Wanderlust

Maybe it's because I'm fundamentally a home body, but I find it really hard to understand what could have driven our distant ancestors to head out into uncharted territory -- no GPS to guide them, no guarantee of safety, no knowledge of what they might meet along the way.

A couple of years ago I wrote a piece about the extraordinary island-hopping accomplished by the ancient Polynesians -- going from one tiny speck of land to another, crossing thousands of kilometers of trackless ocean in dugout canoes.  We don't know what motivated them, whether it was lack of resources on their home islands, being driven away by warfare, or simple curiosity.  But whatever it was, it took no small amount of skill, courage, and willingness to accept risk.

The wanderings of the ancestral Polynesians, though, are hardly the only example of ancient humans' capacity for launching out into the unknown.  Two papers this week look at other examples of our forebears' wanderlust -- still, of course, leaving unanswered the questions about why they felt impelled to leave home and safety for an uncertain destination.

The first, which appeared in PLOS-One, looks at the similarity of culture between Bronze-Age Denmark and southwestern Norway, and considers whether the inhabitants of Denmark took a longer (but, presumably, safer) seven-hundred-kilometer route, crossing the Strait of Kattegat into southern Sweden and then hugging the coast until they reached Norway, or the much shorter (but riskier) hundred-kilometer crossing over open ocean to go there directly.

While the direct route was more dangerous, it seems likely that's what they did.  If they'd skirted along the coastline, you'd expect there to be more similarity in archaeological sites along the way, in the seaside areas of southern Sweden.  There's not.  It appears that they really did launch off in paddle-driven boats across the stormy seas between Denmark and Norway, four thousand years ago.

"These new agent-based simulations, applied with boat performance data of a Scandinavian Bronze Age type boat," the authors write, "demonstrate regular open sea crossings of the Skagerrak, including some fifty kilometers of no visible land, likely commenced by 2300 B.C.E., as indicated by archaeological evidence."

Considering people twice as far back in time, a paper this week in Nature describes evidence that seafarers from what is now Italy crossed a hundred kilometers of ocean to reach the island of Malta.  A cave in Latnija, in the northern Mellieħa region of Malta, has bones of animals that show distinct signs of butchering and cooking -- and have been dated to 8,500 years ago.

[Image licensed under the Creative Commons Frank Vincentz, Malta - Mellieħa - Triq il-Latnija - Paradise Bay 05 ies, CC BY-SA 3.0]

"We found abundant evidence for a range of wild animals, including Red Deer, long thought to have gone extinct by this point in time," said Eleanor Scerri, of the University of Malta, who was the paper's lead author.  "They were hunting and cooking these deer alongside tortoises and birds, including some that were extremely large and extinct today...  The results add a thousand years to Maltese prehistory and force a re-evaluation of the seafaring abilities of Europe's last hunter-gatherers, as well as their connections and ecosystem impacts."

What always strikes me about this sort of thing is wondering not only what fueled their wanderlust, but how they even knew there was an island out there to head to.  I know that patterns of clouds can tell seafarers they're nearing land, but still -- to launch off into the open ocean, hoping for the best, and trusting that there's safe landing out there somewhere still seems to me to be somewhere between brave and utterly foolhardy.

I guess my ancestors were made of sterner stuff than me.  I'm okay with that.  Being a bit of a coward has its advantages.  As Steven Wright put it, "Eagles may soar, but weasels don't get sucked into jet engines."

So if y'all want to, you can take off in your dugout canoes for parts unknown, but I'm gonna stay right here where it's (relatively) safe.  I suppose it's a good thing our forebears had the courage they did, because it's how we got here.  And I hope they wouldn't be too embarrassed by my preference for sitting on my ass drinking coffee with cream and sugar rather than spending weeks at sea nibbling on dried meat and hardtack and hoping like hell those clouds over there mean there's dry land ahead.

Chacun à son goût, y'know?

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Fishmobile

I know Life Follows Art, and all, but somehow I didn't expect the Art to be a sketch from Monty Python.

If you're a Python fan, you might remember a bit between Michael Palin and John Cleese, where Cleese plays a guy in the office that issues pet ownership licenses, and Palin is a guy who wants to get a license for his pet fish, Eric.

After being told that there are no licenses for pet fish, the following conversation takes place.

Cleese: You are a loony. 

Palin:  Look, it's a bleedin' pet, isn't it?  I've got a license for me dog, Eric.  I have a license for me cat, Eric. 

Cleese:  You don't need a license for your cat. 

Palin:  I bleedin' well do, and I've got one!  Can't be caught out, there. 

Cleese:  There's no such thing as a bloody cat license. 

Palin:  (places a piece of paper on the counter)  What's that, then? 

Cleese:  This is a dog license with the word "dog" crossed out and "cat" written in in crayon. 

Palin:  Man didn't have the right form.

Well, it turns out that they got the kind of license wrong, is all.  You don't need a license to own a fish, but the fish itself might need a license to drive a car.

In a paper that you'll think I'm making up, but I'm not, four researchers at the Ben-Gurion University of the Negev (Israel) have created a little car for a goldfish -- that is driven by the fish.

Dubbed the "Fish-Operated Vehicle" (FOV), it's a small plastic aquarium on four wheels, with a steering mechanism controlled by the orientation and fin-movement rate of the fish.  They then attached a food pellet dispensing device, so that the fish got fed whenever it moved its little car toward a pink stripe on the wall.

The authors write:

[The fish] were able to operate the vehicle, explore the new environment, and reach the target regardless of the starting point, all while avoiding dead-ends and correcting location inaccuracies.  These results demonstrate how a fish was able to transfer its space representation and navigation skills to a wholly different terrestrial environment, thus supporting the hypothesis that the former possess a universal quality that is species-independent.

Which is cool, and all, but it does make me wonder: how did they even think of doing this?  You know, this is the reason I'd never have made it in research science.  This isn't Thinking Outside the Box, this is Thinking in a place where the Box wouldn't even be visible through a powerful telescope.  I can't imagine in a million years being a behavioral scientist, and thinking, "Hey, I know!  Let's teach a fish how to drive a car!"

In any case, it's kind of cool that fish can be trained.  You have to wonder what's going through their tiny brains once they find out they can control where the car goes.  I'd like to think that it's the fish version of "Yeeeeee-haw!"

But what's next?  Maybe I can get them to come teach my dogs to mow my lawn.  It's about time they learn a useful skill.  (The dogs, not the researchers.)  On the other hand, now that I think about it, knowing my dogs they'd probably just use the lawn mower as a way of further terrorizing the local squirrels, so maybe it's better if they stay with all four feet on the ground.

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One of my favorite writers is the inimitable Mary Roach, who has blended her insatiable curiosity, her knowledge of science, and her wonderfully irreverent sense of humor into books like Stiff (about death), Bonk (about sex), Spook (about beliefs in the afterlife), and Packing for Mars (about what we'd need to prepare for if we made a long space journey and/or tried to colonize another planet).  Her most recent book, Fuzz: When Nature Breaks the Law, is another brilliant look at a feature of humanity's place in the natural world -- this time, what happens when humans and other species come into conflict.

Roach looks at how we deal with garbage-raiding bears, moose wandering the roads, voracious gulls and rats, and the potentially dangerous troops of monkeys that regularly run into humans in many places in the tropics -- and how, even with our superior brains, we often find ourselves on the losing end of the battle.

Mary Roach's style makes for wonderfully fun reading, and this is no exception.  If you're interested in our role in the natural world, love to find out more about animals, or just want a good laugh -- put Fuzz on your to-read list.  You won't be disappointed.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Science shorts

Today, I want to look at some awesome shorts that were too good to pass up.

No, not that kind.

In the last couple of days I found three recent bits of research that are just plain cool, and I couldn't resist sharing them with you.

First, we have a new discovery out of China showing that flowering plants were around a great deal earlier than we'd thought -- the early Jurassic Period, 174 million years ago.  This pushes back the earliest evidence of flowering plants by a good fifty million years!

Called Nanjinganthus dendrostyla, this little flower grew during a time when we'd thought there was nothing much around, botanically speaking, but gymnosperms (relatives of today's spruces, firs, and pines), ferns, and other more primitive plants.  But a fantastically well-preserved group of fossils has shown that they shared the space with some of the earliest angiosperms, or flowering plants.

One of the Nanjinganthus dendrostyla fossils 

After careful microscopic analysis of the flower, the researchers put it together like this:

So cool, even if it's not something you'd necessarily want as the centerpiece of your garden.

The significance of the discovery goes beyond its age.  There are some other features that bear mention, as is described over at the blog In Defense of Plants (linked above):

Another surprising feature is the presence of an inferior ovary that, by its very definition, sits below the sepals and petals.  It has long been hypothesized that early angiosperms would exhibit superior ovaries so this discovery means that we must rethink our expectations of how flowers evolved.  For instance, it suggests we may not be able to make broad inferences on the past based on what we see in extant angiosperm lineages.  It could also suggest that the origin of flowering plants was not a single event but rather a series of individual occurrences.  It could also be the case that the origin of flowering plants occurred much earlier than the Jurassic and that Nanjinganthus represents one of many derived forms.  Only further study and more fossils can help us answer such questions.

The second story comes from zoology, and it concerns eyeless cave fish -- fish whose ancestors were trapped in dark caves, and evolved to lose their visual sense.  There's a fundamental misunderstanding that a lot of people have about these species, usually centering around the Lamarckian view that the fish lost their eyes "because they didn't need them any more."  The actual truth of the matter seems to be that if you're in perpetual darkness, using a lot of your energy to produce and maintain a structure as complex and delicate as the eye would be a waste, and diverting those resources to other, more useful purposes is a significant advantage.  It's a subtle point, but an important one.

In any case, this current research turns on two questions -- how cave fish navigate their habitat, and why they have asymmetrical faces -- a curiosity that they share with blind cave crickets.

It turns out that the two questions are related.  The convex side of the fish's skull contains more neuromasts, organs that are not only tactile sensors but give fish information about vibrations and water speed and direction.  All fish have these, but blind fish rely on them to create a mental map of their habitat.  Researchers found that most of the fish have skulls that bend slightly to the left, meaning they're getting tactile input mostly from the right.  And just as you expect, the fish whose skull bends to the left keep their right side in close contact to the walls, and tend to move counterclockwise around their habitat -- and the right-bending fish move the opposite way!

The whole thing brings to mind an article that appeared many years ago in the inimitable science spoof The Journal of Irreproducible Results, describing a little mammal called the Sidehill Gouger that has two short legs on one side and two long legs on the other, so it can stand upright on hillsides.  Thus, like our cave fish, some Sidehill Gougers always travel clockwise, and others counterclockwise.  The article goes into the genetics of the trait, describing how the offspring of a right and a left-handed Gouger produces some of each, but heterozygous individuals end up with diagonally opposite short legs.

They're called "Rockers."

I doubt there's any analog in the cave fish, but it's interesting and more than a little ironic that a piece from JIR actually ended up within hailing distance of reality.


The last story puts to rest the idea that scientists don't know how to have fun.  A couple of mechanical engineers from Boston University, Alexandros Oratis and James Bird, published some research this week in Physical Review Letters describing the physics of shooting a rubber band -- and how to optimize your strategy so it goes straight and doesn't smack your thumb on the way out.

After filming rubber band shooting with an ultra-high-speed camera, what Oratis and Bird found was that when it comes to tension, less is more.  When the rubber band is released, the release of tension in the band zooms forward, and the back end of the band follows, but at a slower speed.  When the tension release reaches your thumb, it allows your thumb to snap forward, dodging the band as it passes.  If you pull too hard, the speed of the tension release is higher, and it's simply too fast for your thumb to duck out of the way.  The result: you give yourself a nice stinging smack.

Wider rubber bands also work better, and for a similar reason; they have a higher tension, so when that's released, your thumb jerks forward more quickly.

Me, I wonder how many times Oratis and Bird popped each other with rubber bands while doing this research.


So there you have it.  Rubber band war strategy, lopsided cave fish, and extremely early flowers.  All of which illustrate what I've claimed all along: science is fun.

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Carl Zimmer has been a science writer for a long time, and his contributions -- mostly on the topic of evolution -- have been featured in National Geographic, Discover, and The New York Times, not to mention appearances on Fresh Air, This American Life, and Radiolab.  He's the author of this week's Skeptophilia book recommendation, which is about the connections between genetics, behavior, and human evolution -- She Has Her Mother's Laugh: The Powers, Perversions, and Potentials of Heredity.

Zimmer's lucid, eloquent style makes this book accessible to the layperson, and he not only looks at the science of genetics but its impact on society -- such as our current infatuation with personal DNA tests such as the ones offered by 23 & Me and Ancestry.  It's a brilliant read, and one in which you'll learn not only about our deep connection to our ancestry, but where humanity might be headed.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]