The Ox-Born Bee

Excursions into art and science

Tag: Pliny

The Dream of the Unicorn, Part 2: How to Invent an Animal (I)

In my last post I wondered what it means to “discover” something that doesn’t actually exist, or to describe something before we have knowledge of it. How much of the unicorn was discovered, and how much was invented? The unicorn was, I think we can all agree, invented, but the point of this post is to consider further this question of the unicorn’s discovery. And to ask, what role does invention—imagination—play in science?

The unicorn is more than a myth, more than wonder word: it sheds light on scientific understanding, in particular on the way analogy works in scientific understanding. Analogy is sometimes called a “predictive metaphor.” 1 While both analogies and metaphors offer comparisons, the comparisons that analogies make are not purely idiosyncratic (“red is the sound of a trumpet” 2, or “effectrix of divine honey” for bee) but predictive (“hand is to glove as foot is to _______”). For this reason, metaphors do not claim any special relationship between the two terms being compared. Rather, the relationship is in–and reveals–the mind of the metaphorist. Analogies, on the other hand, claim a certain knowledge-value: they help our minds move from known terms to unknown ones.

Another way of saying this is that analogies are, as the Stanford Encyclopedia of Philosophy notes, a species of “heuristic”: they provide “aids to discovery” based on the properties of a known thing, which we can extend to the properties of an unknown thing. Heuristics and analogies are like rough-and-ready sketches that allow our minds to approach the unknown. It would be tempting to say that metaphor is to poetry as analogy is to science, but I think a more accurate analogy for analogy would be, analogy is to science as the hand-drawn map is to territory. In other words, we don’t require a satellite-generated topo-map to navigate territory—often a hastily scrawled crayon drawing on a napkin with a few points of interest will get us close enough to our destination. 3

Pliny the Elder’s 1st-century CE description of the unknown beast first described by Ctesias reveals something of the sketchy, predictive power of analogy. In Pliny’s account, the beast

has the head of a stag, the feet of an elephant, and the tail of a boar, while the rest of its body is like that of the horse; it makes a deep lowing noise, and has a single black horn, which projects from the middle of its forehead, two cubits in length. This animal, it is said, cannot be taken alive. 4

The sources of these analogies to stag, elephant, boar, and horse in Pliny’s account are unclear. We know that Ctesias did not make such references to other creatures in his account, except to compare its astragalos, or knuckle-bones, to those of an ox. However, between Ctesias in the 5th century BCE and Pliny in the first century CE, we find a possible source in Gaius Julius Caesar’s first-century BCE Commentaries on the Gallic War. Caesar apparently did a little natural history when not conquering the Gauls, and provided a description of animal in the Hercynian forests of Germany:

an ox of the shape of a stag, between whose ears a horn rises from the middle of the forehead, higher and straighter than those horns which are known to us. From the top of this, branches, like palms, stretch out a considerable distance. The shape of the female and of the male is the, same; the appearance and the size of the horns is the same. 5

Andre Arbus's (1903-1969) Actaeon takes the form of Caesar's Hercynian unicorn. From Le Cabinet de Loup (the Stag & Wolf Room) at La Musee de la Chasse et de la Nature (Museum of Hunting and Nature), Paris, France. Author photograph.

Andre Arbus’s (1903-1969) Actaeon. From Le Cabinet du Cerf (the Stag Room) at La Musee de la Chasse et de la Nature (Museum of Hunting and Nature), Paris, France. The author apologizes for his blurry photograph.

In the above image, taken from the Stag Room of the Museum of Hunting and Nature, André Arbus’s statue of Actaeon, the Greek hunter transformed into a stag by the goddess Artemis for the crime of gazing on her while she bathed, takes the form of Caesar’s Hercynian unicorn. Arbus helps us see what Caesar thought he saw in the forest, and what Caesar thought he saw in turn might explain where Pliny got “stag.”

Walter Hyde, in “The Curious Animals of the Hercynian Forest” (1918), attempted to save the “sober historian” Caesar from trafficking in fables of “one-horned deer” and other chimera, noting that “it is now fairly well agreed among Caesar scholars that the whole account of the forest and its wonders is merely an interpolation into the body of Caesar’s work by some unknown scribe.” 6 So we may justly surmise that Pliny was a bit credulous to include this fabulous animal in his Natural History based on this and, before this, Ctesias’s limited accounts.

But then, how did Pliny arrive at his other comparisons? Is he—are all of these observers, from Ctesias forward—merely trafficking in fables as a result of some centuries-long game of telephone? Despite his own suspicion of Caesar’s account, Hyde may give us some clues. He notes that “It is well known that Roman writers called unfamiliar wild animals of large size boves, ‘oxen.’ Thus the elephant was known as the Lucanian ox…. Seals were also called ‘marine oxen.’” This is important, and reveals the analogical significance of Caesar’s—and Pliny’s— account that Hyde doesn’t quite understand, and which he in fact attempts to erase with the help of “unknown scribes”: it shows how one animal can become a heuristic, a map, to another. The animal itself ceases to be a collection of specific details and becomes a rough sketch for thinking, which is then used to compare to other animals in search of underlying similarities. Caesar was simply using “ox” and “stag” to describe something that was ox-large and stag-like. The only “fabulous” dimension of the animal is its single horn—and this would not have seemed especially fabulous to Romans carrying around with them ideas, like Ctesias’s, of single-horned animals.

Caesar and Pliny are employing some analogical reasoning based on such prior eyewitness accounts, using the parts of known creatures to account for the elements of the description of this unknown creature. They are, in a sense, modeling the unicorn using terms known to them and their audience. The destination might be unclear, but the coordinates they are using to plot the route are well known. They have, in other words, discovered a unicorn through analogy—predicting the existence of an unknown thing based on the existence of known things.

To think of these accounts this way reveals their real knowledge-value as heuristical, not simply empirical. In Gregory Bateson’s terms, they may have discovered, not a thing, but a “pattern which connects.” Pliny, in casting about for coordinates, might have freed the unicorn from its binding specificity and rendered it a tool for inquiry.

Bateson called this kind of thinking “transference,” or the seeking of underlying relationships between things—a kind of pattern-seeking in contrast to simple collecting or defining. Transference involves contextualizing details so as to allow for such pattern-recognition. His example is the elephant’s trunk:

What is the elephant’s trunk?…. As you know, the answer is that the elephant’s trunk is its “nose.”… And I put the word “nose” in quotation marks because the trunk is being defined by an internal process of communication in growth. The trunk is a “nose” by a process of communication: it is the context of the trunk that identifies it as a nose. That which stands between two eyes and a north of a mouth is a “nose,” and that is that. It is the context that fixes the meaning, and it must surely be the receiving context that provides meaning for the genetic instructions. When I call that a “nose” and this a “hand” I am quoting—or misquoting—the developmental instructions in the growing organism, and quoting what the tissues which received the message thought the message intended.” 7

Bateson is exploring the process by which we arrive at knowledge, a process I think is at work in early accounts of the unicorn. At the most basic level, we can call the elephant’s trunk its “nose” because of its context in relation to the rest of its features (above this, between that). The definition of “nose” ought not to be a list of characters: this would produce a venn diagram at whose center would be an absence—the noses of many species share a lot of overlap, but no two noses will ever be the same. Maybe we could say something about the “noseness” that all noses share, but that’s pretty metaphysical. Rather, the meaning of “nose” is its relationship to other features, its context. “Nose” is an analogy that reveals connections, relationships, rather than a set of characters.

(Bateson is also suggesting that this is more than a language matter: that the way we acquire our knowledge of the nose bears a relationship to how the nose acquires its knowledge of itself from its genetic instruction. The nose knows, indeed.)

Richard Owen's vertebrate pattern

Richard Owen’s vertebrate pattern

The unicorn is like the nose—it does not exist except in the form of relationships, homologies or samenesses among things. Caesar and Pliny, with their primitive, ready-to-hand, folk categories (ox, stag, horn, etc.), scanned the world for relationships and patterns that connect. Sure such a map can be wrong, because based on the wrong kinds of coordinates (observable and superficial, versus underlying and fundamental, for instance), or the misidentification of coordinates (the single horn is most likely a double). But it is surely the right kind of wrong—a wrong that reveals the mind that connects, that sees patterns. It might not be a stretch to say that the same pattern recognition that went into identifying the unicorn went into the nineteenth-century English naturalist Richard Owen’s identification of the pattern of all vertebrate life in the spine of a fish. Beyond the pattern, everything else is just fill-in-the-blanks, “know-how,” says Bateson.

But we lose the mind in common between Pliny and Owen when we, like Hyde or even Sir Thomas Browne, apply to them only our ham-fisted divisions between the real and the unreal, between waking and dream-life. When Hyde invents “unknown scribes” to rescue Caesar from his naivety, he may only be revealing his own—his inability to think past details to the patterns that connect. If there is a key difference between Classical and Modern thinking when it comes to science, as Hyde or Browne want to suggest, it is in those early naturalists’ willingness to base their knowledge on something other than empirical observation—namely, on imaginary categories (inventions) to be later filled with things (discovered). Men like Ctesias or Pliny dreamed first, and they dreamt in analogies.

In the case of the unicorn, the dream proved both more powerful and more elusive than the reality. To our better-informed modern eyes, these accounts reveal that the unicorn is likely not a single imaginary beast, but a collection or composite of many actual ones—a bestiary, a compendia, of creatures distilled into a single account.

Subsequent natural historians have spent a lot of time trying without success to parse the unicorn into its various components. Eighteenth-century French naturalist Georges Cuvier tried in his own way to put an end to the unicorn as a heuristic, hitching it to a single animal: the rhinoceros (Latin for rhino (nose) + ceros (horn)). This would certainly explain the single-horned appearance, the deep lowing noise, and the fact that the animal would have been hard to take alive. It would also explain the speed of the animal, given that a rhino gains in speed the farther it run due to its bulk. Likewise the ox. Moreover, rhinos are solid-hoofed, like the elephant, not cloven-hoofed, like many other ungulates.

Other features, though, are not accounted for: the 1 1/2 – 2 cubit-length horn; the animal’s color (white); its relative shape (ass- or possibly stag-like). The stag, the ox, the oryx, and the ass would also seem to be likely contenders, but again, these explain some but not all of the characters of the unicorn. It might point to a gazelle-like creature, like the scimitar oryx (Oryx dammah) of north Africa.

Arabian oryx. Getty images. Photo by Joe & Clair Carnegie/Libyan Soup.

Arabian oryx. Getty images. Photo by Joe & Clair Carnegie/ Libyan Soup.

But an oryx, like a stag, has two horns–unless of course you’re looking at one in profile and from a great way off. Further, the oryx is cloven-hoofed, meaning that the “feet like an elephant” (or, solid-hoofed) descriptor would rule out this animal. As Aristotle wrote, “Most of the horned ones are cloven-hoofed, e.g., the ox, the deer, and the goat; we have no solid-hoofed animal with a pair of horns.” Cloven-hoofed creatures can’t grow horns in the middle of their forehead because their skulls are divided down the middle, not solid. Finally, the geography is all wrong: north Africa is a ways off from India, and neither of which are close to the forests of Germany.

This is but a partial list of likely candidates for the unicorn. Chris Lavers, in his The Natural History of Unicorns, puts together a comprehensive history of this composite creature that includes even more animals archived within Ctesias’s and Pliny’s descriptions. These include the Tibetan kiang, a fleet animal that can outrun a greyhound, the Tibetan chiru, a notoriously elusive type of goat with long black horns, and the yak, a fierce and unpredictable type of cow.

The “discovery” of the unicorn, we might say, predicted, or at least anticipated, our knowledge of these other creatures whose existence was, at the time, equally unimaginable. In a sense, the invention—the dream—of the unicorn anticipates the existence of things that would only later emerge as real. We could say the early naturalists helped draw a map that led, maybe not to the destination they sought, but to a lot of other places.

This much is certain: someone somewhere saw something(s) they’d never seen before, which they framed, described, using the fragments of things they had seen. In doing so, they invented a known unknown. Call it a map, or maybe the first field guide into nature. Their analogies produced that venn diagram of overlapping circles, and at the center we expected the ding an sich, the thing itself. But instead, we found a pattern that revealed, and modeled, the existence of other unknowns in other contexts—rhino, oryx, kiang, chiru, yak. But some–men like Browne, Cuvier, or Hyde–mistook the pattern for an absence, a yawning emptiness that they called, somewhat angrily, a fable, a dream. Perhaps  they were just really disappointed: they were promised a unicorn. Perhaps they weren’t as taken with the ark of creatures we found instead.

Hercynian UnicornIn find it, if not analogous, at least metaphorical of this disappointment that Actaeon, the hunter-turned-stag, is, in a bit of unfortunate turnabout, torn to pieces by the dogs that once were his hunting companions.

The unicorn fared little better. It would eventually be destroyed by the very tools of science that it helped to fashion. More on that later. But unlike poor Actaeon, the unicorn did manage to live on, at least for a while, because a pattern is more powerful than a data point. Its unknown destination gave the idea of the unicorn legs, literally and figuratively, and on these it traveled from North Africa to India to Germany, and from the ancient world to the modern. How long those legs were will be the subject of my next post.


  1. Gillian Beer, Darwin’s Plots: Evolutionary Narrative in George Eliot and Nineteenth-Century Fiction. Cambridge, 2000. 
  2. I borrow this one from Thomas Nagel’s classic essay on the philosophy of mind, “What Is It Like to Be a Bat?” The Philosophical Review. 83:4 (1974). 435-50.
  3. And some say this kind of analogizing and model-making form the basis of how we think. See for example Gilles Fauconnier and Mark Turner, The Way We Think: Conceptual Blending and the Mind’s Hidden Complexities (Basic, 2003) and Douglas Hofstadter and Emmanuel Sander, Surfaces and Essences: Analogy as the Fire and Fuel of Thinking (Basic, 2013).
  4. Pliny, Natural History. Trans. John F. Healy. Penguin, 2004. 281.
  5. Caesar, Commentaries on the Gallic War. Trans. W. A. McDevitte and W. S. Bohn. New York: Harper, 1869. 27.
  6. Walter Woodburn Hyde, “The Curious Animals of the Hercynian Forest.” The Classical Journal 13. Jan. 1918.
  7. Gregory Bateson, Mind and Nature: A Necessary Unity. 1979. Hampton Press, 2002. 14.

The Dream of the Unicorn, part 1: The Origin of the Species

Half our days we pass in the shadow of the earth; and the brother of death exacteth a third part of our lives. A good part of our sleep is peered out with visions and fantastical objects, wherein we are confessedly deceived. The day supplieth us with truths; the night with fictions and falsehoods, which uncomfortably divide the natural account of our beings. And therefore, having passed the day in sober labours and rational enquiries of truth, we are fain to betake ourselves unto such a state of being, wherein the soberest heads have acted all the monstrosities of melancholy, and which unto open eyes are no better than folly and madness.

So writes the English doctor, essayist, and human curiosity Sir Thomas Browne (1605-82) in a short essay “On Dreams.” Browne’s division of daylight rational inquiry from nighttime fictions and falsehoods is a good place to begin an inquiry into the existence of unicorns, not least because Browne himself investigated the issue in his Pseudoxia Epidemica or Enquiries into very many received tenents  and commonly presumed truths (1672). Browne’s target is “vulgar” or popular errors–folk beliefs that persist despite his age’s burgeoning sense of reason. How, he wonders, are people so “ready with open armes to receive the encroachments of Error”?

Among those persistent errors regarding the natural world that peeved Sir Thomas are the beliefs that pigeons have no gall, that a bear shapes her cubs at birth like clay, that an ostrich will digest iron, that moles have no eyes. Browne likewise takes aim at the unicorn–a creature whose inclusion in the most comprehensive encyclopedia of animals of the time, Edward Topsell’s History of Four-Footed Beasts (1658), perhaps owes to the fact that that book was a translation of German naturalist Conrad Gesner’s Historiae Animalium (1551-58) written over a hundred years earlier. By Browne’s time, it’s more than likely he was dispelling the dreams of an age that had already awaken.

Edward Topsell, "Of the Unicorn." History of Four-Footed Beasts and Serpents. 1658.

Edward Topsell, “Of the Unicorn.” History of Four-Footed Beasts and Serpents. 1658.

But maybe this assessment, like Browne’s, is too hasty. Are we so sure unicorns don’t exist? This is the question I posed to my Science and Literature class in a recent lecture and which I want to explore here over a series of posts. I’ll eventually get around to answering the question, but first it’s helpful–and fun–to figure out exactly what a unicorn is before deciding that it never was.

I was talking about the history of the unicorns in a college class because it turns out that the unicorn is a great case study in the history of science. If you understand how the unicorn managed to make it all the way to the 17th century, you can understand a bit about how we come to know and understand the natural world.

For most of us, the unicorn is a childhood fantasy character–a cartoon adornment of school lunchboxes and Trapperkeepers™. I’m embarrassed to admit that as a young would-be artist, I drew a lot of unicorns, and they were all the same: magnificent white horse-like beasts with glowing horns that acted like lightning rods for rainbows. My unicorns were mostly the barely sublimated expression of pre-adolescent sexual desire for the lithe, long-haired ladies of my 5th and 6th-grade classes, to whom I freely gave them out. (Unless of course they were an excuse for a boy to draw rainbows….) They looked more or less like this, but with more rainbow:

Unicorn drawing

More recently I’ve been hearing the word “unicorn” as applied to something whose improbability is an index of its desirability, as in: “I need a shuttle service that gets me to LAX in under 35 minutes.” “You could just ride a unicorn.” This is actually a much older usage: a 1905 Dictionary of Slang and Colloquial English defines unicorn as “two men and a woman (or vice versa) working together.” Haha.

But the unicorn as an object of scientific investigation is a lot older still, and weirder. Probably the first descriptive account of it is from a 4th-century BCE Greek doctor and explorer named Ctesias of Cnidus, who is reported to have seen a unicorn during a trip to India, which he recorded in his work, the Indika. (That this work shares its name with a species of marijuana seems appropriate.)

At this time, India was a stand-in for all that was fantastic in the minds of ancient Greeks, just as the Americas would be two thousand years later for Renaissance Europeans. It was the edge of the known world and represented the limits of Greek knowledge. As such, it was, like Browne’s dreams, somewhere between the daylight of wakeful reason and the nighttime of fretful visions: things on the margins are either too large or too small, the feverish hallucinations of a culture’s ignorance and craving for curiosities. Among other things, Ctesias described giant roosters and men that lived impossibly long lives. The sun appears ten times larger in India than in Greece and the reeds grow to the height of ships’ masts. Conversely pygmies live there, too, who keep sheep the size of lambs and oxen the size of rams. Ctesias was the first to describe the Cynocephaloi, or dog-headed men, and the martichora, a creature with the face of a human, the body of a lion, and the tail of a scorpion. Such creatures would still haunt the Medieval imagination much later.

Ctesias also describes a “wild ass” the size of a horse, with a

white body, crimson head, and deep blues eyes. They have a horn in the middle of their brow one and a half cubits in length [or 68.58 cm or 27 in]. The bottom part of the horn for as much as two palms towards the brow  is bright white. The tip of the horn is sharp and deep vermillion in colour while  the rest in the middle is black. They say whoever drinks from the horn (which they fashion into cups) is immune to seizures and the holy sickness and suffers no effects from poison…. [Ctesias] also says that other asses, both tame and wild, and the other solid-hoofed animals have no astragalos [or astragalus, the ball-joint of the ankle] or bile in the liver. However, these creatures do have an astragalos and bile in the liver. The astragalos, which is similar in size and shape to that of an ox, is the most beautiful I have ever seen. It is as heavy as lead and the color of cinnabar even at its deepest points. This animal is extremely swift  and strong and neither horse  nor any other animal can overtake it in pursuit. It begins running slowly, but the longer it runs, the more speed it picks up as it exerts itself brilliantly. Usually this animal cannot be hunted, but when they bring their young to pasture and are surrounded by many men on horseback, they choose not to flee and abandon their colts; rather, they fight both with their horn and by kicking and biting. They kill many many horses and men, but they are taken down by the bow or javelin, as one could never capture them alive. Their flesh is inedible on account of its bitterness, but they are hunted for their horns and astragaloi.” 1

Thus, the unicorn. A single paragraph of description of an ass putatively written 2500 years ago. I say “putatively” because the text of the Indika was lost and so despite this “original” description, the unicorn as a species has no origin: the authority on which it’s based survives only as a series of quotations–a waking dream reported by a sojourner to a twilight land of wonders who may or may not have set foot there.

Ctesias’s authority, unlike that of the later, unimpeachable Aristotle, was not held in high esteem, probably because of his penchant for reporting wonders like the Cynocephaloi or the martichora. But as Ctesias translator Andrew Nichols argues, it’s possible that these wonders were of interest to later writers who preserved them and who passed over more mundane details that might have established Ctesias as an authoritative observer. For when Ctesias’s descriptions align with reality, they are quite accurate: later works refer to his description of the bittakos. a bird the size of a falcon with a red face and blue body and which can converse in Indian as well as Greek. This would have seemed wondrous indeed to a culture unfamiliar with parrots.

Despite the unbelievability of his accounts, they survive because they continued to circulate as citations among other historians, natural and otherwise. Even Aristotle, the ultimate authority of antiquity and who among all the early naturalists was probably the only one to insist on making actual observations of the natural world, recorded Ctesias’s account of the single-horned beast in his Historia Animalia, and did so without revealing any suspicion:

some animals are horned, some hornless. Most of the horned ones are cloven-hoofed, e.g., the ox, the deer, and the goat; we have no no solid-hoofed animal with a pair of horns. But a few, e.g., the Indian ass, have a single horn and cloven hooves. The only solid-hoofed animal with a huckle-bone [i.e., the astragalus or ankle-joint] is the Indian ass. 2

Into the Common Era, Roman encyclopedists like Pliny in the 1st-century and Aelian in the 2nd also kept unicorns in circulation. Together, these historians described a species that would live thousands of years in the European imagination before going extinct, a victim of the Enlightenment insistence on empirical evidence and falsification, of which Browne’s Pseudoxia is among the first examples.

If anything, Ctesias and his unicorn belong to a history of error more than to science. Ctesias probably never ventured beyond the Indus Valley in the north of India and thus never even knew of a subcontinent, and so his title itself is geographically misleading 3: it refers more to an idea, a fantasy, than an actual place. In addition, he was probably reporting the oral history of travelers from India rather than making observations first-hand. What’s more, his original record of these indirect accounts was eventually lost, and so even that evidence, such as it was, has little merit. And finally, what little evidence that remains has been distorted by the desire for curiosities of later writers who recorded–cited–these errors in their own too credulous attempts to catalog the natural world in encyclopedias that demonstrate less interested than we do in distinguishing between things reported and things real.

This would seem to be the end of the story: unicorns don’t exist. Except for a couple of things. First, including such an account in one’s own encyclopedia of the known world, however unreliable, makes good sense, doesn’t it? Someone said they saw something. They had no falsifying evidence, so it could be true. Why not include it for someone to disprove later, just in case? Isn’t that kind of curiosity and credulity part of the scientific spirit, if not method? Certainly the world held wonders yet undiscovered and travelers were bringing back more all the time.

But second, more than the spirit of inquiry, there is method: Not only does Ctesias’s account reveal that someone somewhere saw something, those details seem so tantalizingly specific that they cannot be ignored, not even by Aristotle. Such specificity is hard to discount. Something somewhere gave someone the vivid impression of a one-horned animal that exhibited some physical characters (color of coat; number, length, and color of horn; relative size; shape of hoof and ankle-bones; absence of bile; speed), which demonstrated some definite ethological characters (they defend their young aggressively; they attack with horn and teeth), which haunted a particular geography (roughly India; possibly the Himalayan plains; probably Tibet), and which possessed some cultural value in the form of commodities (the horn for drinking; the astragloi for gambling, as dice; the flesh for eating);and which lent itself to amusing stories (they kill many men and horses and cannot be taken alive).

Indeed, early accounts of the unicorn possess all the hallmarks of what we now know as natural history–the observation and description of life. Except for one thing: the creature discovered and described does not appear to have existed. If not the unicorn, what, then, did Ctesias discover? Is it possible to discover something that doesn’t exist? If Ctesias did not discover the unicorn (which at this point I am unwilling to admit), what he did was reveal the possibility of one, which may have been even more wondrous indeed. These are the subjects of my next post!


  1.  Ctesias on India and Fragments of his Minor Works. Trans. Andrew Nichols. London: Bristol Classics, 2011. 56
  2. Aristotle, Historia Animalia. Book II. Trans. A. L.. Peck. Harvard University Press, 1970. II.1.
  3. See Chris Lavers, The Natural History of Unicorns (Harper Perennial, 2010), who helps pinpoint some of the historical details of early accounts of the unicorn.

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