The migrants

Most people know of at least two reasons that organisms can evolve.  The first, of course, is natural selection; members of the same species with inheritable differences can have different survival rates or reproductive rates, leading to overall shifts in the genetic makeup of the population.  The second is catastrophe; a major external event, such as the eruption of the Siberian Traps or the collision of the Chicxulub Meteorite, can completely destabilize what had been a thriving ecosystem, and cause the selective pressures to go off in a completely different direction.  (The two I mentioned were the dominant factors in the Permian-Triassic and Cretaceous-Tertiary extinctions, respectively.)

Less well-known is the role that plate tectonics can play.  When two land masses split apart, the organisms then go their separate ways evolutionarily, especially once the two pieces drift far enough away from each other to experience significantly different climates.  This is what happened to Australia, which most recently was connected to Antarctica; once they diverged, Australia moved northward and Antarctica southward, resulting in just about everything in Antarctica becoming extinct as the temperatures dropped, and leaving Australia with its unique assemblage of species.

The opposite can happen when two continents run into each other.  This occurred when India separated from Africa and collided with Asia, about fifty million years ago, carrying with it species from the southern supercontinent (Gondwana) and introducing them to the northern one (Laurasia).  But an even more striking example occurred when North and South America got close enough that a bit of the seafloor was pushed above water, creating the Isthmus of Panama.

When this happened, on the order of three million years ago, it opened up an easy avenue of two-way migration between the two continents.  This reconnected land masses that had been separated since the breakup of Pangaea in the early Triassic Period, on the order of two hundred million years ago.  That's a long time for species assemblages to evolve in their own directions, and the result was two entirely different floras and faunas.  Those began to move back and forth across the gap as soon as the isthmus formed.

What is curious -- and still largely unexplained -- is why the survival rates of the northward and southward migrants were so drastically different.  Species went both directions; that much is clear from the fossil record.  But just looking at mammals, South America gained (and still has) various species of cats, wolves, foxes, peccaries, deer, skunks, bears, and mice that it gained from North America, to name only a few of the groups that moved in and thrived.  But going the other direction?

There were only three survivors.  The opossum, the armadillo, and the porcupine are the only mammalian South American imports we still have around today.  Others that attempted the northward trek, including ground sloths, glyptodonts, "terror birds," sparassodonts, notungulates, and litopterns, struggled along for a while but eventually became extinct.

[Image is in the Public Domain]

The surmise is that moving from wet forests where it's warm year-round into cooler, drier temperate deciduous forests or grasslands is harder than the reverse, just from the perspective of resources.  Whatever the reason, though, it altered the ecosystems of South America forever, as the North American species proved to be better competitors (and predators), driving entire families of South American mammals extinct.  Some groups continued to thrive and diversify, of course.  Hummingbirds come to mind; they're a distinctly South American group. increasing in diversity as you head south.  Where I live, there's a grand total of one species of hummingbird (the Ruby-throated Hummingbird).

The little country of Ecuador has 132.

The reason all this comes up is the discovery of the complete skeleton of an extinct species of porcupine in Florida, dating to 2.5 million years ago -- and therefore, one of those early migrants northward from its ancestral homeland.  It's related to the modern North American species, but definitely not the same; the extinct species, for example, had a prehensile tail, similar to modern South American species (and which our North American porcupines lack).  It's still unknown, however, if the Florida species is ancestral to our current North American porcupines, or if they're cousins; further study of the skeleton may help to resolve that question.

It's fascinating, though, to see the fingerprints of this mass migration that was to change so radically two different continents.  The process of plate movement continues; Australia will eventually collide with Asia, for example, with similar results, mixing together two sets of species that have been isolated for millions of years.  Change is inevitable in the natural world; it can happen quickly or slowly, and sometimes occurs in ways we're just beginning to understand.

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Drawn together

Convergent evolution occurs when only distantly-related species are under the same selective pressures, and evolve to look alike.  A particularly good example of this is the North American flying squirrel (a rodent) and the Australian sugar glider (a marsupial).  Put them side-by-side, and they're hard to tell apart, and both have the distinctive kite-like flap of skin between the forelegs and hind legs, allowing them to catch a breeze and glide from tree to tree.

It's important to emphasize that while convergent evolution can result in organisms being similar in appearance or habits, it doesn't ever cause them to fuse into a single species.  Flying squirrels and sugar gliders maintain major differences in their genetic make-up, skeleton, dentition, and so on -- so however close the resemblance, they're still two separate species.

Convergence is actually fairly common in the natural world, which is why appearance is such a poor guide to determining who is related to whom.  There are only so many solutions to the problems posed by living in a particular environment, so it's inevitable that different lineages will happen on the same ones.  Flying, for example, has evolved independently at least four times -- birds, bats, pterodactyloids, and insects.  The structure and mechanics is different in each, which is indicative that they were independent innovations.

I was thinking about convergent evolution this morning as I read a paper in the journal Geodiversitas about the discovery of a remarkable fossil in Colombia.  It's the best-preserved and most complete skeleton ever found of Anachlysictis gracilis, a Miocene apex predator that belonged to a group called the sparassodontids.  (The name comes from the Greek σπαράσσειν, to tear to pieces, and ὀδόντος, tooth -- an indicator of how scary these animals were.)

Here's a photograph of the skeleton:

[Image courtesy of Daniella Carvalho and Aldo Benites-Palomino]

My guess is that looking at this, you're immediately reminded of the saber-toothed cats such as the famous Smilodon, which also were around during the Miocene Epoch but reached their pinnacle a few million years later, during the Pleistocene.  Surprisingly, this parallels my earlier example of the flying squirrel and sugar glider -- the saber-toothed cats were true felids, and thus placental mammals, while Anachlysictus and the other sparassodonts were marsupials.  The two species were drawn together by the forces of convergent evolution.  If you're a predator, having big nasty pointy teeth is a pretty good adaptation regardless what taxonomic group you belong to.

These striking carnivores were present in South America during what is called the "splendid isolation," prior to the tectonic shift that formed the Isthmus of Panama and allowed for the Pliocene Great Biotic Interchange.  South America had developed a unique biota, including not only the sparassodonts but a variety of other marsupial groups, most of which are now extinct.  Even the South American placentals didn't do so well, and were outcompeted (or hunted to death) by North American migrants.  Not long after the formation of Central America, a great many of the South American groups -- not only the sparassodonts, but the glyptodonts, litopterns, astrapotheres, pyrotheres, and xenungulates -- were gone forever.

The new fossil discovery will allow paleontologists to make some deductions about not only its anatomy, but its behavior. "In a future study we will address all the other bones in its body, which include various sections of the spine, ribs, hip, scapulae -- what we call 'shoulder blades' for humans -- and bones in its legs," said Catalina Suarez, of the Argentine Institute of Nivology, Glaciology and Environmental Sciences, who led the research team.  "This will allow us to explore aspects of how it moved, the position in which its neck held its head, whether it was a runner, whether it could climb, whether its hands could hold objects more easily, as many marsupials do when feeding, or whether it was a bit more difficult, as it is for example for a dog or a cat."

It's fascinating to learn more about these long-extinct animals, whose ecological role would be taken over by predatory placental mammals like wolves and the various big cats.  Even if they're extinct, their bones still have a story to tell -- of a saber-toothed marsupial who hunted in the forests of Colombia thirteen million years ago.

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Rodents of unusual size

My writer friend Vivienne Tuffnell, of the lovely blog Zen and the Art of Tightrope Walking, frequently amuses her friends with photos of the antics of her pet guinea pigs.  Her love for her little pals is undoubtedly what prompted her to post a somewhat more alarming photo a couple of days ago:

She captioned it, "Guinea pigs and guinea biggers?"

What's most amazing about this is that the smaller animal isn't even a guinea pig; it's a capybara, the largest living rodent species.  On this scale, your typical guinea pig would about fit in the space underneath the capybara's belly.

So, who's the big guy?

That's Josephoartigasia, a Pliocene (five million to one million years ago) animal from southeastern South America that is thought to be the largest rodent species ever.  From skulls found in Uruguay, a full-grown Josephoartigasia weighed something like five hundred kilograms -- heavier than an adult grizzly bear.

It's hard to talk about this thing without lapsing into superlatives.  The one that blew me away was a calculation of its bite force, putting it at an estimated 950 Newtons, which is right around what an adult jaguar can exert.  Because of this, its skull was heavily reinforced; the more powerful the muscle contraction, the stronger the bones have to be (given that bones provide anchorage and leverage for the pull of the muscles).

What it needed this kind of bite force for is a matter of conjecture.  It's possible it was just for gnawing things.  Like granite outcrops, or something.  On the other hand, South America during the Pliocene was replete with huge predators including Xenosmilus, a sabre-toothed cat, and phorusrhacids -- the aptly-named "terror birds" that looked like a cross between an ostrich and a velociraptor.  So it's possible its fearsome bite was defensive.

When food is abundant and there are lots of large carnivores around, there is a significant evolutionary pressure favoring large body size, and that seems to be what happened here.  Back then, South America's fauna resembled what now lives in southern Africa -- abundant wildlife and lots of very big animals.  Josephoartigasia would have shared the habitat with giant ground sloths, glyptodonts (think "an armadillo on steroids"), toxodonts (the Pliocene answer to hippos), and the giant peccary Platygonus. 

So it was a world of megafauna, and Josephoartigasia fit right in.

But we're used to thinking of large ungulates; even giant ground sloths are familiar to anyone who's seen a kid's book on prehistoric animals.

But rodents the size of an adult longhorn steer are a little hard to imagine.

So thanks to Vivienne, who has provided cool topics for Skeptophilia before and definitely didn't fail me this time.  Me, I'm just as glad Josephoartigasia is not around any more.  I have enough of a hard time keeping squirrels out of the birdfeeder.

Having a cow-sized squirrel that could eat the birdfeeder would be another thing entirely.

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Islands in the sky

About fifteen years ago, I fulfilled a lifelong dream to go to Ecuador, a country I've been fascinated with since I was a kid.  I'm a fanatical birder, and that tiny country is home to no less than one-sixth of the world's nine-thousand-odd bird species, including over three hundred different kinds of hummingbirds.  (Where I live, in upstate New York, we have exactly one, and it's only here in the summer.)

It was when I was reading up on the hummingbirds in the Ecuadorian bird guide before leaving on the trip that I noticed something odd.  A number of the species had extremely narrow ranges.  A good example is the exquisite Violet-tailed Sylph (Aglaiocercus coelestis):

[Image licensed under the Creative Commons Joseph C Boone, Violet-tailed Sylph 2 JCB, CC BY-SA 4.0]

The Violet-tailed Sylph is only found in a narrow band a couple of kilometers wide on the Pacific slope of the Andes.  North-to-south, though, its range spans over sixteen hundred kilometers.  The reason for this bizarre geographical distribution is obvious if you consider the topography; the range of the Violet-tailed Sylph, and the majority of the other hummingbirds, is driven by altitude, so their ranges run in thin strips parallel to the Andes Mountains.  A lot of it has to do with food specialization; they're nectar-feeders, and many of them have bills shaped to fit only a single species of flower.  Many tropical plants are very temperature- and moisture-sensitive, and that depends strongly on altitude, so they have equally restricted ranges.  In the case of the lovely little Sylph, its food sources are mostly found in the cloud forests that run along the mid-slope of the Andes at an elevation of about a thousand meters.

The combination of phenomenal overall biodiversity with extremely narrow ranges that you find in Ecuador draws some parallels with the fascinating ecological model called island biogeography studied in the 1960s by Robert MacArthur and E. O. Wilson.  They were trying to find patterns to explain why some islands (such as Trinidad) have extensive and diverse ecosystems, and others (such as Tristan da Cunha) have very low diversity.  They found two factors that made the most difference; island size and the proximity of the island to the nearest mainland.

The dependence on island size is easy to see; the bigger the island, the more resources there are, and the greater the number of species it can support.  The proximity factor comes from the likelihood of immigration (defined as a new species arriving and becoming established); more distant islands are farther away from a source of new species.  The math gets a little complicated, but the basic gist is that islands end up in an equilibrium between immigration and extinction, and that equilibrium results in a predictably higher number of species on larger islands that are closer to the mainland.

Where this gets interesting is that the mathematical model even works for metaphorical islands -- marshes surrounded by desert, isolated springs and lakes, hydrothermal vents on the floor of the deep ocean, and -- as with our hummingbird -- narrow ecosystems in mountain ranges that are restricted by altitude.  In fact, it's this last one that got me thinking about this topic in the first place; last week, a really cool study by a team led by Martha Kandziora of Charles University (Prague) looked at diversity in African "sky islands," ecosystems high up on mountains that are defined by cold temperatures, low rainfall, and harsh sunlight.  The authors write:

Tropical alpine floras are renowned for high endemism, spectacular giant rosette plants testifying to convergent adaptation to harsh climates with nightly frosts, and recruitment dominated by long-distance dispersal from remote areas.  In contrast to the larger, more recent (late Miocene onward) and contiguous expanses of tropical alpine habitat in South America, the tropical alpine flora in Africa is extremely fragmented across small patches on distant mountains of variable age (Oligocene onward)...  Although some of the mountains are old... most lineages appear to have colonized the afroalpine during the last 5 or 10 My.  The accumulation of species increased exponentially toward the present.  Taken together with recent reports of extremely low intrapopulation genetic diversity and recent intermountain population divergence, this points to a young, unsaturated, and dynamic island scenario.  Habitat disturbance caused by the Pleistocene climate oscillations likely induced cycles of colonization, speciation, extinction, and recolonization.

One of the things driving the study is that these regions are seriously threatened by anthropogenic climate change.  While species like the Violet-tailed Sylph could potentially respond to warming trends by moving farther up-slope, the African sky islands have nowhere to go.  If the climate gets significantly hotter, the great likelihood is that these ecosystems with their unique and bizarre flora will simply disappear.

Tragic to think that we're losing biodiversity and in many cases only poorly understand what's being lost.  Perhaps these odd species with their extreme specialization and tiny ranges don't have much impact on our day-to-day lives, but without them, we would live in a sadly impoverished world.

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Explorer, scientist... and hoaxer

Ever heard of André Thevet?

Born around 1516 in Angoulême, France, he was educated in the convent school of that city, although his teachers recorded that as a child he was "more interested in reading books than he was in religion," which seems like a reasonable choice to me.  Be that as it may, he evidently decided religion was worth studying after all, because at the age of twenty he took his vows and became a Franciscan priest.

[All the images in the post are in the Public Domain]

He led a life that was pretty remarkable, especially as compared to most of the people of his day (even the well-educated ones).  With the blessing of Jean de Bar-le-Duc, Cardinal of Lorraine, he visited Egypt, Greece, Turkey, and Palestine -- and in 1555 set out with Nicolas Durand de Villegaignon, a French naval officer, to cross the Atlantic and explore the eastern coast of South America.

Now, keep in mind when all this was happening.  This is fifty years before the founding of Jamestown, Virginia.  It's ten years before the founding of St. Augustine, Florida, the oldest continuously-occupied city founded by Europeans in North America.

So no one in Europe knew much about the Americas at that point other than (1) they existed, (2) they were big, and (3) they were inhabited by people who weren't really all that receptive to a bunch of white guys showing up and saying "this is ours now."

But that didn't stop Thevet and de Villegaignon, who ended up in what is now Brazil, with their base of operations as the tiny settlement that ultimately would become Rio de Janeiro.  And this is where the story gets interesting.

Thevet was a self-styled naturalist, and he set about to document, describe, and draw all the interesting new plants and animals he found.  But the problem was, Thevet was also apparently a dedicated spinner of wild yarns.  So his book, Les singularités du France-Antarctique, has a few at least marginally accurate bits, like the sloth:

And this toucan:

But then, for reasons unknown, Thevet threw in some things like the succarath of Patagonia:

Which looks like he could use a good meal or two.  Then there's the camphruch, a sort of weird water unicorn thing (notice the webbed hind feet):

And the aloés, a sort of fish-goose mashup:

The yuanat, which apparently is the bastard child of a cat and an iguana:

And worst of all, the licorne-de-mer, which looks a bit like a giant fish with a chainsaw protruding from its forehead:

What strikes me about all of this is that I've been to South America (twice), and there's enough weird and fascinating wildlife there that you have to wonder what Thevet's possible motivation was for inventing all of this.  (I'm aware that some of this may have been quick glimpses followed by filling in the blanks in his memory with whatever came to mind.  I already noted the yuanat's resemblance to an iguana, and the saw-horn of the licorne-de-mer looks like the flat, toothed snout of a sawfish.  But still, a lot of it seems to have been spun from whole cloth.)

It's a question I've asked before -- what does a hoaxer get out of hoaxing?  Assuming there's not some obvious motivation like money?  Profit doesn't seem to be the issue here.  Thevet would likely have had precisely the same number of sales of his book, once he got back to France, with illustrations of real animals and plants as he did with all of this fanciful stuff that he'd clearly made up as he went along.  I mean, you don't need to exaggerate anything to see how bizarre the Pink Fairy Armadillo is:

Or the White-faced Saki:

Or the South American Tapir:

My guess is that he just got lazy, and decided it was more fun to sit on board ship and sip brandy and make up fanciful animals than it was tromping around the rain forest trying to see what was actually out there.

Thevet was hardly the only one who did this, of course.  The early days of European exploration were rife with examples of people coming back from ship voyages with bizarre tales of human tribes with their faces in the middle of their chests, people who had dogs' heads, people whose feet pointed backwards so their tracks would confuse anyone trying to follow them, a tribe whose members had enormous, pendulous elephant ears, and one-legged men with a single enormous foot that they used as a parasol on hot days (a legend used for wonderfully humorous effect in C. S. Lewis's The Voyage of the Dawn Treader).  I guess "yeah, we had a good trip and saw some cool people who looked basically like us only with darker skin" just wasn't good enough.

As amusing as all this may seem, I find this tendency maddening.  It's hard enough to figure out what's real and what's not under ordinary circumstances, but hoaxers complicate matters, and for no good reason other than a desire for notoriety.  So as much as I can chuckle at Thevet's duck/lion/unicorn, people like him set back the actual science of natural history significantly with their fairy stories.

I'd like to say that all of this is a thing of the past, but it's the same thing that motivates a lot of claims of cryptid-hunters, isn't it?  Now, I hasten to say that this doesn't invalidate all cryptid claims; as I've said many times before, there may really be something weird and unknown to biology out there lurking in the woods, lakes, or oceans.  But we have enough trouble dealing with the inevitable tendency of people (especially under high-adrenaline conditions) to exaggerate or misinterpret what they see and hear without the added complication of hoaxers making shit up.

So I encourage you to go to South America, which is a wonderful, diverse, fascinating, and huge place to explore.  It's home to over 300 species of hummingbirds (the eastern United States has a grand total of one), and countless other birds, reptiles, amphibians, mammals, insects, and assorted miscellany.  If you go there, though, watch out for cat-iguanas.  I hear they pack a nasty bite.

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Last week's Skeptophilia book recommendation was a fun book about math; this week's is a fun book about science.

In The Canon, New York Times and Pulitzer Prize-winning writer Natalie Angier takes on a huge problem in the United States (and, I suspect, elsewhere), and does it with her signature clarity and sparkling humor: science illiteracy.

Angier worked with scientists from a variety of different fields -- physics, geology, biology, chemistry, meteorology/climatology, and others -- to come up with a compendium of what informed people should, at minimum, know about science.  In each of the sections of her book she looks at the basics of a different field, and explains concepts using analogies and examples that will have you smiling -- and understanding.

This is one of those books that should be required reading in every high school science curriculum.  As Angier points out, part of the reason we're in the environmental mess we currently face is because people either didn't know enough science to make smart decisions, or else knew it and set it aside for political and financial short-term expediency.  Whatever the cause, though, she's right that only education can cure it, and if that's going to succeed we need to counter the rote, dull, vocabulary-intense way science is usually taught in public schools.  We need to recapture the excitement of science -- that understanding stuff is fun.  

Angier's book takes a long stride in that direction.  I recommend it to everyone, layperson and science geek alike.  It's a whirlwind that will leave you laughing, and also marveling at just how cool the universe is.

A botanical chameleon

One of the things I love most about science is its capacity to astonish us.

You can be really knowledgeable in a field, and then the natural world slings a curve ball at you and leaves you amazed.  Sometimes these unexpected twists lead to profound leaps in our understanding -- an example is the discovery of the parallel magnetic stripes in igneous rocks along the Mid-Atlantic Ridge leading to the theory of plate tectonics -- but sometimes it's just a fascinating bit of scientific trivia, one of those little things that makes you smile in a bemused sort of way and say, "Science is so cool."

I had a moment like that yesterday.  I taught biology for 32 years and have been interested in plants -- especially tropical plants -- a great deal longer than that.  I have a fine collection of tropical plants, currently jammed into my greenhouse so tightly that I can barely walk through it because the ones who spend the summer on my deck have to be tucked away in a warm place during our frigid winters.  I have bromeliads, cacti, three species of ginger, two different kinds of angel's trumpet (one of which got to be seven feet tall last summer, and sometimes had twenty giant, peach-colored flowers all blooming at once), a fig tree and a lime tree that produce every year, and two species of eucalyptus.

Among others.

While I wouldn't call myself an expert when it comes to tropical plants, I'm at least Better Than The Average Bear.  So I was startled to run, quite by accident, into an account of a species I had never even heard of -- and even more startled when I found out how truly bizarre and unique this plant is.

It's called the "chameleon vine," and its scientific name is Boquila trifoliolata.  It belongs to a small and rather obscure family of dicots called Lardizabalaceae, which contains forty species found in two places -- southeast Asia and western South America.  (How a group of plants with common ancestry ended up in such widely separated locales is a mystery in and of itself; populations like this are called peripheral isolates and are a perennial puzzle in evolutionary biology.)

Boquila is one of the South American ones, and lives in southern Chile and Argentina.  It's a woody vine whose leaves are composed of three leaflets (thus the plant's species name).  Here's a picture:

[Image licensed under the Creative Commons Inao, Boquila trifoliata [sic], CC BY-SA 2.0]

It's not really much to look at, and you non-botanical types are probably tapping your fingers and saying, "So what?"  But wait till you hear what this plant can do -- and why it merits its common name of "chameleon vine."

Boquila trifoliolata has an extraordinary ability called mimetic polymorphism.  It's capable of altering its leaf shape to mimic a variety of different (unrelated) plants -- including the ones it most commonly twines up as a support.  We're not talking about small differences, either.  It can be glossy or dull, have different petiole lengths, have different leaflet sizes and shapes, and even change whether or not it has serrations or spines along the edge!  

This ability, first described in a paper by botanists Ernesto Gianoli and Fernando Carrasco-Urra in Current Biology in 2014, was first attributed to genetic transfer from the host to the vine, a sort of genetic parasitism.  I'll admit that was the first explanation I thought of -- although how a plant could take up DNA from another species and only express the genes related to leaf morphology left me scratching my head a little.  But Gianoli and Carrasco-Urra were able to rule out this possibility, because Boquila can alter its leaf shape without touching the plant it's mimicking.

All it has to do is be nearby.  So it isn't a parasite at all.  The current guess is that Boquila is picking up volatile organic compounds emitted by the other plant, and those are altering gene expression, but those organic compounds have yet to be identified -- nor has any kind of specific mechanism by which that kind of alteration in phenotype could happen.

Even though we still have no idea how Boquila is managing this neat trick, the why is pretty clear.  If it's hiding amongst the foliage of another plant, herbivores can't single it out for a snack.  Gianoli and Carrasco-Urra found that when Boquila is climbing up a non-living support like a chain-link fence, herbivores actually seek it out for browsing.  But when it's camouflaged within another plant's leaves, it can avoid being seen and identified -- and, they found, browsing of its foliage dropped by as much as 50%.

Fascinating, isn't it?  And yet despite study, we haven't been able to figure out how the plant evolved this amazing (and apparently unique in the plant world) ability, nor what kind of information it's gleaning that might say, "Okay, time to change color and grow some spikes!"

So yet another example of how science is really freakin' cool.  It also illustrates how every new discovery opens up new avenues for investigation.  The crazy chameleon plant should make it absolutely clear that if you go into science, you'll never be done learning.

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Last week's Skeptophilia book recommendation was a fun book about math; this week's is a fun book about science.

In The Canon, New York Times and Pulitzer Prize-winning writer Natalie Angier takes on a huge problem in the United States (and, I suspect, elsewhere), and does it with her signature clarity and sparkling humor: science illiteracy.

Angier worked with scientists from a variety of different fields -- physics, geology, biology, chemistry, meteorology/climatology, and others -- to come up with a compendium of what informed people should, at minimum, know about science.  In each of the sections of her book she looks at the basics of a different field, and explains concepts using analogies and examples that will have you smiling -- and understanding.

This is one of those books that should be required reading in every high school science curriculum.  As Angier points out, part of the reason we're in the environmental mess we currently face is because people either didn't know enough science to make smart decisions, or else knew it and set it aside for political and financial short-term expediency.  Whatever the cause, though, she's right that only education can cure it, and if that's going to succeed we need to counter the rote, dull, vocabulary-intense way science is usually taught in public schools.  We need to recapture the excitement of science -- that understanding stuff is fun.  

Angier's book takes a long stride in that direction.  I recommend it to everyone, layperson and science geek alike.  It's a whirlwind that will leave you laughing, and also marveling at just how cool the universe is.

Knotty problem

As a language geek, the loss of our ability to understand communication from past civilizations always strikes me as tragic.

It's worse when that loss was the deliberate work of people trying to silence a culture.  This is the case with the strange and fascinating khipus (also spelled quipus), a set of strings with knots that the Incas used to encode something -- we're not sure what -- and which were systematically destroyed in the 17th century by the Spanish, who were suspicious of a system of communication they couldn't understand, and worried about how it might be used against them.

It's probable that they served more than one purpose -- as most written languages do -- one of which was enumeration.  There are current Andean societies that make at least limited use of khipus for keeping track of numbers of livestock,  But it's far from clear that this was their only use; after all, the Latin alphabet and Arabic numerals can be used for everything from shopping lists to censuses to history texts to telling a story.

[Image licensed under the Creative Commons Claus Ableiter nur hochgeladen aus enWiki, Inca Quipu, CC BY-SA 3.0]

Part of the problem with decoding them, however, is the same difficulty faced by anyone trying to decipher the Plougastel-Daoulas inscription that I wrote about a few days ago; there simply aren't many of them left.  The Spanish priests who gathered up and burned every khipu they could find simply did their job too well.

The other problem is the one I referenced in the same post, in connection to Linear B and the Voynich Manuscript; we don't even know how the knots correspond to units of language.  The type of knot seems as significant as the spacing, as does the color of the thread, but what any of those features mean is at this point speculation at best.

Another piece of the puzzle was added this week, however, in a paper authored by Alejandro Chu and Gary Urton in the journal Latin American Antiquity.  Chu has discovered 29 khipus at a site called Qolqawasi, and each one was found with quantities of edibles -- chili peppers, peanuts, and other regional crops.  This has led Chu and Urton to theorize that the khipus represented quantities of produce -- and, perhaps, the amount of taxes to be collected on it.  The authors write:

These khipus contain a formulaic arrangement of numerical values not encountered on khipus from elsewhere in Tawantinsuyu (the Inka Empire).  The formula includes first, a large number, hypothesized to record the sum total of produce included in a deposit, followed by a “fixed number,” and then one or more additional numbers.  The fixed number plus the additional number(s) sum to the original large number.  It is hypothesized that the fixed number represents an amount deducted from the deposit to support storage facility personnel.  As such, it represented a tax assessed on deposits, the first evidence we have for a system of taxation on goods in the Inka Empire.  It is proposed that the size and complexity of the storage facility at Inkawasi prompted the “invention” of a kind of financing instrument—taxation—not known previously from Inka administration. 

Their interpretation is not certain -- witness the number of times they use the word "hypothesized" and "proposed" -- but it's an intriguing possibility.  Whether the khipus were used for other purposes, such as in place of a written language, is still worth considering.  It's to be hoped that there will be additional discoveries of these odd artifacts, and that at some point the work of archaeologists such as Chu and Urton will lead to a complete decipherment -- and these voices from the past won't turn out to have been silenced completely.

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Aptly enough, considering Monday's post about deciphering scripts, this week's Skeptophilia book recommendation is Steven Pinker's brilliant The Stuff of Thought.  Here, experimental psychologist Pinker looks at what our use of language tells us about our behavior and neural wiring -- what, in fact, our choice of words has to do with human nature as a whole.

Along the way, he throws out some fascinating examples -- my favorite of which is his section on the syntax of swearing.  I have to admit, the question, "Just what does the 'fuck' in 'fuck you' actually mean?" is something I've never thought about before, although it probably should have given that I'm guilty of using the f-word a lot more than is generally considered acceptable.

So if you're interested in language, the human mind, or both, this is a must-read.  Although I'll warn you -- if you're like me, it'll leave you thinking, "Why did I just say that?" several times a day.

Equatorial travelogue

I just got back yesterday from my expedition to Ecuador with the phenomenal birding tour company Wings, an outfit which I cannot recommend highly enough.  As I mentioned in my previous post, I love Ecuador, but with the planning and leadership of a Wings guide, this was a really special trip.

We spent most of the time near the charming town of Mindo, in a lodge called Séptimo Paraiso (Seventh Heaven).   The name is apt.  The lodge was comfortable, the food was great, and the hikes and birding were stupendous.  In nine days I saw 273 species of birds.  (If you want to get an idea of the phenomenal biodiversity of this tiny country, you should know that 37 of the species I saw were different kinds of tanager, and 43 were hummingbirds.  For comparison purposes, here in upstate New York, we have two tanagers -- one of them quite rare -- and only one kind of hummingbird.)

Of course, the birds aren't the whole reason I love Ecuador.  The scenery is amazing, largely due to the steep-sided ridges and rushing rivers of the Andes.  The weather (where I was, at least) was refreshingly mild -- 80 F during the day, down to maybe 55 F at night.

Rio Mindo [all photographs, unless otherwise marked, were taken by me]

Séptimo Paraiso sits at 0 degrees, 0 minutes, 2 seconds south latitude.  That means the front door was, give or take, 200 feet from the Equator.  We used a GPS on one of our outings to find the exact spot -- within appropriate error bars, of course -- and I took a picture of our entire group straddling it.

The four people on the left are in the Northern Hemisphere, the four on the right in the Southern Hemisphere.

Besides the avifauna, the plant life is fantastic as well.  (And the two are intimately connected; the flora are usually specialized to be pollinated by one particular bird, butterfly, moth, or bat, so high diversity in fauna usually implies high diversity in flora.)  I consider myself a fairly competent field botanist, but I was seldom able to identify plants beyond family, and sometimes not even that.  That, of course, didn't stop me from appreciating them.

"Something in the amaryllis family" is the best I could do with this one.  But it sure is pretty, isn't it?

We did have more than a few truly stunning birds, of course.  Three of them that stand out in my mind are the rare Scarlet-bellied Dacnis, which our guide said we were really amazingly lucky to see:

[image courtesy of the Wikimedia Commons]

The Torrent Duck, which is somehow able to swim upstream in rivers that would easily knock a grown man off his feet:

[image courtesy of the Wikimedia Commons]

And a Crimson-mantled Woodpecker that positively modeled for the camera:

[image courtesy of the Wikimedia Commons]

One of the difficulties of birding as a hobby, however, is that it does not cater to late risers.  I consider myself something of a lark, but after six days of getting up at four in the morning, it was beginning to wear on me a little:

Me in the lounge at Séptimo Paraiso, waiting for some kind soul to bring me a glass of wine and rub my aching feet

The altitude was also a bit tricky.  On day trips into the highlands, all of us became breathless after even brief walks uphill.  The highest we went was 14,400 feet, at Papallacta Pass, but it was foggy and spitting rain (and windy and about 35 F), so I didn't get any pictures.  I did get a few nice shots of Yanacocha, at 13,200 feet:

I'm hoping that all of this hiking around up in the mountains will translate to better endurance for running here at home.  We'll see how that goes.

Anyhow, all in all it was a fantastic trip.  To end this, here are a few things I learned about Ecuador on this trip:

• The Ecuadorian people are, by and large, some of the nicest, most generous people on Earth.  Despite my toddler-level Spanish (more on that in a moment), I was greeted everywhere by smiles and waves. 
• That said, if you put your typical Ecuadorian behind the wheel of a car, watch out.  Passing zones, lanes, speed limits, and even stop signs are considered gentle suggestions at best.  Horns are used to communicate a variety of things, such as, "Hi," "Get the hell out of my way," and "My car has a horn."  The last full day of birding, I was with a guide named Jorge, who is a friendly young man who laughs a lot and has an encyclopedic knowledge of South American birds, and who turns into a complete lunatic when he turns the key in the ignition of his truck.  (He crossed himself every time he got into the driver's seat.  I'm not sure if I was supposed to consider this a good sign or a bad sign.)  He was the one who drove us up to the aforementioned Papallacta Pass.  He gave me a big grin as he turned off the highway onto something that barely qualified as a road.  I can say honestly that of the ten scariest things that have happened to me in my life, seven of them happened in the next half-hour.  We drove steadily uphill on narrow dirt roads with potholes the size of lunar craters, large stretches of which had a rock wall on one side and a hundred-foot drop (sans guard rails, of course) on the other.  I think I left permanent finger dents in the door handle of Jorge's truck.
• If you are going to travel in a country with 250 different species of hummingbirds, don't wear a red shirt.  Hummingbirds consider humans in red shirts to be enormous flowers.  You will spend the entire day dodging small, brightly-colored, feathery projectiles, and trying not to scream like a little girl.
• Bring enough cash along.  Neither my credit card nor my bank access card worked in the Ecuadorian ATM machines, for reasons I still have yet to figure out.  (I had called and notified my bank about my trip prior to leaving, so it wasn't that they thought my card(s) had been hacked and put a stop on them.)  This put me in the uncomfortable position of having to purchase things only at places that accepted credit cards, which was about 5% of the places we went.
• The food is amazing.  They have fresh fruits whose names I could barely pronounce, but which are beyond delicious.  I also had ceviche that has my mouth watering just remembering it.
• My one big regret about this trip is that I didn't put some time into learning more Spanish.  I don't ever want to be That Guy -- the American who goes abroad and expects everyone to speak English and do things the way they're done back home.  The Ecuadorians were remarkably gracious about my pathetic mangling of their language, however; my last day in Quito, I got a grinning thumbs-up from a waiter after ordering a surf & turf, a glass of red wine, and a bottle of mineral water at a restaurant, all in Spanish.  I'm sure he was on some level humoring me, but still, it was nice.  So if you go to another country, spend the six months before you go learning some of the language.  It goes a long way.

Anyhow, there you are -- a brief travelogue of a wonderful country.  I know I'll be back.  You can't do justice to a place like this in just one or two short visits.

I'm thinking a few years would do the trick.