Category Archives: Pedantry

Basically Everything is Worms

I was reading a piece by Melissa Hogenboom on the currently-recognised 35 different…well, let’s call them kinds of animals. A few years back I’d have been happy calling them phyla, but a phylum, like other rigid taxonomic ranks, is becoming unfashionable these days, as is the idea than all evolutionary trees fit neatly into same hierarchical categories. It’s a bit like how forms that want your postal address assume you have a state and ZIP code. (New Zealand has never has states, and when I was a kid there were no postcodes either.)

Nevertheless, the idea of fundamental difference in basic body plans is an interesting one; currently there are 35 different ways of being an animal. Some of these ways are enormously successful, others barely exist. There are over a million species of arthropods, 100,000 chordates (including us), 11,000 cnidarians, 1,200 ribbon worms, 100 comb jellies, 11 species of horseshoe worms, and a single kind of placozoan.

Most of these 35 groups contain just a few hundred species, or even fewer; the animal kingdom seems to have a “long tail”. In the literal sense, too, since the most common animal body plan is some kind of worm.

all35kindsofanimals

Hogenboom apparently had some difficulty preparing her story, particularly having to extract usable photographs from the one or two researchers working on some of the more obscure groups. I feel her pain. Still, when you’re the world expert on a family of tiny parasites that only live in squid kidneys, I doubt you have a press kit ready.

Ducks and Horses

A certain amount of nonsense has been written about duck-sized horses and horse-sized ducks, and it’s time to set the record straight.

In an online Q&A session back in August, President Obama was asked, “Would you rather fight 100 duck-sized horses or one horse-sized duck?” The Atlantic wrote a cheerful article about Obama’s choice (horse-sized duck), but the biologists they hastily recruited as fact-checkers were obviously operating outside their specialty. I feel it’s rather a shame Obama staffers neglected to consult me, as that question was, in essence, my PhD topic; I could have given the President better advice, and explained why his intuition—that a single giant duck would be an easier fight—is wrong, wrong, wrong.

The Fight

Ground rules: in the immortal tradition of Flash Gordon or Star Trek, the President finds himself alone in an arena, armed only with what he can improvise (“Your drones will not help you now, Mr President”). He’s faced with two doors: behind each are the opponent(s) he must defeat in order to, I don’t know, save the Earth. Which should he choose?

Horse-Sized Duck

A good-sized horse weighs 500 kg, or half a metric ton. What would a half-tonne duck look like, exactly? The problem is most people aren’t thinking of the biological scaling laws, known as allometry, that come into play when you make animals larger or smaller. While I’m sure John Eadie, the conservation ecologist quoted by The Atlantic, knows his field, he’s just wrong to imagine a giant duck would be dealing terrible blows with its enormous wings. It would be flightless, and its wings would be reduced to tiny stubs or have vanished altogether.

(Were you imagining a horse-sized duck would just be a mallard duck scaled up to the size of a horse? Well, if you’re happy with it collapsing to the ground wheezing, unable to walk or breathe, be my guest, but ignoring allometry wouldn’t make for much of a fight.)

obamadromornis

The closest thing to half-tonne ducks we have in the fossil record are Gastornis, sometimes known as Diatryma, from Europe and North America, and the dromornithids of Australia. Both were enormous moa-sized birds, related to ducks and geese, with huge sturdy legs and gigantic sharp beaks. They’re sometimes thought to be scavengers or fruit-eaters, but were likely predators similar to the better-known but unrelated phorusrachids of South America. Dromornis stirtoni, one of the largest birds ever, approached 500 kg and has even been nicknamed “the demon duck of doom” by Australian paleontologists, in their playful way.

Duck-Sized Horses

What’s a typical duck? I had to measure many, many duck bones to come up with a model for estimating body mass from femur diameter. There are over 100 species of ducks, and they range from less than 300 g (10 ounces) to about 4 kg (9 lbs); the “average duck” weighs about 700 g, the same as a guinea pig. That’s smaller than you would think, but more of a bird’s volume is made up of feathers than most people realise, now that we no longer pluck our own game.

What would a duck-sized horse look like? The smallest horse that springs to mind for most people is the ancestral Eohippus, famously “fox-terrier” sized, but actually about 30 kg according to more recent models (such as MacFadden’s in his 1994 book on fossil horses), so about 40 times too large for our purposes. When we scale animals up and down in size, allometry—the laws of physics—has far more effect on their appearance than their ancestry does. A dog-sized horse has body proportions about that of a dog; a guinea-pig sized horse would look pretty much like a guinea pig.

eohippusguineapig

Wouldn’t about 100 of them be fairly formidable, though? The herding behaviour of horses and other large herbivores lets them spot predators and defend themselves if necessary, but that only works if predators are roughly the same size as them. For a predator 100 times your size, the only response is not to try and swarm it, but to flee in terror.

Conclusion

President Obama weighs about 80 kg. Should he try to take down a 500 kg bird, with its powerful kick and huge razor-sharp beak, using just his bare hands? Or should he rather face 70 kg of terrified guinea pigs, which would require nothing but stout footwear? If the Earth’s fate is in the balance, the choice is clear, and it’s a specific instance of a general law I once came up with: nothing in evolution (or imaginary arena combat) makes sense except in the light of allometry.

Nine Problems with Looper (that Aren’t Brain-Melting Time Paradoxes)

Director Rian Johnson does his best to head off the complaints of those paying attention. “If we talk about [time travel] we’re gonna be talking about it all day, making diagrams with straws,” protests one of the characters. And yet this is a time travel movie, one in which the plot revolves around people being physically yanked back in time and trying to change the past. If it were just a story about how we wouldn’t take the advice of our older selves if it were on offer, the plot mechanic could have been something nice and low-budget like mysterious emails from the future. Instead we have Bruce Willis with gold strapped to his back and gunplay galore.

If a director claims they’re making a “serious” time travel movie, rather than some Hollywood nonsense starring Arnold Schwarzenegger, we’d expect them to at least acknowledge, if not grapple with, some of the intricacies science fiction novels (and indeed physicists) have been dealing with for decades. On this front Looper isn’t Primer or Donnie Darko, or even the best time travel movie starring Bruce Willis (that would be Twelve Monkeys). It blithely ignores the Grandfather Paradox, or contingent vs quantum-forking models of time travel, or the Hitler’s Murder paradox. The only way to send a message to your future self seems to be to carve it into your skin, rather than get a discreet tattoo, or just memorise it as done in one movie with a more sophisticated theory of time travel, Bill and Ted’s Excellent Adventure. Nobody in Looper seems to have thought of sending time machines and maintenance manuals back in time, which would create the bootstrap paradox we see in the Terminator movies (starring Arnold Schwarzenegger). Even Jeff Daniels’s ability to affect the future with terse hints (“I’m from the future. Go to China.”) is dealt with better in a time-travel episode of My Little Pony. Seriously, it is.

But OK, Rian Johnson, you don’t want to talk about time travel because it gives you a headache and reminds you of dull afternoons doodling in the margins of your math textbook (did you know Brick was filmed in Johnson’s actual old high school?). We can leave that to others. Here are some plot holes that don’t revolve around mind-bending time paradoxes. No real spoilers here, by the way, but it’ll help if you’ve seen the film.

A central plot conceit is that loopers execute themselves. You’re sent a victim, it turns out to be you 30 years older, but hey, old-you comes with a big pile of gold to help make the next 30 years more bearable. Of course, if you recognised your older self it might be hard to pull the trigger (a hesitation required by the plot) of your really, really inaccurate gun (also required by the plot). Telekinesis, however, is completely superfluous to the plot and just an excuse for some cool CGI.

  1. Why do loopers exist? Because it’s impossible to inconspicuously murder people in the future. Forensic science in 2074 is so amazingly advanced that victims are sent back to 2044 to be shot in broad daylight and stuffed in an incinerator (no chance of future cops noticing that, I’m sure!) Meanwhile, in 2074: “So our nanobots and DNA sniffers have traced the kidnapped man all the way to the door of this illegal time machine, and then he just disappears. Oh well, file this one under Unsolved.”
  2. But OK, let’s accept that premise: time machines are used to dispose of bodies. So why send the victims back alive? Or, if creating a corpse would still be too messy, why not at least render them unconscious? A wee knock on the head, if not a lethal injection, and there’s much less chance something might go terribly wrong in the past.
  3. But for some reason victims must be sent back alive and conscious. Why, though, have loopers murder themselves? Isn’t that just asking for trouble? Instead have them execute a retired looper they’ve never met, from far away, preferably someone who doesn’t even speak their language. Much safer.
  4. You know what? You have a time machine. Can you really not think of a better way of disposing of people without leaving a trace? Go send them to play with dinosaurs or watch Krakatoa erupt.
  5. Hold on—why, exactly, are retired loopers executed? It can’t be to keep them quiet—they’re left peacefully alone for 30 years, and could at any time blab the awful things they know about the impending discovery of time travel and all the people they killed. Why not just send back a pile of gold and a thank-you card and let them have a dignified retirement and die of old age? There’s plenty of gold to spare, as time machines can make piles of it in a few hours. (Wait, what? See below.)
  6. Also, those retired loopers may not be conveniently available for execution. It would be a bit awkward, wouldn’t it, if a looper died of cancer before their 30 year retirement was up. Or commited suicide the day before they were kidnapped, or spent those 30 years finding some foolproof way to hide. Or became President. Or ascended the criminal ranks until they were the one in charge of retired-looper execution. Or sneaked into a time machine after 29 years and got sent back to live their retirement a second time, except older and wiser and knowing when the stock market crashes.
  7. By the way, did everyone notice that Bruce Willis was kidnapped in China, but appeared in a cornfield in Kansas? That means time machines are also teleportation devices that can move something human-sized from one spot on Earth to any other, undetectably. And instantaneously; in fact you can arrive a few minutes before you leave (which I suppose gives you time to make a quick phone call and confirm to yourself that you’ll get there safely). The people who own time machines could easily dispose of bodies by just teleporting them to the bottom of the ocean—no risk of time paradoxes.
  8. In fact, since these outlaws with time machines can, and do, send themselves into the past to live and run criminal gangs, why aren’t they already in charge? Why haven’t they gone back to 2012, or 1812, to mess with history to their own advantage, so that when time travel is invented they’re ruling the world rather than having to hide murders from the authorities? They should be the authorities; after all, they have huge amounts of gold.
  9. That’s because it’s easy to make staggering riches with a time machine; you just need a gold bar and a bank vault. Send the gold to the vault a week into the past. Go to the bank, check the vault—yep, one bar of gold—withdraw it, and repeat the process: send bar back, go to bank, withdraw bar, send bar back—all day if you like. Next, send yourself a note, a few days in the past, with instructions to go to the vault, withdraw the huge pile of gold that’s accumulated there, cash it in, and bank the proceeds, but—very important—leave one bar behind. Finally, check your bank balance: hey, you’re rich. Not bad for a day’s work, and no tedious messing about with ancient savings accounts and compound interest rates.
  10. But what if past-you withdrew, oops, EVERYTHING from the bank vault and didn’t leave any seed money. Does the pile of gold suddenly disappear? Do you create a new parallel universe where past-you rich but a different future-you finds the vault empty? Now we’re dealing with time paradoxes. I’ll stop because we could be here all day. Making diagrams with straws.

Extra Credit Biology Questions

  1. Which king died from eating too many lampreys?
  2. Which Roman emperor saved a slave from being thrown to the lampreys?
  3. What’s the green stuff in the yolk of hard-boiled eggs, and how do you stop it appearing?
  4. Where can one see Arnold Schwartzeneggar’s handprints (not just footprints) on public display?
  5. What problem does the Scarecrow face when he gets his brain?
  6. There’s a science fiction story I read once where a mad scientist operated on crocodiles to repair the imperfect septum in their heart and make it four-chambered. The crocs became frisky, agile, and started putting on weight. What happened to them ultimately?
  7. What’s the major scientific flaw in this story?
  8. How many Philistines did Samson slay with the jawbone of an ass?
  9. Why an ass?
  10. When did people stop calling the stuff in your head ‘your brains’ and start calling it ‘your brain’, and why?
  11. Do people really eat live monkey brains?
  12. Which bit of the cow’s stomach tastes nicest?
  13. How can you tell that skeleton on the banner belonged to a bird, and was it a bird that could kick you to death?

What, if Anything, is Big Bird?

Years ago, when I was in the early stages of my PhD, I gave a joke presentation at a graduate student conference on the taxonomy and evolution of Big Bird. It was the sort of thing you’d see at any conference on avian evolution: a Latin name, reconstructed skeleton, possible place on the great evolutionary tree of birds. The tone was completely serious, despite the subject matter—the sort of thing that might be found in the Journal of Irreproducible Results back when it was funny.

Then, in the storage cabinets of the Berlin Museum of Natural History one summer’s day, I had a revelation—an original scientific insight that I am happy now to share with the world. I realised what kind of bird Big Bird almost certainly is, and figured out something of its evolutionary history.

I presented my findings at the Christchurch PechaKucha #8 in May, and now the audio and (more-or-less) synchronised slides have been uploaded. (A pecha-kucha is a talk in which 20 slides play for exactly 20 seconds each, and the speaker tries to keep up.) All the science is real, and no Big Birds were harmed in the course of this research. Enjoy.

Slide01

(This talk was BoingBoinged, twice! And I got a mention on the NPR blog too, so my status as card-carrying member of the Liberal Elite is forever assured.)

I also tweeted from Christchurch PechaKucha #8, as the format seemed well-suited to Twitter.

First, a pronunciation lesson from Mark Dytham: Pe-CHACH-ka. Perhaps easier to say if you’re drunk. • The effects of being in a car crash described as a “rapid decline in function” by a medical student. • “In 1981, Queenstown was less like Aspen, more like Twin Peaks.” • “Spotlight is my happy place: everybody else is so miserable there.” Chloe Geoghegan showed us her lovely embroidered naive signwriting. • The Master of Ceremonies got progressively drunker and more touchyfeely over the course of the evening. Called Christchurch “Auckland” not once but three times. • Jo Burzynska coined the word Oenomatapeia: music made from recording the sounds of rustling vines and gurgling fermenting wine. • The best quote of the night: “I had a recurring dream about a man putting me in the ground, cutting me up, and turning me into women’s bottoms.” • And an awkward moment afterwards: well-wishers complimented my deadpan jokes, like claiming to have a “PhD in giant flightless birds”. Yuk yuk.

Wincing Whirligigs, Batman!

jacket_the_canon.jpg The Canon
Natalie Angier
Houghton Mifflin, 2007
ISBN: 0618242953
A whirligig tour of the beautiful basics of science. The subtitle says it all. Natalie Angier provides a one-chapter crash course on each of the natural sciences, and the scientific method and probability to boot. Worthy stuff, and I’ve been looking for a single volume like this; something I can give to my friends and family, not too demanding, but enough science to excite them and help them see things a little bit from my nerdy point of view. It’s not a long book (although the designer cheats with very tight linespacing), and Angier is a New York Times reporter with a Pulitzer. So why did it irritate me so much that I reached the end only through sheer bloody-mindedness, audibly wincing every few pages?

Like I said, the subtitle says it all. We know what a whirlwind tour is, but what the heck is a whirligig tour? Poetically, one that’s hectic and constantly changing; literally, it’s a pinwheel, a brightly-coloured child’s toy that’s amusing and pointless. An unfortunate metaphor, and the first of many. Angier loves slapdash metaphors. Also flowery turns of phrase, obscure and only somewhat-appropriate words, zany non-sequiturs, and alliteration (e.g., the beautiful basics in the subtitle). Here’s a typical paragraph.

Scientific notation works just as well for the furtive as for the discursive, although in this case you’re talking about powers of one-tenth rather than powers of ten. One-tenth of one-tenth is one-hundredth, written as 10-2; one-tenth of one-hundredth is one-thousandth, or 10-3. Keep biting the right-handed bit of Alice’s toadstool. Down you go, you’re a fractionated Italianate family. You’re milli — a thousandth, 10-3; or micro — a millionth, 10-6; or nano — a billionth, 10-9; or pico — a trillionth, 10-12; or femto — a millionth of a billionth, 10-15.

Some people might like this sort of wordplay, but it gives me hives–and it’s not even good wordplay. Furtive for small is nice, but since when did discursive mean big? Meandering and full of digressions, like Angier’s metaphors, yes, perhaps expansive, but only incidentally large. And what’s up with Italianate? Does she mean Latinate (although the prefixes are actually Greek)? Or do Nano and Pico sound like comical Italian names? (Pico Iyer’s the only Pico I know of, and his name’s Indian.) Lastly, the Lewis Carroll reference is just a bit too sloppy: it’s a mushroom, not a toadstool (an important distinction, if you’re eating it). And it makes you grow taller and shorter, not bigger and smaller–in the original, Alice elongates and contracts like a caterpillar.

Every page is like this. Angier plunders the dictionary for shiny words: proptosically, vinculum, slub, and surl. As she flails for synonyms, the soup of particles in stellar formation becomes a cosmic chowder or a plasmic bisque, until the star and the metaphor collapse in a ball of baklava, whatever that’s supposed to look like. Every page has its pun, mostly lame. Pop culture allusions abound but are random and baffling rather than illuminating. And lists of three or more things always, without exception, conclude with something wacky.

…one might find organisms that take in nutrients, excrete waste, replicate, and actually use the fondue set they got as a wedding present.…

As for Pluto and Sedna and others of their subcompact class, whether you consider them planets, dwarf planets, planetismals, planet parodies, or Planters party mix…

Dave Barry it’s not. Which is a shame, because if you can get past the florid language she does a pretty good job of explaining one or two core concepts from each of chemistry, physics, astronomy and so on. There are some factual blunders, as you’d expect in a book covering all of science–I only picked up the biological ones. She says the platypus comes from New Zealand, and the carpal is just a single bone. Those hackneyed tetrapod forelimbs get trotted out again (she’s got me doing it now), and they’re poetically called homonyms–words that sound the same but have different meanings–but her metaphor is almost exactly backwards: bat and cat forelimbs are superficially different but share a deep, homologous, structure. Most importantly, she constantly confuses the fact of evolution (using examples from the fossil record) and Darwin’s theory; the fossils she cites support descent with modification but not natural selection.

It’s a shame. Angier is an great science journalist, but The Canon‘s enthusiasm has a whiff of anxiety, as if she was so worried about getting through to the science-averse that her entire rhetorical bag of tricks was upended on the table. If you’re happy to sort though the pile for the good stuff, you’ll enjoy this book more than I did. But I’d still rather recommend Bill Bryson.

Motherhood Handwaving

In the New York Times Magazine on March 4, Sharon Lerner argued that “making it easier for women to work may be the best way to increase birthrates.” Certainly most European countries think so; all have some form of paid maternity leave, and many are trying to increase it. Lerner goes on to note a paradox, though:

“Curiously, Europe’s lowest birthrates are seen in countries, mostly Catholic, where the old idea than the man is the breadwinner and the woman is the child-raiser holds strong. Portugal, Spain, Italy, and Greece have among the lowest fertility rates in Western Europe. Meanwhile, countries that support high numbers of working women, like Finland, Norway and Denmark, have among the highest birthrates.”

That is curious, isn’t it? Stereotypically, Catholics breed like rabbits, while the ultra-modern Scandinavians are the ones who forget to have children. I was so intrigued that I decided to check. I pulled the relevant data from Wikipedia (specifically, birthrates, paid maternity leave, and prevalence of Catholicism) and ran some quick stats.

euromaternity.gif Surprisingly, there’s no statistically-significant relationship between the amount of maternity leave a country offers and its birthrate. The highest birthrates on the graph, by the way, are in Ireland, Iceland, and Cyprus. The lowest is Germany’s. As you can see, Spain and Greece are not especially low; in fact, they’re about average for Europe, as is Sweden, which offers by far the most generous parental leave. And contrary to Lerner’s claim, Portugal actually has a higher birthrate than Finland.

These statistics aren’t occult knowledge. It took me two minutes with Google and Wikipedia to find the numbers, and not much longer to type them into Excel and make some graphs. Don’t magazines employ fact checkers anymore?

eurocatholicism.gif I couldn’t think of an simple stat that measures a country’s sexism (sorry, I mean “traditional attitude towards women”), but the amount of Catholicism in a given population is a matter of record. There’s another surprising result if you plot popery against birthrate. It looks like both Lerner and the stereotype are wrong–Catholics are having neither more nor fewer babies than anyone else. (If anyone can think of how to test the sexism hypothesis, let me know. Better still, do the analysis yourself, post the graph, and send me the link.)

Why this disparity between the article’s claims and the data? I’m not a demographic theorist, and I’m completely ignorant of the extensive literature on birthrates. But if one wanted to claim that maternity leave raises fertility, the first problem to overcome, surely, is that the numbers don’t back you up. One possible response would be lots of handwaving to convince readers that it only seems like you’re wrong; in this case, mysterious hidden factors just happen to precisely counteract the positive effects of maternity leave.

It doesn’t help, though, that the quote above contains some basic factual errors, as well as a couple of weasel phrases (“among the lowest…in Western Europe”). Neither inspire confidence. Of course, they also raise the suspicion that the researchers’ conclusions have been decided in advance, and the numbers are being cherry-picked (which is the other way to deal with unhelpful data). Which strategy is being employed here? I don’t know. But it’s wonderful that we can fact-check on a Sunday morning from the comfort of our living rooms.

The World’s Population in a Big Box

How big a box would you need for everybody?

Well, how much space do people take up? Assuming an average human mass of 65 kg, and a density of close to 1 (since we only just float), a person occupies 65,000 cubic centimeters. In theory you could pack about 15 people in a cubic meter (or 1,000,000 cubic centimeters). That seems like a lot, doesn’t it? Let’s check. It turns out the record for stuffing smallish undergraduates into a telephone booth is 22, and a phone booth is about 1.3 cubic meters inside. And remember, the folks near the bottom of the Big Box will be somewhat…compressed. Nevertheless, let’s assume an average of 13 people per cubic meter, since those near the top won’t be so packed so tightly.

The current world population is 6.6 billion. At 13 people per cubic meter, that’s a 507,692,308 m3 box; if it’s a cube, the Big Box is 798 m on each interior side. Say we make it an even 800 m (which allows for another 56 million people, probably as many as will be born by the time we’ve wrangled everyone inside). Don’t ask me how thick the walls would need to be; I’m not an engineer.

Exactly how big is a box 800 m a side? That’s half a mile. The World Trade Center was 417 m high. The box would take up 32 city blocks in Manhattan; it’d fit neatly into a fifth of Central Park.

The world’s population thus occupies an eighth of a cubic mile. All together we’d weigh 430 metric megatons. The pressure on the poor folks at the bottom would be half a ton per square inch, or 64 atmospheres–in fact, what you’d feel nearly half a mile deep in the ocean. The sea of humanity indeed.

Obviously you’d want to be one of the last inside the Big Box. How many people would be left standing when it was filled? The area of the top of the box is 640,000 m2, and a common estimate for crowd density is 6 people to the square meter. That means nearly 4 million people get to stand on top of everybody else; coincidentally, about the population of New Zealand. Lucky Kiwis!

bigbox.png

Spotting Fake Critters

aanimals.jpg Astonishing Animals
Tim Flannery; illustrated by Peter Schouten
Atlantic Monthly Press, 2004
ISBN: 0871138751

Why do biologists find the aliens of science fiction laughable? Because we know a little about how bizarre and inventive evolution is, and it’s a lot more imaginative than most screenwriters. The aliens on Star Trek were duller than what you could find in your own back garden. Tim Flannery, a biologist and museum director who writes regularly for the New York Review, and wildlife artist Peter Schouten collaborated on A Gap In Nature (Atlantic Monthly Press, 2001), know that truth is stranger than fiction, and aim to prove it by showcasing 90-odd amazing animals.

But the brilliant twist, mentioned almost in passing by the authors, is this: one of the animals is imaginary. And not just imaginary in an obvious way, like the dull chimeras of Greek mythology. Imaginary in a cunning biological way, a perfectly plausible beast that happens through an oversight of evolution not to exist. So reading the book becomes simultaneously an exercise in skeptical puzzle-solving. As a zoologist myself, surely it wouldn’t be hard to spot the fake? Guess again. In the first pass through the book, everything looked perfectly plausible, or equally implausible. It was time to get serious.

Flannery’s an authority on the mammals of New Guinea, so he’s in the best position to invent, say, a undescribed tree-kangaroo that only inhabits a remote and imaginary valley. How about the black dorsopsis, which, we’re told, never lays the full length of its tail on the ground (only the tip), for fear of leeches? Yeah, right. Very funny, Flannery. But oops, it really does exist. Back to the drawing board.

One way to invent an animal would be to come up with a minor twist on something that already exists. Easy, but it seems like cheating. He shows four species of bizarre pipefish; would he have the gall to slip in a fifth that’s a slightly different color or shape? Nope, all the pipefish are real.

Another cheat would be to invent an analogue of a real species, but transplant it to a different continent, a cheap trick evolution pulls all the time. (Dougal Dixon relies on this in his alternative-evolution book The New Dinosaurs, and that’s what made it so disappointing.) How about the sail-tailed lizard, which looks something like the marine iguana of the Galapagos, but transplanted to Indonesia? No, that one exists.

Biologists have no real advantage here, because the world is too rich. Biological training is too specialized for someone to know lots about mammals, amphibians, birds, and fishes. At best it’s pick any three. And that’s leaving aside the invertebrates, which Flannery largely does. The whole book could have been restricted to ants alone, and would be no less amazing—are you listening, E. O. Wilson?

(Hey, Google can’t find the pygmy chameleon (Brooksia minima)! No, it’s just a typo. Brooksia is a type of plant; the chameleon is Brookesia. Damn.)

In fact, a biologist would probably find it harder to pick out imaginary animals. We know too much about how weird the world is. Something that would make a lay person boggle and say “you’re kidding, right?” is all too plausible. Sometimes science is accused of reducing the sense of wonder–actually, it shows us the world is more amazing than our limited imaginations.

(The Sulawesi naked bat would be my pick, except I happen to know it exists. “Often crawling with a large species of earwig which lives nowhere else.” True, but reality’s even stranger. It’s a flightless parasitic earwig; in fact, there are two species of them.)

The even-more-feverishly brilliant trick? Flannery might be lying. All these animals might be real. If it’s a lie, it’s a fiendishly clever one. After a while the parade of natural wonders in the book might make even the most wide-eyed and naive reader a little jaded. But adding a puzzle forces us to critically examine every entry, looking for telltale implausibilities. Having to pick just one is the killer. If we knew a handful of animals were imaginary, we could write off all the most implausible; but deciding we’re found the fake, then turning the page to see something even more far-fetched, and knowing one of the two must exist, is a little mind-blowing.

(Found it! Finally! Perfectly plausible, and in fact more plausible than the creature it’s an analogue of, with a killingly odd little factoid—like the leech-avoiding tail—added to fool us. It’s the…)