told—was caught inserting valued seashells into the hollow legs of his Zimmer frame.

“I don’t suppose there’s anything in here that somebody somewhere doesn’t covet,” Richard Fortey said with a thoughtful air as he gave me a tour of the beguiling world that is the behind-the-scenes part of the museum. We wandered through a confusion of departments where people sat at large tables doing intent, investigative things with arthropods and palm fronds and boxes of yellowed bones. Everywhere there was an air of unhurried thoroughness, of people being engaged in a gigantic endeavor that could never be completed and mustn’t be rushed. In 1967, I had read, the museum issued its report on the John Murray Expedition, an Indian Ocean survey, forty-four years after the expedition had concluded. This is a world where things move at their own pace, including a tiny lift Fortey and I shared with a scholarly looking elderly man with whom Fortey chatted genially and familiarly as we proceeded upwards at about the rate that sediments are laid down.

When the man departed, Fortey said to me: “That was a very nice chap named Norman who’s spent forty-two years studying one species of plant, St. John’s wort. He retired in 1989, but he still comes in every week.”

“How do you spend forty-two years on one species of plant?” I asked.

“It’s remarkable, isn’t it?” Fortey agreed. He thought for a moment. “He’s very thorough apparently.” The lift door opened to reveal a bricked-over opening. Fortey looked confounded. “That’s very strange,” he said. “That used to be Botany back there.” He punched a button for another floor, and we found our way at length to Botany by means of back staircases and discreet trespass through yet more departments where investigators toiled lovingly over once-living objects. And so it was that I was introduced to Len Ellis and the quiet world of bryophytes—mosses to the rest of us.

When Emerson poetically noted that mosses favor the north sides of trees (“The moss upon the forest bark, was pole-star when the night was dark”) he really meant lichens, for in the nineteenth century mosses and lichens weren’t distinguished. True mosses aren’t actually fussy about where they grow, so they are no good as natural compasses. In fact, mosses aren’t actually much good for anything. “Perhaps no great group of plants has so few uses, commercial or economic, as the mosses,” wrote Henry S. Conard, perhaps just a touch sadly, inHow to Know the Mosses and Liverworts , published in 1956 and still to be found on many library shelves as almost the only attempt to popularize the subject.

They are, however, prolific. Even with lichens removed, bryophytes is a busy realm, with over ten thousand species contained within some seven hundred genera. The plump and statelyMoss Flora of Britain and Ireland by A. J. E. Smith runs to seven hundred pages, and Britain and Ireland are by no means outstandingly mossy places. “The tropics are where you find the variety,” Len Ellis told me. A quiet, spare man, he has been at the Natural History Museum for twenty-seven years and curator of the department since 1990. “You can go out into a place like the rain forests of Malaysia and find new varieties with relative ease. I did that myself not long ago. I looked down and there was a species that had never been recorded.”

“So we don’t know how many species are still to be discovered?”

“Oh, no. No idea.”

You might not think there would be that many people in the world prepared to devote lifetimes to the study of something so inescapably low key, but in fact moss people number in the hundreds and they feel very strongly about their subject. “Oh, yes,” Ellis told me, “the meetings can get very lively at times.”

I asked him for an example of controversy.

“Well, here’s one inflicted on us by one of your countrymen,” he said, smiling lightly, and opened a hefty reference work containing illustrations of mosses whose most notable characteristic to the uninstructed eye was their uncanny similarity one to another. “That,” he said, tapping a moss, “used to be one genus,Drepanocladus . Now it’s been reorganized into three:Drepanocladus, Wamstorfia, andHamatacoulis .”

“And did that lead to blows?” I asked perhaps a touch hopefully.

“Well, it made sense. It made perfect sense. But it meant a lot of reordering of collections and it put all the books out of date for a time, so there was a bit of, you know, grumbling.”

Mosses offer mysteries as well, he told me. One famous case—famous to moss people anyway—involved a retiring type calledHyophila stanfordensis , which was discovered on the campus of Stanford University in California and later also found growing beside a path in Cornwall, on the southwest tip of England, but has never been encountered anywhere in between. How it came to exist in two such unconnected locations is anybody’s guess. “It’s now known asHennediella stanfordensis ,” Ellis said. “Another revision.”

We nodded thoughtfully.

When a new moss is found it must be compared with all other mosses to make sure that it hasn’t been recorded already. Then a formal description must be written and illustrations prepared and the result published in a respectable journal. The whole process seldom takes less than six months. The twentieth century was not a great age for moss taxonomy. Much of the century’s work was devoted to untangling the confusions and duplications left behind by the nineteenth century.

That was the golden age of moss collecting. (You may recall that Charles Lyell’s father was a great moss man.) One aptly named Englishman, George Hunt, hunted British mosses so assiduously that he probably contributed to the extinction of several species. But it is thanks to such efforts that Len Ellis’s collection is one of the world’s most comprehensive. All 780,000 of his specimens are pressed into large folded sheets of heavy paper, some very old and covered with spidery Victorian script. Some, for all we knew, might have been in the hand of Robert Brown, the great Victorian botanist, unveiler of Brownian motion and the nucleus of cells, who founded and ran the museum’s botany department for its first thirty-one years until his death in 1858. All the specimens are kept in lustrous old mahogany cabinets so strikingly fine that I remarked upon them.

“Oh, those were Sir Joseph Banks’s, from his house in Soho Square,” Ellis said casually, as if identifying a recent purchase from Ikea. “He had them built to hold his specimens from theEndeavour voyage.” He regarded the cabinets thoughtfully, as if for the first time in a long while. “I don’t know howweended up with them in bryology,” he added.

This was an amazing disclosure. Joseph Banks was England’s greatest botanist, and theEndeavour voyage—that is the one on which Captain Cook charted the 1769 transit of Venus and claimed Australia for the crown, among rather a lot else—was the greatest botanical expedition in history. Banks paid £10,000, about $1 million in today’s money, to bring himself and a party of nine others—a naturalist, a secretary, three artists, and four servants—on the three-year adventure around the world. Goodness knows what the bluff Captain Cook made of such a velvety and pampered assemblage, but he seems to have liked Banks well enough and could not but admire his talents in botany—a feeling shared by posterity.

Never before or since has a botanical party enjoyed greater triumphs. Partly it was because the voyage took in so many new or little-known places—Tierra del Fuego, Tahiti, New Zealand, Australia, New Guinea—but mostly it was because Banks was such an astute and inventive collector. Even when unable to go ashore at Rio de Janeiro because of a quarantine, he sifted through a bale of fodder sent for the ship’s livestock and made new discoveries. Nothing, it seems, escaped his notice. Altogether he brought back thirty thousand plant specimens, including fourteen hundred not seen before—enough to increase by about a quarter the number of known plants in the world.

But Banks’s grand cache was only part of the total haul in what was an almost absurdly acquisitive age. Plant collecting in the eighteenth century became a kind of international mania. Glory and wealth alike awaited those who could find new species, and botanists and adventurers went to the most incredible lengths to satisfy the world’s craving for horticultural novelty. Thomas Nuttall, the man who named the wisteria after Caspar Wistar, came to America as an uneducated printer but discovered a passion for plants and walked halfway across the country and back again, collecting hundreds of growing things never seen before. John Fraser, for whom is named the Fraser fir, spent years in the wilderness collecting on behalf of Catherine the Great and emerged at length to find that Russia had a new czar who thought he was mad and refused to honor his contract. Fraser took everything to Chelsea, where he opened a nursery and made a handsome living selling rhododendrons, azaleas, magnolias, Virginia creepers, asters, and other colonial exotica to a delighted English gentry.

Huge sums could be made with the right finds. John Lyon, an amateur botanist, spent two hard and dangerous years collecting specimens, but cleared almost $200,000 in today’s money for his efforts. Many, however, just did it for the love of botany. Nuttall gave most of what he found to the Liverpool Botanic Gardens. Eventually he became director of Harvard’s Botanic Garden and author of the encyclopedicGenera of North American Plants(which he not only wrote but also largely typeset).

And that was just plants. There was also all the fauna of the new worlds—kangaroos, kiwis, raccoons, bobcats, mosquitoes, and other curious forms beyond imagining. The volume of life on Earth was seemingly infinite, as Jonathan Swift noted in some famous lines:

So, naturalists observe, a flea

Hath smaller fleas that on him prey;

And these have smaller still to bite ’em;

And so proceed ad infinitum.

All this new information needed to be filed, ordered, and compared with what was known. The world was desperate for a workable system of classification. Fortunately there was a man in Sweden who stood ready to provide it.

His name was Carl Linné (later changed, with permission, to the more aristocraticvonLinné), but he is remembered now by the Latinized form Carolus Linnaeus. He was born in 1707 in the village of Råshult in southern Sweden, the son of a poor but ambitious Lutheran curate, and was such a sluggish student that his exasperated father apprenticed him (or, by some accounts, nearly apprenticed him) to a cobbler. Appalled at the prospect of spending a lifetime banging tacks into leather, young Linné begged for another chance, which was granted, and he never thereafter wavered from academic distinction. He studied medicine in Sweden and Holland, though his passion became the natural world. In the early 1730s, still in his twenties, he began to produce catalogues of the world’s plant and animal species, using a system of his own devising, and gradually his fame grew.

Rarely has a man been more comfortable with his own greatness. He spent much of his leisure time penning long and flattering portraits of himself, declaring that there had never “been a greater botanist or zoologist,” and that his system of classification was “the greatest achievement in the realm of science.” Modestly he suggested that his gravestone should bear the inscriptionPrinceps Botanicorum , “Prince of Botanists.” It was never wise to question his generous self-assessments. Those who did so were apt to find they had weeds named after them.

Linnaeus’s other striking quality was an abiding—at times, one might say, a feverish—preoccupation with sex. He was particularly struck by the similarity between certain bivalves and the female pudenda. To the parts of one species of clam he gave the names vulva, labia, pubes, anus,andhymen. He grouped plants by the nature of their reproductive organs and endowed them with an arrestingly anthropomorphic amorousness. His descriptions of flowers and their behavior are full of references to “promiscuous intercourse,” “barren concubines,” and “the bridal bed.” In spring, he wrote in one oft-quoted passage:

Love comes even to the plants. Males and females . . . hold their nuptials . . . showing by their sexual organs which are males, which females. The flowers’ leaves serve as a bridal bed, which the Creator has so gloriously arranged, adorned with such noble bed curtains, and perfumed with so many soft scents that the bridegroom with his bride might there celebrate their nuptials with so much the greater solemnity. When the bed has thus been made ready, then is the time for the bridegroom to embrace his beloved bride and surrender himself to her.

He named one genus of plants Clitoria. Not surprisingly, many people thought him strange. But his system of classification was irresistible. Before Linnaeus, plants were given names that were expansively descriptive. The common ground cherry was calledPhysalis amno ramosissime ramis angulosis glabris foliis dentoserratis. Linnaeus lopped it back toPhysalis angulata , which name it still uses. The plant world was equally disordered by inconsistencies of naming. A botanist could not be sure ifRosa sylvestris alba cum rubore, folio glabrowas the same plant that others calledRosa sylvestris inodora seu canina . Linnaeus solved the puzzlement by calling it simplyRosa canina . To make these excisions useful and agreeable to all required much more than simply being decisive. It required an instinct—a genius, in fact—for spotting the salient qualities of a species.

The Linnaean system is so well established that we can hardly imagine an alternative, but before Linnaeus, systems of classification were often highly whimsical. Animals might be categorized by whether they were wild or domesticated, terrestrial or aquatic, large or small, even whether they were thought handsome and noble or of no consequence. Buffon arranged his animals by their utility to man. Anatomical considerations barely came into it. Linnaeus made it his life’s work to rectify this deficiency by classifying all that was alive according to its physical attributes. Taxonomy—which is to say the science of classification—has never looked back.

It all took time, of course. The first edition of his greatSystema Naturae in 1735 was just fourteen pages long. But it grew and grew until by the twelfth edition—the last that Linnaeus would live to see—it extended to three volumes and 2,300 pages. In the end he named or recorded some 13,000 species of plant and animal. Other works were more comprehensive—John Ray’s three-volumeHistoria Generalis Plantarum in England, completed a generation earlier, covered no fewer than 18,625 species of plants alone—but what Linnaeus had that no one else could touch were consistency, order, simplicity, and timeliness. Though his work dates from the 1730s, it didn’t become widely known in England until the 1760s, just in time to make Linnaeus a kind of father figure to British naturalists. Nowhere was his system embraced with greater enthusiasm (which is why, for one thing, the Linnaean Society has its home in London and not Stockholm).

Linnaeus was not flawless. He made room for mythical beasts and “monstrous humans” whose descriptions he gullibly accepted from seamen and other imaginative travelers. Among these were a wild man,Homo ferus , who walked on all fours and had not yet mastered the art of speech, andHomo caudatus , “man with a tail.” But then it was, as we should not forget, an altogether more credulous age. Even the great Joseph Banks took a keen and believing interest in a series of reported sightings of mermaids off the Scottish coast at the end of the eighteenth century. For the most part, however, Linnaeus’s lapses were offset by sound and often brilliant taxonomy. Among other accomplishments, he saw that whales belonged with cows, mice, and other common terrestrial animals in the order Quadrupedia (later changed to Mammalia), which no one had done before.

In the beginning, Linnaeus intended only to give each plant a genus name and a number—Convolvulus 1, Convolvulus 2,and so on—but soon realized that that was unsatisfactory and hit on the binomial arrangement that remains at the heart of the system to this day. The intention originally was to use the binomial system for everything—rocks, minerals, diseases, winds, whatever existed in nature. Not everyone embraced the system warmly. Many were disturbed by its tendency toward indelicacy, which was slightly ironic as before Linnaeus the common names of many plants and animals had been heartily vulgar. The dandelion was long popularly known as the “pissabed” because of its supposed diuretic properties, and other names in everyday use includedmare’s fart, naked ladies, twitch-ballock, hound’s piss, open arse , andbum-towel . One or two of these earthy appellations may unwittingly survive in English yet. The “maidenhair” in maidenhair moss, for instance, doesnot refer to the hair on the maiden’s head. At all events, it had long been felt that the natural sciences would be appreciably dignified by a dose of classical renaming, so there was a certain dismay in discovering that the self-appointed Prince of Botany had sprinkled his texts with such designations asClitoria, Fornicata,andVulva.

Over the years many of these were quietly dropped (though not all: the common slipper limpet still answers on formal occasions toCrepidula fornicata ) and many other refinements introduced as the needs of the natural sciences grew more specialized. In particular the system was bolstered by the gradual introduction of additional hierarchies.Genus(pluralgenera) andspecies had been employed by naturalists for over a hundred years before Linnaeus, andorder, class, andfamily in their biological senses all came into use in the 1750s and 1760s. Butphylum wasn’t coined until 1876 (by the German Ernst Haeckel), andfamily andorder were treated as interchangeable until early in the twentieth century. For a time zoologists usedfamily where botanists placedorder , to the occasional confusion of nearly everyone.[36]

Linnaeus had divided the animal world into six categories: mammals, reptiles, birds, fishes, insects, and “vermes,” or worms, for everything that didn’t fit into the first five. From the outset it was evident that putting lobsters and shrimp into the same category as worms was unsatisfactory, and various new categories such asMollusca andCrustacea were created. Unfortunately these new classifications were not uniformly applied from nation to nation. In an attempt to reestablish order, the British in 1842 proclaimed a new set of rules called the Stricklandian Code, but the French saw this as highhanded, and the Société Zoologique countered with its own conflicting code. Meanwhile, the American Ornithological Society, for obscure reasons, decided to use the 1758 edition ofSystema Naturae as the basis for all its naming, rather than the 1766 edition used elsewhere, which meant that many American birds spent the nineteenth century logged in different genera from their avian cousins in Europe. Not until 1902, at an early meeting of the International Congress of Zoology, did naturalists begin at last to show a spirit of compromise and adopt a universal code.

Taxonomy is described sometimes as a science and sometimes as an art, but really it’s a battleground. Even today there is more disorder in the system than most people realize. Take the category of the phylum, the division that describes the basic body plans of all organisms. A few phyla are generally well known, such as mollusks (the home of clams and snails), arthropods (insects and crustaceans), and chordates (us and all other animals with a backbone or protobackbone), though things then move swiftly in the direction of obscurity. Among the latter we might list Gnathostomulida (marine worms), Cnidaria (jellyfish, medusae, anemones, and corals), and the delicate Priapulida (or little “penis worms”). Familiar or not, these are elemental divisions. Yet there is surprisingly little agreement on how many phyla there are or ought to be. Most biologists fix the total at about thirty, but some opt for a number in the low twenties, while Edward O. Wilson inThe Diversity of Life puts the number at a surprisingly robust eighty-nine. It depends on where you decide to make your divisions—whether you are a “lumper” or a “splitter,” as they say in the biological world.

At the more workaday level of species, the possibilities for disagreements are even greater. Whether a species of grass should be calledAegilops incurva, Aegilops incurvata, orAegilops ovata may not be a matter that would stir many nonbotanists to passion, but it can be a source of very lively heat in the right quarters. The problem is that there are five thousand species of grass and many of them look awfully alike even to people who know grass. In consequence, some species have been found and named at least twenty times, and there are hardly any, it appears, that haven’t been independently identified at least twice. The two-volumeManual of the Grasses of the United States devotes two hundred closely typeset pages to sorting out all the synonymies, as the biological world refers to its inadvertent but quite common duplications. And that is just for the grasses of a single country.

To deal with disagreements on the global stage, a body known as the International Association for Plant Taxonomy arbitrates on questions of priority and duplication. At intervals it hands down decrees, declaring thatZauschneria californica (a common plant in rock gardens) is to be known henceforth asEpilobium canum or thatAglaothamnion tenuissimum may now be regarded as conspecific withAglaothamnion byssoides , but not withAglaothamnion pseudobyssoides. Normally these are small matters of tidying up that attract little notice, but when they touch on beloved garden plants, as they sometimes do, shrieks of outrage inevitably follow. In the late 1980s the common chrysanthemum was banished (on apparently sound scientific principles) from the genus of the same name and relegated to the comparatively drab and undesirable world of the genusDendranthema .

Chrysanthemum breeders are a proud and numerous lot, and they protested to the real if improbable-sounding Committee on Spermatophyta. (There are also committees for Pteridophyta, Bryophyta, and Fungi, among others, all reporting to an executive called the Rapporteur-Général; this is truly an institution to cherish.) Although the rules of nomenclature are supposed to be rigidly applied, botanists are not indifferent to sentiment, and in 1995 the decision was reversed. Similar adjudications have saved petunias, euonymus, and a popular species of amaryllis from demotion, but not many species of geraniums, which some years ago were transferred, amid howls, to the genusPelargonium . The disputes are entertainingly surveyed in Charles Elliott’sThe Potting-Shed Papers .

Disputes and reorderings of much the same type can be found in all the other realms of the living, so keeping an overall tally is not nearly as straightforward a matter as you might suppose. In consequence, the rather amazing fact is that we don’t have the faintest idea—“not even to the nearest order of magnitude,” in the words of Edward O. Wilson—of the number of things that live on our planet. Estimates range from 3 million to 200 million. More extraordinary still, according to a report in theEconomist, as much as 97 percent of the world’s plant and animal species may still await discovery.

Of the organisms that wedo know about, more than 99 in 100 are only sketchily described—“a scientific name, a handful of specimens in a museum, and a few scraps of description in scientific journals” is how Wilson describes the state of our knowledge. InThe Diversity of Life , he estimated the number of known species of all types—plants, insects, microbes, algae, everything—at 1.4 million, but added that that was just a guess. Other authorities have put the number of known species slightly higher, at around 1.5 million to 1.8 million, but there is no central registry of these things, so nowhere to check numbers. In short, the remarkable position we find ourselves in is that we don’t actually know what we actually know.

In principle you ought to be able to go to experts in each area of specialization, ask how many species there are in their fields, then add the totals. Many people have in fact done so. The problem is that seldom do any two come up with matching figures. Some sources put the number of known types of fungi at 70,000, others at 100,000—nearly half as many again. You can find confident assertions that the number of described earthworm species is 4,000 and equally confident assertions that the figure is 12,000. For insects, the numbers run from 750,000 to 950,000 species. These are, you understand, supposedly theknown number of species. For plants, the commonly accepted numbers range from 248,000 to 265,000. That may not seem too vast a discrepancy, but it’s more than twenty times the number of flowering plants in the whole of North America.

Putting things in order is not the easiest of tasks. In the early 1960s, Colin Groves of the Australian National University began a systematic survey of the 250-plus known species of primate. Oftentimes it turned out that the same species had been described more than once—sometimes several times—without any of the discoverers realizing that they were dealing with an animal that was already known to science. It took Groves four decades to untangle everything, and that was with a comparatively small group of easily distinguished, generally noncontroversial creatures. Goodness knows what the results would be if anyone attempted a similar exercise with the planet’s estimated 20,000 types of lichens, 50,000 species of mollusk, or 400,000-plus beetles.

What is certain is that there is a great deal of life out there, though the actual quantities are necessarily estimates based on extrapolations—sometimes exceedingly expansive extrapolations. In a well-known exercise in the 1980s, Terry Erwin of the Smithsonian Institution saturated a stand of nineteen rain forest trees in Panama with an insecticide fog, then collected everything that fell into his nets from the canopy. Among his haul (actually hauls, since he repeated the experiment seasonally to make sure he caught migrant species) were 1,200 types of beetle. Based on the distribution of beetles elsewhere, the number of other tree species in the forest, the number of forests in the world, the number of other insect types, and so on up a long chain of variables, he estimated a figure of 30 million species of insects for the entire planet—a figure he later said was too conservative. Others using the same or similar data have come up with figures of 13 million, 80 million, or 100 million insect types, underlining the conclusion that however carefully arrived at, such figures inevitably owe at least as much to supposition as to science.

According to theWall Street Journal , the world has “about 10,000 active taxonomists”—not a great number when you consider how much there is to be recorded. But, theJournal adds, because of the cost (about $2,000 per species) and paperwork, only about fifteen thousand new species of all types are logged per year.

“It’s not a biodiversity crisis, it’s a taxonomist crisis!” barks Koen Maes, Belgian-born head of invertebrates at the Kenyan National Museum in Nairobi, whom I met briefly on a visit to the country in the autumn of 2002. There were no specialized taxonomists in the whole of Africa, he told me. “There was one in the Ivory Coast, but I think he has retired,” he said. It takes eight to ten years to train a taxonomist, but none are coming along in Africa. “They are the real fossils,” Maes added. He himself was to be let go at the end of the year, he said. After seven years in Kenya, his contract was not being renewed. “No funds,” Maes explained.

Writing in the journalNature last year, the British biologist G. H. Godfray noted that there is a chronic “lack of prestige and resources” for taxonomists everywhere. In consequence, “many species are being described poorly in isolated publications, with no attempt to relate a new taxon[37]to existing species and classifications.” Moreover, much of taxonomists’ time is taken up not with describing new species but simply with sorting out old ones. Many, according to Godfray, “spend most of their career trying to interpret the work of nineteenth-century systematicists: deconstructing their often inadequate published descriptions or scouring the world’s museums for type material that is often in very poor condition.” Godfray particularly stresses the absence of attention being paid to the systematizing possibilities of the Internet. The fact is that taxonomy by and large is still quaintly wedded to paper.

In an attempt to haul things into the modern age, in 2001 Kevin Kelly, cofounder ofWired magazine, launched an enterprise called the All Species Foundation with the aim of finding every living organism and recording it on a database. The cost of such an exercise has been estimated at anywhere from $2 billion to as much as $50 billion. As of the spring of 2002, the foundation had just $1.2 million in funds and four full-time employees. If, as the numbers suggest, we have perhaps 100 million species of insects yet to find, and if our rates of discovery continue at the present pace, we should have a definitive total for insects in a little over fifteen thousand years. The rest of the animal kingdom may take a little longer.

So why do we know as little as we do? There are nearly as many reasons as there are animals left to count, but here are a few of the principal causes:

Most living things are small and easily overlooked.In practical terms, this is not always a bad thing. You might not slumber quite so contentedly if you were aware that your mattress is home to perhaps two million microscopic mites, which come out in the wee hours to sup on your sebaceous oils and feast on all those lovely, crunchy flakes of skin that you shed as you doze and toss. Your pillow alone may be home to forty thousand of them. (To them your head is just one large oily bon-bon.) And don’t think a clean pillowcase will make a difference. To something on the scale of bed mites, the weave of the tightest human fabric looks like ship’s rigging. Indeed, if your pillow is six years old—which is apparently about the average age for a pillow—it has been estimated that one-tenth of its weight will be made up of “sloughed skin, living mites, dead mites and mite dung,” to quote the man who did the measuring, Dr. John Maunder of the British Medical Entomology Center. (But at least they areyourmites. Think of what you snuggle up with each time you climb into a motel bed.)[38]These mites have been with us since time immemorial, but they weren’t discovered until 1965.

If creatures as intimately associated with us as bed mites escaped our notice until the age of color television, it’s hardly surprising that most of the rest of the small-scale world is barely known to us. Go out into a woods—any woods at all—bend down and scoop up a handful of soil, and you will be holding up to 10 billion bacteria, most of them unknown to science. Your sample will also contain perhaps a million plump yeasts, some 200,000 hairy little fungi known as molds, perhaps 10,000 protozoans (of which the most familiar is the amoeba), and assorted rotifers, flatworms, roundworms, and other microscopic creatures known collectively as cryptozoa. A large portion of these will also be unknown.

The most comprehensive handbook of microorganisms,Bergey’s Manual of Systematic Bacteriology , lists about 4,000 types of bacteria. In the 1980s, a pair of Norwegian scientists, Jostein Goksøyr and Vigdis Torsvik, collected a gram of random soil from a beech forest near their lab in Bergen and carefully analyzed its bacterial content. They found that this single small sample contained between 4,000 and 5,000 separate bacterial species, more than in the whole ofBergey’s Manual . They then traveled to a coastal location a few miles away, scooped up another gram of earth, and found that it contained 4,000 to 5,000other species. As Edward O. Wilson observes: “If over 9,000 microbial types exist in two pinches of substrate from two localities in Norway, how many more await discovery in other, radically different habitats?” Well, according to one estimate, it could be as high as 400 million.

We don’t look in the right places.InThe Diversity of Life , Wilson describes how one botanist spent a few days tramping around ten hectares of jungle in Borneo and discovered a thousand new species of flowering plant—more than are found in the whole of North America. The plants weren’t hard to find. It’s just that no one had looked there before. Koen Maes of the Kenyan National Museum told me that he went to one cloud forest, as mountaintop forests are known in Kenya, and in a half hour “of not particularly dedicated looking” found four new species of millipedes, three representing new genera, and one new species of tree. “Big tree,” he added, and shaped his arms as if about to dance with a very large partner. Cloud forests are found on the tops of plateaus and have sometimes been isolated for millions of years. “They provide the ideal climate for biology and they have hardly been studied,” he said.

Overall, tropical rain forests cover only about 6 percent of Earth’s surface, but harbor more than half of its animal life and about two-thirds of its flowering plants, and most of this life remains unknown to us because too few researchers spend time in them. Not incidentally, much of this could be quite valuable. At least 99 percent of flowering plants have never been tested for their medicinal properties. Because they can’t flee from predators, plants have had to contrive chemical defenses, and so are particularly enriched in intriguing compounds. Even now nearly a quarter of all prescribed medicines are derived from just forty plants, with another 16 percent coming from animals or microbes, so there is a serious risk with every hectare of forest felled of losing medically vital possibilities. Using a method called combinatorial chemistry, chemists can generate forty thousand compounds at a time in labs, but these products are random and not uncommonly useless, whereas any natural molecule will have already passed what theEconomist calls “the ultimate screening programme: over three and a half billion years of evolution.”

Looking for the unknown isn’t simply a matter of traveling to remote or distant places, however. In his bookLife: An Unauthorised Biography , Richard Fortey notes how one ancient bacterium was found on the wall of a country pub “where men had urinated for generations”—a discovery that would seem to involve rare amounts of luckanddevotion and possibly some other quality not specified.

There aren’t enough specialists.The stock of things to be found, examined, and recorded very much outruns the supply of scientists available to do it. Take the hardy and little-known organisms known as bdelloid rotifers. These are microscopic animals that can survive almost anything. When conditions are tough, they curl up into a compact shape, switch off their metabolism, and wait for better times. In this state, you can drop them into boiling water or freeze them almost to absolute zero—that is the level where even atoms give up—and, when this torment has finished and they are returned to a more pleasing environment, they will uncurl and move on as if nothing has happened. So far, about 500 species have been identified (though other sources say 360), but nobody has any idea, even remotely, how many there may be altogether. For years almost all that was known about them was thanks to the work of a devoted amateur, a London clerical worker named David Bryce who studied them in his spare time. They can be found all over the world, but you could have all the bdelloid rotifer experts in the world to dinner and not have to borrow plates from the neighbors.

Even something as important and ubiquitous as fungi—and fungi are both—attracts comparatively little notice. Fungi are everywhere and come in many forms—as mushrooms, molds, mildews, yeasts, and puffballs, to name but a sampling—and they exist in volumes that most of us little suspect. Gather together all the fungi found in a typical acre of meadow and you would have 2,500 pounds of the stuff. These are not marginal organisms. Without fungi there would be no potato blights, Dutch elm disease, jock itch, or athlete’s foot, but also no yogurts or beers or cheeses. Altogether about 70,000 species of fungi have been identified, but it is thought the number could be as high as 1.8 million. A lot of mycologists work in industry, making cheeses and yogurts and the like, so it is hard to say how many are actively involved in research, but we can safely take it that there are more species of fungi to be found than there are people to find them.

The world is a really big place.We have been gulled by the ease of air travel and other forms of communication into thinking that the world is not all that big, but at ground level, where researchers must work, it is actually enormous—enormous enough to be full of surprises. The okapi, the nearest living relative of the giraffe, is now known to exist in substantial numbers in the rain forests of Zaire—the total population is estimated at perhaps thirty thousand—yet its existence wasn’t even suspected until the twentieth century. The large flightless New Zealand bird called the takahe had been presumed extinct for two hundred years before being found living in a rugged area of the country’s South Island. In 1995 a team of French and British scientists in Tibet, who were lost in a snowstorm in a remote valley, came across a breed of horse, called the Riwoche, that had previously been known only from prehistoric cave drawings. The valley’s inhabitants were astonished to learn that the horse was considered a rarity in the wider world.

Some people think even greater surprises may await us. “A leading British ethno-biologist,” wrote theEconomist in 1995, “thinks a megatherium, a sort of giant ground sloth which may stand as high as a giraffe . . . may lurk in the fastnesses of the Amazon basin.” Perhaps significantly, the ethnobiologist wasn’t named; perhaps even more significantly, nothing more has been heard of him or his giant sloth. No one, however, can categorically say that no such thing is there until every jungly glade has been investigated, and we are a long way from achieving that.

But even if we groomed thousands of fieldworkers and dispatched them to the farthest corners of the world, it would not be effort enough, for wherever life can be, it is. Life’s extraordinary fecundity is amazing, even gratifying, but also problematic. To survey it all, you would have to turn over every rock, sift through the litter on every forest floor, sieve unimaginable quantities of sand and dirt, climb into every forest canopy, and devise much more efficient ways to examine the seas. Even then you would overlook whole ecosystems. In the 1980s, spelunkers entered a deep cave in Romania that had been sealed off from the outside world for a long but unknown period and found thirty-three species of insects and other small creatures—spiders, centipedes, lice—all blind, colorless, and new to science. They were living off the microbes in the surface scum of pools, which in turn were feeding on hydrogen sulfide from hot springs.

Our instinct may be to see the impossibility of tracking everything down as frustrating, dispiriting, perhaps even appalling, but it can just as well be viewed as almost unbearably exciting. We live on a planet that has a more or less infinite capacity to surprise. What reasoning person could possibly want it any other way?

What is nearly always most arresting in any ramble through the scattered disciplines of modern science is realizing how many people have been willing to devote lifetimes to the most sumptuously esoteric lines of inquiry. In one of his essays, Stephen Jay Gould notes how a hero of his named Henry Edward Crampton spent fifty years, from 1906 to his death in 1956, quietly studying a genus of land snails in Polynesia calledPartula . Over and over, year after year, Crampton measured to the tiniest degree—to eight decimal places—the whorls and arcs and gentle curves of numberlessPartula , compiling the results into fastidiously detailed tables. A single line of text in a Crampton table could represent weeks of measurement and calculation.

Only slightly less devoted, and certainly more unexpected, was Alfred C. Kinsey, who became famous for his studies of human sexuality in the 1940s and 1950s. But before his mind became filled with sex, so to speak, Kinsey was an entomologist, and a dogged one at that. In one expedition lasting two years, he hiked 2,500 miles to assemble a collection of 300,000 wasps. How many stings he collected along the way is not, alas, recorded.

Something that had been puzzling me was the question of how you assured a chain of succession in these arcane fields. Clearly there cannot be many institutions in the world that require or are prepared to support specialists in barnacles or Pacific snails. As we parted at the Natural History Museum in London, I asked Richard Fortey how science ensures that when one person goes there’s someone ready to take his place.

He chuckled rather heartily at my naiveté. “I’m afraid it’s not as if we have substitutes sitting on the bench somewhere waiting to be called in to play. When a specialist retires or, even more unfortunately, dies, that can bring a stop to things in that field, sometimes for a very long while.”

“And I suppose that’s why you value someone who spends forty-two years studying a single species of plant, even if it doesn’t produce anything terribly new?”

“Precisely,” he said, “precisely.” And he really seemed to mean it.