So – What Happened?

Between 10 and 12,000 years ago, the world changed.  In North America, 35 genera of large mammals became extinct.  Not species, but genera – whole groups of closely related species.  Thirty five genera:  Mammoths, mastodons, giant sloths, horses, saber-toothed cats, the short-faced bear (but not grizzlies), the American lion (but not the Mountain lion), camels (but not llamas and vicunas in South America), the giant beaver, but not the regular little guy.

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So – what happened?  Where’d everybody go?  And why?

For years, paleontologists and archeologists have tried to figure this out.  There have been five main theories to explain this wholesale extinction:

  1. Overkill – to much hunting by the newcomers to North America, the so-called Clovis people;
  2. Environmental change;
  3. Disease;
  4. Some extraterrestrial impact, akin to the comet which is believed to have killed the dinosaurs;
  5. Some combination of any of the above.

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One issue that has come up, because of the paucity of fossil remains, and gaps in the fossil record, is the timing of these extinctions.  Did these genera go extinct at roughly the same time, or were these extinctions staggered, spread out over time? Was this a slow catastrophe, or a fast one?

In 2009, two scientists, J. Tyler Faith and Todd Surovell, took a look at this issue, and published an article titled Synchronous Extinction Of North America’s Pleistocene Mammals, in PNAS, vol. 106, no. 49.  No slouchy journal, either – PNAS means Proceedings of the National Academy of Sciences of the United States of America.

By doing a careful statistic analysis of the fossil remains associated with the extinctions, they concluded that “the combination of these lines of evidence suggests that North American late Pleistocene extinctions are best characterized as a synchronous event.”  Specifically, “our analyses demonstrate that the structure of the chronology of North American late Pleistocene extinctions is consistent with the synchronous extinction of all taxa between 12,000 and 10,000 radiocarbon years. B.P.”

Okay, so what does that mean?

It means that most of these animals all became extinct in a two thousand-year span.  The authors note that:

         “Our simulations do not rule out the possibility that some extinctions may have occurred before 12,000 radiocarbon years B.P. The biogeographic simulation suggests that anywhere from 0 to 8 genera could have disappeared before the terminal Pleistocene . . . Even so, 23–31 genera abruptly disappeared at approximately the same time. Our results leave open the possibility for a small level of background extinctions (0–8 genera) followed by a surge in extinction rates that wiped out the remaining taxa (23–31 genera) between 12,000 and 10,000 radiocarbon years B.P.”

So it is possible, they acknowledge, that of the 35 genera that became extinct, maybe as many as 8 of them had gone extinct earlier that 12,000 years ago.  That still means, however, that 27 of them became extinct in that short – remarkably short – period of time.  As the authors put it,

           “Whether or not background extinctions took place, that a catastrophic event or process occurred at the end of the Pleistocene is abundantly clear.”

The implications for this are important.  Whatever happened, it happened very fast, and was continent-wide.  Europe experienced what the authors call a “long-term, piecemeal extinction process.”  Not so, here.  It happened all across the continent, in what they call “a geologic instant.”

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This conclusion doesn’t necessarily eliminate any of the five possible causes of the mass extinction, but it does put certain constraints on them.  An environmental change, for example, if it was the primary cause of these extinctions, must have been nation-wide and very rapid.  But intriguingly, even those limits – speed and breadth – still fit with three of the possible causes for the extinctions:  “This time period encompasses the earliest secure evidence of human foragers in North America . . . the Younger Dryas cold interval . . . and a possible extraterrestrial impact.”

Well, science marches on.  We still don’t know why these extinctions occurred.  And while two thousand years may be a geologic instant, in the lives of these animals, it encompassed tens or hundreds of generations.  A drought that lasted five hundred years, or seasons so cold that plants wouldn’t grow, could certainly have caused some of these extinctions.  And there may have been a cascade effect, too:  If a given herbivore becomes extinct or vanishingly rare, then the predator that preys on it is in trouble, too.  And family structures may have been disrupted by hunting, too, for that matter:  If the matriarch of the mammoth herd is killed, maybe the young ones don’t know how to survive a particularly harsh winter, or a dry summer.

But as to what happened?  We still don’t really know.  As Faith and Surovell put it, “further research on the biogeographic histories of individual species in relation to detailed paleoclimatic, paleoecological, and archaeological data could help to finally pin down the cause of North American end-Pleistocene extinctions.”

The Giant Sloths – An Unlikely Success Story

Ground sloths were large quadrupedal mammals that were predominantly herbivorous (more on that later).  They evolved in South America, before continental drift had joined North America to South America, and then, managed to cross the land bridge in Central America and make it all the way into North America.  In fact, remains of ground sloths have been found in Alaska.  Not bad for slow-moving, ponderous vegetarians.

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There were many, many species of ground sloths; something like 80 genera, and above that, at least six families.  As you may recall from the last entry; a species is a single type of animal, a genus a grouping of closely related species, and a family a grouping of several different, but related genera.  So ground sloths, although ungainly looking, as will be discussed below, were quite successful – not a fluke, or trick of evolution.  I should note, of course, that there is still some confusion about just which fossil remain of a given sloth falls into which family, and genus.  Nonetheless, the ground sloths, as a whole, were quite successful, and evolved into many different shapes, sizes, and habitats.

Perhaps the best known of the now extinct ground sloths was megalonyx jeffersonii, best known, if it’s known at all, because of its association with President Thomas Jefferson, for whom the species is named.  President Jefferson was an avid naturalist, and paleontologist, who received fossil specimens of the ground sloth that bears his name, in 1796-97.  These included some gigantic claws (of which, more later).  He suggested that they were a species of lion, and suggested that the as-yet undiscovered animal be named megalonyx, or giant claw.  In fact, when Lewis and Clark set out to explore the Louisiana purchase in 1804, Jefferson asked them to look out for megalonyx, which he thought might still be alive somewhere in the unknown west.  He was wrong.  The claws were not from a lion, but from the sloth, and the sloths were extinct.  Nonetheless, his boundless curiosity, and suggestion that discoveries of this sort were worthwhile, remain commendable.

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M. jeffersonii, was enormous – eight to ten feet long.  And it weighed up to 2000 pounds.  Like the other ground sloths, it was herbivorous, and ate leaves, branches and bark it stripped from trees.

Big as it was, however, megalonyx was dwarfed by another giant sloth – Megatherium.  This animal was formidable.  It grew at long at twenty feet, and weighed up to four metric tons.  A metric ton is roughly 2,204 pounds, so an adult megatherium might have weighed almost 9,000 pounds.  You know what else weighs that much?  Elephants.

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Megatherium was confined to South and Central America, but its close cousin, the slightly smaller Eremotherium ranged into southern North America.

I wrote that they were herbivorous, and that is undoubtedly true.  There is some thought, however, that they may also have been opportunistic carnivores, perhaps flipping glyptodonts (think Volkswagen-sized, turtle-shaped mammals) over, to get to their soft underbelly, or even chasing active predators away from kills, in order to scavenge the carcass.  These theories are still quite controversial, and await further testing or discovery for clarification.

These were big, ungainly, slow-moving creatures.  And yet, they thrived.  They walked on all four legs, but could sit upright, to reach up into trees.  Some could stand on their hind legs like bears.  And they were armed with long, sharp claws on their front legs.

They apparently lived in family groups, and presumably the parents would have protected the young.  But it seems unlikely that they were herd animals.

So why are these animals interesting?  There are several reasons:

First, as will be discussed in a later post, when South and North America joined, more animals native to North American spread into South America, than did animals coming north from South America.  Sloths were among the relatively few species that migrated north, out of South America.  Why?

Second, why did they, like so many of the other animals of this time period, become so large?  Presumably, in North America, they were expanding into an otherwise vacant ecological niche, so they had no direct competition.  But they had evolved in South America, where there was competition, and still they grew to enormous size.  Why?

Third – how did they evolve?  They don’t seem like a likely candidate for evolutionary success, these big, slow-moving herbivores.  But they were very successful, for thousands and thousands of years.  Were those claws that deadly?  Did no animal selectively prey upon them?

Finally, as with so many other species of Pleistocene animals, we are left to wonder – what happened to them?  Remains of giant sloths have ben found in association with human hunting – so evidently humans were a species that preyed upon them.  And perhaps, human hunting pressure, combined with a low or slow reproductive rate were sufficient to drive them to extinction.  Climate change, too, may have played a role.  Whatever the reason, they are all gone now – extinct.

But imagine how happy President Jefferson would have been if Lewis and Clark had found a Megalonyx for him.

The Clovis Mission: Ch. 5: Summers

Rain.  Sheets of rain.  Downpour.

 “Ah, shit.”  Lasher spoke. “C’mon, move it!  We gotta get this shit packed up.”   So right away, even before we looked around, the three of us scrambled around and loaded the horses, and saddled the horses, and put on rain clothes, and generally ran around like idiots, until everything was squared away.  Jack was wet, shivering.  And then, of course, the rain stopped.

And I looked around, for the first time, at North America, roughly 12,000 years ago.  You’ve never experienced anything like this.  The air smelled unbelievably fresh and cool.  The sky was clearing and a brisk wind was blowing.  I could see low hills, obscured a little by the mist that was breaking up.  It was cool, morning, early spring.    A couple birds flashed by, but I couldn’t tell what they were.  Bird song – lots of bird song. The country was lightly wooded.  We were still so close to the Mississippi that trees could grow.  The trees were just budding out.  I saw oaks, hickory, a couple willows down in a stream bed near us.

The horses stamped, and a little steam rose from their coats.  Lasher looked around.  We all looked around.  Jack trotted around us, head down, sniffing avidly.  I found I was grinning. Devereaux laughed a little.  Even Lasher smiled.  After a minute or two, Lasher said “All right, let’s get going.”  So we mounted up and set off. 

The first night, we built a small fire, and set up camp for the first time, on a low rise, in a grove of oaks. And started talking. Lasher did, anyway.  He sat there, drinking tea, and asked me, “So, what are we up against?”  I turned.  “What are we likely to encounter out here?” he said.  “I’ve read some about the Pleistocene, but I’d like to hear what you can tell us.  Hey, Devereaux – listen up!”  Devereaux had been futzing around with one of his rifles, but he stopped, and came over to where we were sitting.

“Well,” I said, “that’s really the sixty-four thousand dollar question, isn’t it?  No-one really knows.  I mean, we have fossil evidence of all kinds of animals, most of whom are now extinct  – extinct in our time, that is.  But there’s tons of stuff we don’t know. “

“What kind of animals?”

“Lots.  Lions, bigger than African lions; bison – like superbison – bigger than today’s.  Camels, horses, cheetahs, hyenas, sloths. Saber toothed cats; a giant bear – the short-faced bear – probably the biggest land predator alive in this time.  Mammoths.”

“Jesus Christ,” Devereaux said.  “It’s the American Serengeti.”

“Yeah, and other animals, too. Only, we don’t know nearly enough about them – how many there were; how they lived, how they hunted.  Almost nothing.  That’s one thing Carver was back here studying.”

“Yeah, or why they went extinct.” Lasher said.

“That’s right – we don’t know why that was. “

“Maybe the cavemen wiped them out,” Devereaux said.

“Well, they weren’t really cavemen,” I said. “The people of what we call the Clovis culture were some of the earliest settlers in North America.  We’ve found their stone points, sometimes associated with the skeletons of mammoths.  But again there is still a lot we don’t know.  Where’d they come from?  When?  How?  How did they live?  Where?  How many were there?  This stuff, too, Carver was supposed to be researching.”

“Okay,” Lasher said “Big animals, and lots of ‘em.  How will they react when they see people?  Do we have to worry about ‘lions and tigers and bears oh my?’”

“Yeah, and what about the natives,” Devereaux asked.  “They gonna sneak up on us?”

“Man, I don’t know,” I said. “The people would probably be curious about us, but how that would play out, I don’t know.”

“They better not fuck with us,” Devereaux said.  Christ!  All of a sudden he was a tough guy.

“Look,” I said, “they’re not cavemen.  They’re homo sapiens, just like us.  Modern humans.  As smart as we are, and presumably well adapted to living out here.  We can’t just kill them.”

“No-one’s talking about killing them, right Devereaux?” Lasher said.  “But what about the animals?  Wolf packs, or lions or what have you?”

“I honestly don’t know,” I said.  “This country is so lightly populated that most of the animals, the predators will never have seen people before.  They’d have no reason to fear us.  But we won’t be familiar to them either, so I don’t think they’ll regard us as prey.”

“Yeah,” Lasher said, “but they’re top of the line – apex predators.  They’d have no reason to fear us, right?  But maybe they’re curious.  Or really hungry.  Maybe we look like easy meals to them.  And didn’t you say there were horses here, now?  I’ll bet they’ve seen horses before, and think they’re tasty as hell.”  He stood up.  “So what I think is, we’d better be careful.  I think we’ll take watches, tonight and every night.  Wear the night vision goggles, and keep a sharp eye out. “

That actually seemed like a good idea.  All of a sudden I had visions of packs of huge dire wolves slowly sneaking up and surrounding us.   Just meat for the ravenous.

Nothing happened that night.  We took watches, and it was weird, I can tell you, sitting there, in the absolute darkness, the fire died down to only embers, no ambient light.  The stars looked low, close to the earth, brilliant, like a flung pitcher of milk.  A few clouds, scudding across the sky.  The sliver of the moon rose late. 

I heard coyotes yelping, and then, farther off, wolves. A pack, howling.  That wild and alien sound was haunting.  Jack stiffened, and I thought that he was going to chime in with their chorus. But then I heard the hoarse coughing roar of lion.  A lion!  That’s when I knew, I mean really knew, that we were someplace entirely other, some place and time wholly different from our own.  The horses stamped, restlessly, with some atavistic sense that that wild sound meant danger.  Jack’s ears pricked up, and he growled once, low in his throat.  I called him over, and he flopped down next to me, and I petted him for a while.  Just before dawn, a fox came snooping around the edges of our camp, but our scent was unfamiliar, and it didn’t come into the camp.

Dawn, clear and quite cool.  The sky at first a light, pale blue. The birdsong was loud.    Larks, thrushes, robins. Skeins of geese and other waterfowl, flying north.  Because it was, really, our first day, we celebrated at breakfast with some of the precious store of coffee we had brought with us. 

It didn’t take long to establish our routine, even though there wasn’t, really, any routine, at all.  What I mean is, we’d set out early in the morning, making our way west and a little south, stop briefly at midday, then ride on until evening, when we’d set up our camp.  But there was no routine, really, because of the terrain.  The ground here, in what would later be Missouri and eastern Kansas was rough, wild, unfamiliar.  Deadfalls, streams, rocky outcroppings – everything had to be climbed over or around.  Jack loped around, walking, trotting, sniffing the air, of course, but we kept him close to us – didn’t let him range out in front, the way he had when he’d hiked together back home.  In the mornings, before we mounted up, and at lunch, and then again, in the evenings, I’d work with him, reinforcing our bond, and improving his training.

We passed through the some light woods, and had to stop when a small herd of woods bison came through.  They seemed enormous, dark chocolate-brown, moving sedately, silently past.  Totally unafraid of us.  One bull snorted a little as he passed.  And then gone, like a dream.  Strange that animals that large could move so quietly.  No calves, yet, probably too early in the year.  I grabbed Jack’s collar, out of habit; and then decided to try an experiment.  So I let him go, and simply said “stay.”  And he stayed.  Oh, he looked at the bison as they passed, and sniffed them, and crouched down in that way that border collies have – but he stayed.

After several days of travel, the woods thinned, and the country became more savannah–like. It was our third day, when we first saw them – Mammoths.  A group of them.  The matriarch leading them, then several cows with calves.  Browsing leisurely through the trees.  They were enormous.  Brown hair, coming off in patches, chunks, streamers.  Grumbling, rumbling noises as they moved, with that slow, ponderous, implacable gait.  They seemed out-of-place.  They were out-of-place – better adapted to steppe country than to the savannah that surrounded us.  Their huge tusks were better suited to sweeping snow off covered ground, and their thick shaggy pelts were hardly necessary, at this time of year, in this climate.  Why they were this far south, I didn’t know.  They continued to browse, moving in a generally northeast direction.  I watched them for what seemed like hours, until they disappeared.  Even Devereaux seemed moved.  Until I heard him say, “Jesus, what a trophy that’d make.” 

 

The Clovis Mission: Ch. 4: Summers

 

Despite the very high regard I had for Leonard Carver, I thought he’d been remarkably foolhardy in the way he’d gone back.  It had been planned only as a brief scouting expedition, a chance for him to examine the countryside, in preparation for the summer’s fieldwork.  The summer project was to have involved his grad students and was going to last for six weeks.  But for this scouting expedition, he’d gone back alone, for a four-day look-see.  I thought that was stupid.  You don’t go into unfamiliar country, one swarming with big predators, alone, even if it’s only for a few days.  I still don’t know exactly how that came about.  Maybe because he was so well-known he could just do whatever he wanted.  But as a result, he was all alone back there – disastrous if anything went wrong, as it apparently had.  And, while we obviously knew exactly where he inserted, we didn’t know where or how far he’d wandered after jumping back in time.  And one man, alone, leaves a tiny footprint in a huge country.  So finding him might take us some time.

We prepared for the mission and trained for three weeks.  We trained in Englewood, Colorado.  White and Kramer didn’t stay there with me.  They  dropped me off, said that they’d take care of all of my personal and financial business while I was gone.  They were pretty nice, all things considered; shook my hand, petted Jack, wished me well.

The training center was fairly spartan, up at about 7,000 feet.  I was the first one into the training center.  On the second day, Dr. Steven Devereaux joined me as the second member of the team.  A specialist in the modeling and mechanics of the time travel apparatus, the technician who’d find out what had happened to the ASU site, and, hopefully, fix it.  He was a couple of years younger than me, thirty-two, I think.  Fairly slender, short dark hair.  Nerdy.  About what you’d expect from a techno-math-physicist.

Some of our training was academic – reviewing the maps we’d be bringing with us, learning how to send the time beacons.  Which, by the way, was easy, simple.  Food identification and preparation.

At night, we had to sleep with these mesh coverings over our head.  Neuro-linguistic programming, they told us.  Guaranteed, they said, to vastly accelerate the speed with which we’d pick up a new language.   It worked by electromagnetic stimulation of the speech centers in the brain.  I supposed it was in case we ran into any of the people living back there, back then, although I thought it was unlikely.  And, as far as I could tell, other than being slightly uncomfortable, the mesh headpiece and the neuro-linguistic training had absolutely no discernible effect.

For the most part, the training was – how shall I put this?  Stupid.  The firearms training was informative, and, somewhat to my surprise, fun.  Skinning and butchering animals, less so.  Otherwise, camping skills?  I already knew how to camp.  Saddling and unsaddling – I mean, c’mon, how long does that take to learn?  Not three weeks, that’s for damn sure.  Setting and sending the time beacons?  Easy.  Water purification?  Child’s play.  So why were we spending three weeks in “training?”

I thought, after they had pushed me so hard to decide instantly, that this delay was madness.  It made no sense to me.  If they were in such an all-fired hurry to get me committed, then why a three-week delay before sending us back?  Gene Kessler was the official in charge of the program, and I asked him about this after the third day.  He told me that this delay was only an “apparent” delay.  We would be sent back to three months before  Carver disappeared.  This, it was thought, would give us time to travel from St. Louis, to the Arizona State site, where Carver had last been, in time to find out what happened.

Time and distance.  We had a one-way journey of about 1400 miles, at a minimum.  But that was little more than a rough estimate, insofar as there were no roads, and we’d have to travel across entirely wild country.  We’d be at the mercy of the terrain, and would, I supposed, have to detour hither and yon to get there.  The team at DARPA figured that we’d average maybe twenty miles a day.  Sometimes more, of course, sometimes less, but they thought twenty miles/day was a reasonable estimate, for purposes of their time and distance calculations.  So, what? About two and half months to get there.  And a couple of weeks of “spare” time.

I knew a little about camping.  Devereaux had known nothing.  For Steven, the training was much more useful.  He’d never been camping, never ridden a horse, knew nothing about wilderness living. Not a clue about the guns.  An absolute wizard with the time beacons, though.  A very pleasant guy, I thought.  And a quick learner. He got the hang of everything pretty easily.

Lasher was a different story.  He didn’t show up until the middle of the second week.  Kessler had told us only that Lasher was Special Forces; long-range recon.  He apparently was going to be our security.   Tall, slim, dark hair, calm green eyes that missed nothing; an easy smooth walk; I had the sense that Lasher did everything gracefully, efficiently.  He looked very fit and very alert, and he was.  He didn’t say much.  He was a little older than me – probably late thirties, early forties.  No hint of a smile.  Two day old stubble.  Scruffy clothes.  A professional, I thought.  He gave off that calm, serious “Do not fuck with me” vibe.

Obviously, based on what Kessler had told us, Lasher didn’t need any training.  In fact, what he did was take over our training.  He coached us on our marksmanship, with all three weapons –rifle, shotgun, pistol.  He was surprisingly patient, and, it turned out, very good at teaching, at explaining to Devereaux and me what we were doing wrong.  And in a couple days, both of us were shooting much better.  Not marksmen, by any means, but we were at least respectable.

He also taught us about what was called the field protocol.  Basically, it was how to be alert in unfamiliar territory, how to move as a unit, how to use hand signals, all the stuff you’d want in a hostile environment, in enemy territory, or something.  I tried to explain to Lasher that we weren’t going into enemy territory.  Clovis fossils and artifacts were rare, ergo, the people known who made the Clovis points were thin on the ground.  Scarce.  Most of North America was uninhabited.  No people.  For all practical purposes, we’d be the only ones out there. We’d be unlikely to even see anybody.  And, even if we did, they’d have spears, and atlatls; we’d have rifles.  They’d have flint knives; we’d have pistols and Damascus steel knives.

Lasher just looked at me.  After a long minute, he said, “Yeah, well, we’re going to do it my way, anyway.”  That was it.  No discussion, no debate.  Just a given.

“Look, I don’t mind doing whatever,” I said. “I just don’t see why this is such a big deal to you.  There’s not going to be anyone out there, and even if there is, we outgun them by a mile.”

“I believe that is what Custer said,” Lasher replied.  And he sort of half-smiled.  I guess that was what he thought was a joke.  So Devereaux and I trained on, and learned the field protocol.

The biggest surprise was Jack.  He was a border collie mix, four years old, about.  I’d got him as a rescue puppy, and had sort of trained him, in a half-assed way.  What a great dog.  He was so smart, and full of energy.  I loved him.  And so, it turned out, did Lasher.  I saw him holding Jack’s head, and grabbing his fur, and talking to him.  So I was stunned when Lasher said “Too bad about Jack.  He’s a great dog.  But he’s not coming with us.”

“What?”

“Your dog, Jack.  He isn’t coming with us.  He’s a liability.  We can’t take him along.”

“Bullshit,” I said.  “Let’s go see Kessler.”  Lasher nodded, and he and I and Jack went into the field office to talk to Kessler.

I told him, “Look, Lasher just said that I can’t bring my dog with me.  You’ve got to talk to him.”

Lasher said, “The dog can’t come.  He isn’t trained.  He’ll spook the game.  He can’t be relied on.  We can’t bring him.”

“I see,” said Kessler.  “Well, Jeff,” he said, he said to me, “it seems to me that Mr. Lasher makes some very valid points.  I’m sure we can find someone to care for your dog while you’re gone.”

So, really, what did I think Kessler was going to do?  Referee?  Help us work it out?  What he did was, he sided with Lasher.  Of course he would.  Like he’d oppose what the security man said.

I drew on my extensive education, my doctorate, my scholarly research.  “Fuck you,” I said.  “If Jack isn’t going, then I’m not going, either.  I don’t’ care what you two have to do, but understand this – Jack goes where I go.  If he’s out, I’m out.”

I was beyond angry.  I was furious. The intensity of my rage surprised me, and even as I was swearing, part of me was watching, mortified.  He was it – other than my mom, he was the only family I had. We’d hiked for miles through the mountains and hills near my home.  He’d come with me on my fieldwork in the Green River country in Wyoming.  He’d hang out in my office on campus, while I taught class.  He was my companion.  So even though I was mortified, I was real damn serious.  I would not leave him.  Not in some kennel.  Not for four months.  Not at all.

“Look,” I said.  “He’s a border collie.  They’ve been bred to work with animals, to be partners with men.  Can’t we train him, so that he’ll work with us, not scare any animals away?”

Lasher just looked me.  Then, after a minute, he said, “Okay, we got a week.  If we can get him trained, I mean really trained, then the dog can come.  But if we don’t, if he isn’t perfect, then he isn’t coming.  And then you’ll have to do what you have to do.”  And then he left.

Kessler sighed.  “That’s Lasher.  Jesus.”

So, for the next 8 days, Lasher trained Jack and me.  He was like the freaking dog whisperer.  He had Jack trained unbelievably.  Come, go, stay, heel, go left, go right, come up; all the things that border collies are supposed to do.  And he had me trained, too. “He’s your dog, he told me, “He’s got to listen to you.   So here’s what you do.”  Over and over.  Until, at the end of that week, I got it.  I understood what he was talking about, and finally, Jack and I “clicked.”  We were a team.

And Sunday night, Lasher looked at me and Devereaux and Jack and said “That’s it. We’re ready.  We’ll go in tomorrow.”

What we brought:

Twelve  Horses.  A horse for each of us to ride, a spare horse for each of us (a “remount,” as the cavalry has it); two horses for Dr. Carver; three pack-horses; and a spare pack-horse.  The reliance on the horses was our greatest worry.  We were embarking on a round trip of approximately three thousand miles – as the crow flies.  And we were certainly not going to be able to travel that directly.  In all likelihood, we’d end up travelling well over three thousand miles.  The distance alone is an enormous burden for any animal. And this was travel in wilderness.  We’d be confronting all of the perils of the trip –deadfalls,  river crossings, animal attacks.  So we all thought that we were taking too few horses.  We had discussed this at length in the preparation sessions with the DARPA representatives, and Dr. Kessler.  Unfortunately, none of us saw any way around it. Kessler and the techs thought we might be able to take two, maybe three more horses than we did.  But then, paradoxically, we thought that to take more would make the size of the remuda unwieldy.  So we were stuck.  Twelve horses it was.

Oddly, Lasher seemed the least concerned about this.  “We can walk if we have to,” he said.  “And if Devereaux can get the ASU station up and running, we can just come back that way.”  Maybe we’d only go out by horse, but come back by. . . . magic.  (I still, even after all this time, can’t write “we’d come back by ‘time travel’” with a straight face.  It sounds like something out of Star Trek).  So, in the end, it was twelve horses.

What else?  Two of almost everything.  Two rifles each, two shotguns each, three pistols each.  (Lasher took four).  Clothes for all kinds of weather and temperature. Tents, sleeping bags, water filters.  This was somewhat controversial.  I argued that since we were going back before the modern era, i.e. before pollution, that there’d be no need to filter the water.  After all, the indigenous people  didn’t have micropore filters.

“Ever hear of Giardia?” Lasher asked.   So we took the filters.

We took a first aid kit – much bigger and more extensive than I had previously seen.  Lasher had  some training as a field medic, and Devereaux, it turned out, was an EMT.

We brought lots of gear: Pots, pans, salt, coffee, sugar.  Field guides to birds, to plants, to trees, to mushrooms.  I was the nature guide on this expedition; the one who was supposed to know what was safe to eat; how to traverse the varied ecosystems we’d encounter; how to deal with the natives, in the unlikely event that we met any; stuff like that.  And I thought the field guides would be useful.  From an evolutionary standpoint, twelve thousand years ago isn’t very long at all.  So the oaks and aspens, the fungi and mushrooms we’d see would be the same as the ones living today.  Stranger, though, to think about the animal population back then.  All the animals we know today – raccoons, robins, deer, ducks – all of them – were living there, back then.  But so were all kinds of other animals.  Animals no-one alive today has seen.  Mammoths, mastodons, giant sloths.  Passenger pigeons.  They’re all extinct now.  So it was quite a juxtaposition – bringing a field guide to birds, while worrying about running into a saber-toothed cat.

So what else? Packages and packages of freeze-dried foods.  They took up almost no space, to offset the fact that they had almost no taste.  Binoculars, axes, saws, knives. Dynamite.   Rope.  Needles and thread.  Lighters.  Matches. Traps.  Mirrors (for signaling).  Spare horseshoes, files, and nails.  More stuff than I had ever thought about.    Devereaux’s gear – the stuff he was going to use to repair the tesseract, if possible.

It seemed like a lot.  It was a lot.  But even as we practiced packing it on the pack-horses, I knew, I just knew, that it wouldn’t be enough.  Or rather, that we’d need something we didn’t have.  That was the first time, really, that the enormity of what we were doing hit me.  We’d be truly on our own.  I wondered how the mountain men had done it.  What if . . . What if . . .?  No doctor, no hospital, no cavalry to ride to the rescue.  It was a daunting task, and for the first time, I really knew it.

Personal stuff:  I brought pens, pencils, and paper;  several digital cameras and lots and lots of chips; a video camera; a magnifying glass. Here’s what I desperately wanted to bring, but couldn’t:  A complete dissection kit; a CT scanner; three hundred gallons of formaldehyde; five hundred pounds of plaster of paris; a cryogenics lab; a gene sequencer; 500 radio collars; six hundred tranquilizer darts, a gas chronometer; an ultra light aircraft for aerial surveys, and a tractor-trailer to haul it all in.

I brought Give your Heart to the Hawks, by Win Blevins, a book about the exploits of the mountain men.  I commend that book to anyone who is going off into the wilderness.   Devereaux, as it turned out, brought about two pounds of weed, and a bong, and rolling papers.  That was a surprise.  Lasher brought a big long, flat box, and  square (cubical) box, about 12 inches on a side.  And packs and packs of gum.

And so, off we went.

The insertion took place at the ground floor lab at Washington University.  The array was complex, to say the least, and I was surprised at the number of technicians running around, placing sensors here, and moving cables there.  The three of us, Jack, the horses, and all of our gear were placed in the center of the array, inside the tesseract.  We all had to go at the same time, because the vagaries of the insertion were such that successive “drops” might not land in exactly the same time.  That, I gather, was part of the reason why something as big as a plane or helicopter couldn’t have been used.

Kessler came up and shook hands with each of us, and wished us good luck.  And then, (and I loved him for it), he stooped and petted Jack.

And then he left, and we stood around for about three more minutes, while they calibrated whatever it was that needed calibrating, and then they counted backwards. Five.  Four.  Three . Two.  One.

Blink.

Transcendence.

Rest.

Stop.

Taxonomy: This Will Be on the Final

Taxonomy –

Today we have to go deep into the weeds, to understand the first of several scientific concepts that are going to be necessary to understanding the Pleistocene ecosystem.

That scientific concept is taxonomy, a system for sorting and classifying things, such as animals.

The issue, I suppose, is how to we organize our views of nature.  We see that there is physical resemblance between cats and lions, or tigers.  What, if any, is the relationship between them?  Between a horse and a rhinoceros?  A dragonfly and a bee?

Once you starting thinking about evolution, about one species evolving out of another, then you naturally start considering the relationships between the various species, and groups of species.

Taxonomy is one way to approach that organizational impulse, one way to attempt to delineate the relationship between various animals and between various types of animals.

Taxonomy means “the grouping or categorizing of things into an outline or tree structure.”[1]  It’s used for all kinds of biological sciences.  There are several kinds or systems of taxonomy, but the two best known are “scientific classification,” which grew out of, and is derived from Linnaean taxonomy, and “cladistics.”

Today we’re going to take up scientific classification.  We’ll save cladistics for another time.

First an overview, then on to the details.

Overview:

Every animal (we’re not going to consider plants right now) can be identified, or labeled, as it were, within the system of scientific classification.  There are seven levels which range from the most narrow, specific category – species; to the most broad – (animal) kingdom. Every animal is assigned to some label at each of the seven levels.

Starting with the broadest category, and going to the most specific, the categories are: Kingdom

Phylum

Class

Order

Family

Genus

Species

 

It’s a hierarchy.  Species is the most specific category; Kingdom the most general.

This system of taxonomy is a way of evaluating diversity of animals through time.  That is, if you go all the way back to the very beginning, there was the first member of the animal kingdom – probably a blob of protoplasm.  From there, it divided, and evolved and over eons and millions of years, different types of animals arose.  Taxonomy is a system for sorting through those different types of animals, in order to see their relationship with one another.   And the hierarchical system is sort of a time machine.  Species is the last, most recent type of a given animal; genus is the name for a group of closely related animals that evolved from a common ancestor; family is older and earlier still.

Say you’ve got a cat, an ordinary house cat.   That cat would be identified, taxonomically as

Kingdom:       Animalia

Phylum:         Chordata

Class:              Mammalia

Order:             Carnivora

Family:           Felidae

Genus:            Felis

Species:          F. catus

Taxonomy, then, is a way of organizing our thinking about how animals relate to one another.   As we will see, however,  these categories – Family, Class, Phylum, etc. are imprecise, and imperfect.  For example, when we talk about what is a species, down below, you’ll see that while there is a general idea of what a species is, there are also exceptions to the rule, and cases where the label is useful, but not strictly accurate.  Still this taxonomic system has been a useful tool for decades, so it’s worth taking a look at.

So, lets’ start at the bottom, at a level even below species – “Breed.”

What is a breed?  A breed is a type within a species.  Dogs are the easiest to use as examples.  There are lots of breeds of dogs, right?  Pomeranians to Great Danes.  Each breed had been developed to have certain consistent characteristics – shape, type of fur, behavior.  And when mated with another of the same breed, the offspring will have those same characteristics, too.  Animals of the same breed demonstrate homogenous behavior, and have a homogenous appearance – but only within the breed.  That is why all standard poodles look and act so poodle-y, and not at all like bulldogs.

But breeds are (a) only applicable to domesticated animals; and (b) are still the same species of animals.  All dogs, whatever their breed, are still dogs.  That means that they are still the same species; and capable of mating with any other dog, and having viable, fertile offspring.  That is where mutts come from.

So “breed” is a concept of types of domesticated animals within a single species.

Species.

A species is a group of animals which can interbreed with another animal of the same type, and have fertile offspring.  For the most part, an animal of one species cannot, and probably will not, mate with an animals of a different species.  And animals of one species cannot produce fertile offspring with animals of another species. Thus, for example, porcupines mate only with other porcupines, and have baby porcupines, called, by the way, “porcupets.” Really.   And crows mate with crows.

Crows don’t mate with porcupines, or with seagulls, for that matter; and porcupines don’t mate with skunks.  So, in very broad general terms, these concepts underlying the term species, work fairly well.

But there are exceptions to this rule, or, more specifically, cases where the term species doesn’t have the neat classical boundaries associated with the concept of speciation.

First, occasionally animals of different species do breed with one another, even though they “shouldn’t.”  Recently a grizzly bear-polar bear hybrid was shot and killed in northern Canada.  And even though they’re different species, horses can and do mate with asses, and produce offspring.  So, since people knew that (sometimes, some) different species could nonetheless interbreed, the idea of species was modified to incorporate the idea that even if different species interbred – say a horse and an ass – the offspring would be sterile.  So another test of defining a species was whether its offspring were fertile.  As long as the offspring – the jackass – was sterile, the concept of species was okay.

But even that caveat is not watertight.  Although wolves and coyotes are considered to be different species, they do mate and reproduce, and have fertile offspring.  And lions don’t normally breed with tigers.  But they can, and can produce hybrid offspring:  Ligers or tigons.  Now, in fact, this doesn’t happen outside of zoos (partly because outside of one small area in India, the ranges of lions and tigers don’t overlap; and partly because lions and tigers preferentially seek out their own kind to mate with).  But sometimes, rarely, hybrid offspring –ligons, say –are fertile.

These situations – fertile wolf-coyote hybrids; fertile ligers seem to cause the clean definition of species to break down.

Moreover, it is not always easy to know whether a given animal fits within an already defined species, or should be assigned to a new species.  This can be particularly difficult given the normal variation of animals within a given species – regional differences in coloration, for example.  Likewise, the line between two closely related species can sometimes be blurry.

So the notion of a species is neither perfectly clear, nor perfectly simple. Species is a concept that kind of works, but has lots of holes.

And yet – the idea does work, pretty well.  We can tell a robin from a blue jay, a skunk from a badger, an Indian elephant from an African elephant.

So while the idea of species isn’t perfect, it’s what we’ve got.  It means the same kind of animals, breeding only with the same kind of animal, and producing viable, fertile offspring.  Crows mate with crows, and have baby crows.  Same thing with porcupines, or killer whales.

Moving up the hierarchy, we come  to “genus.[2]

Genus comes into play when you see animals that are kind of like one another, but different, too.  Different kinds of giraffes, say, or seagulls.  They all look kind of similar, but there are enough differences so that it’s clear that they’re not the same.

That’s where genus comes in.

A genus is a group of closely related, quite similar species of animals.  So, for example, a house cat, is in the genus felis, together with other, small, closely related species of cats, such as the jungle cat, the black-footed cat, and the sand cat.[3]  There are lots of animals which have a common name, even though they may fall within different species.  So we might say, “oh look, there’s a sparrow,” even though there are a number of different species of sparrow.[4]  We’d say, “watch out – There’s a skunk,” even though there are different species of skunks.  So we use the name “sparrow” or “skunk” generically.  And that, kind of, is the concept of genus.

800px-Striped_Skunk

Oh hey – a skunk!

 

They all look pretty similar, and its not too hard to imagine that they all shared a common ancestor not too long ago.  So they’re different species; live in different habitats; have different habits, maybe; and don’t interbreed with one another.  But they’re close.

An inherent notion here, although it’s oversimplified, is that members of the same genus evolved from a common ancestor, not so long ago.  That is, as we will see below, members of the same family may have evolved from a common ancestor, too, but the various family members diverged from that common ancestor earlier, before the members of a genus diverged from each other to make new species.

But then, what about similar animals, which are nonetheless still a little more different?  A leopard, say, compared to your house cat.  They’re both clearly cats, right?  And yet, different size, different habitats, different behaviors.  Leopards are in a different genus:  panthera, along with the lion, tiger, and jaguar.  And what about the puma, also called the cougar or mountain lion, you might well ask? Nope, neither felis, nor panthera, but its own genus (along with the jaguarundi) – puma.

The Lynx and the Bobcat are in the genus lynx.

This is where the next level of taxonomical sorting comes in – the “Family.”

This is the level for clustering animals that are somewhat similar, but also quite different from one another.  The idea is that they have all descended from some earlier ancestor, and there are still some anatomic similarities in their skeletal structures, but over long periods of time have adapted to very different conditions, have developed different features, and in short, are not as closely related to each other as members of the same genus are.  A family is a cluster of genera.

So even though house cats are in a different genus than leopards, they’re all still in the same family – felidae.

yeah, this shouldn't happen.

 

 

yeah, so this shouldn’t happen.

 

 

And if you think of clumping related groups (genera) together, it makes sense. Of course all cats – from house cats to lions – belong in the cat family.  Dogs, wolves and foxes – sure, lump ‘em all into the dog family.  Bears are bears.  All tapirs are in the tapir family.

The level, moving up, is “Order.”

This is where animals that are still more distantly related to one another are clustered, based on some similarities.

An order is a group or cluster of families.  For example, the order Carnivora, includes the cats (from lions and tigers on down); dogs (and wolves and foxes); bears (all of them); hyenas; minks; raccoons; civets; and pandas; walruses and seals.  The word Carnivore – meat-eater – is the basis for this order.

The idea, apparently, is that these types of animals, while certainly different, nonetheless have some things in common, derived from a common ancestor long, long ago; so that scientists can lump them together.  In the order carnivora, for example, these are all predators, meat-eaters.

But right away, you can see the problem:  Some of the animals on here – pandas, for example – are in this order, but they almost exclusively vegetarian, subsisting mostly on bamboo.  And some mammals which are carnivorous – orcas, for example – are not in this order.  So, what gives?

There are a couple answers to this question:

  1. It’s not a very good system.  And, in fact, there are lots of differing approaches to how best sort and organize animals in relation to one another.
  1. It is based on organizational underpinnings from the past, when it was the only system of organizing.
  1. It depends on what any given taxonomist says, although some conventions are so well –established that they aren’t going to change. (But that’s not always true for newly discovered animals).
  1. There are underlying anatomic similarities between the families of animals which comprise an order, so that it seems reasonable to lump them together.  For example, the horse family, the rhinoceros family and the tapir family are lumped together in the order Perissodactyla, because they have an odd number of toes on each foot (one or three; and remember, horses evolved from earlier species that had more than one toe, per foot).  So, even thought they are otherwise dissimilar, horses, rhinos and tapirs have this foot anatomy in common, and so are lumped together.

And the teeth and skeletal structure of pandas are so like that of bears that they seem to fit in here, even if they have evolved to have a different diet.

And killer whales’ anatomy is so different that even though they have evolved to eat meat, too, they don’t fit here.

There are lots of orders, just within the class of mammals:

•          Order Artiodactyla (even-toed ungulates: antelope, deer, camels, pigs, cows, sheep, hippos, etc.)

•          Order Carnivora (carnivores: cats, bears [like the panda, polar bear, grizzly, etc.], weasels, pinnipeds, etc.)

•          Order Cetacea (whales, dolphins)

•          Order Chiroptera (bats)

•          Order Insectivora (insect-eaters: hedgehogs, moles, shrews)

•          Order Lagomorpha (rabbits, hares, pikas)

•          Order Macroscelidea (elephant shrews)

•          Order Perissodactyla (odd-toed ungulates: horses, rhinos, tapirs)

•          Order Pholidota (the pangolin)

•          Order Primates (apes, monkeys, lemurs, people)

•          Order Proboscidea (elephants, mammoths, mastodonts, etc.)

•          Order Rodentia (rodents: rats, mice, squirrels, gerbils, hamsters, etc.)

•          Order Sirenia (sea cows, manatees)

•          Order Tubulidentata (aardvarks)

•          Order Edentata [also called Xenarthra] (sloths, armadillos)

•          Order Hyracoidea (hyraxes)

And these are just the orders for placental mammals.[5]  There are orders for birds, reptiles, insects, fish and amphibians, too.  Many, many orders.

“Class” is the taxonomic level where big differences, and these vast numbers of species, genera, families and orders are simplified.  What I mean is that there are (or were, under traditional systems of scientific classification) only seven classes, in which to sort any given animal.  They are:

Class Agnatha (jawless fishes)

Class Chondrichthyes (cartilaginous fishes)

Class Osteichthyes (bony fishes)

Class Amphibia (amphibians)

Class Reptilia(reptiles)

Class Aves (birds)

Class Mammalia(mammals)

Now, obviously, before assigning an animal to one of these classes, you’d need to know the definition of each class.  What exactly is an amphibian, or a mammal?  But – once you have those definitions, you can match your animal up to the list, and see which one of these seven classes it belongs to.  Here, we don’t care which species, or genus, or order the animal is – we’re just sorting it into one of these big classes.

We can spend endless amounts of time worrying out the precise, persnickety definitions of each class, but screw it – we’ve got better things to do.  So let’s not waste time.  Here’s the quick and dirty:

If it’s a fish and it has bones – Osteichthyes

If it’s a shark – Chondrichthyes

Frogs, toads, salamanders –  Amphibia

Feathers –  Aves (Birds)

Snakes, lizards, crocs, gators – Reptilia

Fur, milk – mammalia  – Mammals.

If it’s a fish and it has no jaw, it’s gross and disgusting – Throw it back and get out of there.

LAMPREY0624_3GD_6393811-600x363

Omigod! Omigod! That’s a freakin’ jawless fish!  Run!

But again, the beauty of this system is that we are still sorting based on common characteristics.  There are lots of different types of fish, but here, we put them all into the same class, so long as they have bones.  Same thing with mammals or birds.

Okay, onto “Phylum.”

Phylum, the level of classification below Kingdom, is simultaneously easy, and devilishly difficult to pin down.  There is a lot of disagreement about just what, exactly, phylum means, and how many phyla there are.  We, however, are going to take the simple, straightforward route to understanding phylum.  For our purposes, it is a system of classifying animals based on common bodily attributes, and to make it even easier, there are only two phyla we need to be concerned with, here at Pleistoscenery: Insects, and everything else.

Insects are in the phylum arthropoda –they have segmented legs, and exoskeletons.

Everything else, for our purposes, means all the fish, birds, amphibians, reptiles, and mammals.

And what makes all those different kinds of animals –  fish, birds, amphibians, reptiles, and mammals – fit into the same phylum?  Answer:  They all have spinal cords.  And, indeed, the phylum is called chordata – animals with central nervous systems, and spinal cords.

Overall there are something like 35 phyla.  But the reason we’re going to skip them is because they mostly consist of various types of mollusks and worms.  And, really, who cares?

The final level in this hierarchy is “Kingdom.”

“Kingdom,” although it seems easy, isn’t quite as simple as you might think.  Sure, it’s easy enough to place a cat in the animal kingdom, instead of the plant kingdom, but what about bacteria?  Fungi?  Where do they fit?

Answer:  They fit into their own kingdoms, but guess what?  We’re going to ignore them.

All you need to know is that every fish, reptile, amphibian, bird, insect and mammal fits into the animal kingdom: Animalia.

This system is far from perfect.  It’s based, to a large extent on what a given taxonomist thinks is the best place to assign an animal.  Some of these scientists are splitters – they think each animals should be in its own genus, and its own species. [6] Others are lumpers – they tend to lump lots of animals into the same genus, the same family, even the same species.

And this process of deciding where taxonomically, an animals fits is even more difficult when it comes to paleontology, when all you’re working with is a partial animal skeleton, in a poor state of preservation.  Or when you only have one or two skeletons – total – to base the decision on.

But the fundamental idea makes sense – new species arise out of older ones, evolving and adapting to changes in the environment.  New anatomic adaptations, new appearances, new behaviors emerge, but they do not simply spring into being – they grow out their earlier ancestors.  So by studying the anatomy and behavior of animals, scientists are able to make informed judgments about the (a) evolution of different species; and (b) the relationships between various species.

Is this system perfect?  Absolutely not.  But it is a useful tool to understand (or to try to understand) the network of life around us.

Okay – we’ve studied taxonomy.  You tell me what this is:

JackalopeHistory2


[2] The plural of genus is genera.

[3] By the way, do yourself a favor and look up the black-footed cat.  Adorable.

[4] In fact, it gets even more confusing, because there are many different genera of sparrows.  So any given sparrow is a member of a species, is in a genus, and in a family.  Thus, the name “sparrow,” doesn’t identify the bird too strictly – all it says it that this bird in the family of sparrows.  Two little brownish birds, both called sparrows, could be different species, and even different genera.  But they’d still be in the same family.

[5] Don’t even get me started on marsupials, or the duck-billed platypus.

[6] I’m not saying that whoever is in charge of sparrows is a splitter, but go take a look at “American Sparrow” over in Wikipedia, and tell me what you think.

The Clovis Mission: Ch. 3: Ross

Metairie, Louisiana.

Ross knew the General; well, the retired general now, Ambrose Maddox.  Forced, ever so delicately, into retirement after reports surfaced about some of his activities in Afghanistan.

And Ross knew about those activities, too.  After all, he had served with Maddox, before he’d been cashiered, along with several of his men.  Over fucking bullshit. Bastards.

No, wait.  Calm down a minute.  Be here now.  Ross regained his equilibrium.

“Thank you for coming, Colonel,” Maddox said. “It’s nice to know I can count on a few good men, when I need them.”

Ross nodded, and said, “Sir.”

“Colonel, we’ve got a situation, and we need your help.”

Ross thought, “We?”

Ross said, “Sir?”

“You know about this time travel thing, right?”

“Yes, Sir.”

“Three stations, right?  Fairbanks, St. Louis, and Arizona, right?”

“Yes, Sir.”

“Well those DARPA pukes been using it for some scientific research into cavemen or some such shit, and now they fucked up.”

“Sir?”

“First, the station at ASU – that’s Arizona State University, Colonel – the station there has gone down.  Deader than Uncle Harry’s Aunt.”

“Sir?”

“Second, they’ve sent a civilian –  a civilian, for Chrissakes! –  back to fix it.  Accompanied by another civilian, some professor of cavemanology or some such shit.  Well, Colonel, the people in the Defense Department, and my friends at NSA do not want some civilian running around out there, or back there, whatever.”

“No Sir,” Ross said.  He knew his lines.  And he knew this story was phony.  Maddox was out – O. U. T. – out.  No fucking way he was tied-in with Defense or NSA.  No.  The story was bullshit.  And obviously bullshit.  He was meant to see through it. So okay, why?

Because this is something else.  This is a black op.  This is the spooky stuff – covert.  Fair enough.

Didn’t matter much.  Ross knew what loyalty meant.  He knew that the General would take care of him – hell, he already had.  He’d run some serious interference protecting Ross and his boys after that last go-round over there.  So, yeah, Ross knew about loyalty.  Whatever the mission, he was in.

“No sir, we don’t want that at all,” Maddox continued. “It’s absolutely critical that we get that station repaired, and prepared – you know the President’s going to go out there to that Arizona station to give a speech, honor the fine men who perfected time travel, let the world know what we done.   And now that very station has gone down?  A little too coincidental, I think.”

“Colonel, we have reason to believe that this station has been brought down by an act of sabotage, and these purported civilians making their way out to Arizona present a clear and present danger to this great land of ours, to our science, to our technology.  These men are traitors.”

“That’s where you come in.  We want you to assemble a small team – no more than eight men.  Your men, Colonel.  We’ll task two scientists to accompany you.  We want you to jump back there, find those traitors, eliminate them, and then proceed to the ASU site, where the two scientists – our scientists –  will get the station up and running.”

Okay, Ross thought, so that’s the cover story – go back and wipe out these traitors.  Got it.  What’s the real story?

“Yes sir,” Ross said.

“We’re also going to send two more of our men with you, Colonel.  Good men.  Treat them with respect.  They are mission critical.”

Ah, this was a clue.  These guys, whoever they were, were part of this op, whatever it was.  Two of “our” men.  Whose men would that be?

“Understood, Sir.”

“We’ll keep working from our end, here.  Maybe we can jury rig a way to get that station fixed from this end.  But your job, Colonel, is to go back and get those two, then proceed to the station in Arizona.

“Yes, Sir,” Ross replied.

“Time is short, Colonel.  I want you to assemble the team within one week.  My aide, Swanson, has all the details.”

“Very good, General,” Ross said.

“That’s all, Colonel,” Maddox said.  “Dismissed.”

Ross had almost made it to the door when Maddox said “One last thing, colonel. Something that might interest you.”

“Sir?”

Those two civilians have some security on their trip.  Someone you know.”

“Sir?”

“Daniel Lasher, Colonel. Master gunnery sergeant Daniel Lasher.”

The Clovis Mission: Ch. 2: Summers

Things started happening real fast.

First, to my amazement, Dean Mendelsohn got out of the helicopter, with luggage.

“I’ll stay and wind things up here, for you,” he said.

The Dean?  Here?  That sly old devil – still wanted to show he could do fieldwork, I guess.  Or maybe this was so urgent that they didn’t have anyone else to come in for me.

But either way, this was happening fast, fast.

Because as he was stepping out of the chopper, they told me to pack up my gear, because I was flying out with them.

So within an hour of their arrival I found myself flying across country with two men from DARPA, heading for training for this mission.

Here’s the thing:  I didn’t know anything about time travel.  I still don’t, really, not the complexities of the math, or the real science behind it.   I’d heard or read that we couldn’t change the past, but that we could learn from it.  In other words, no matter what you or I did 12,000 years ago, wouldn’t matter – we’d end up exactly as we were.   That always seemed a little weird to me, but I didn’t really think about it very much.

And when I did think about it, it was usually to envy someone like Carver, who had had the opportunity to actually go back in time and study the Pleistocene.

So as we flew, White tried to explain time travel to me.

“Let’s start with time travel itself, first, before we talk about the beacons, okay?”

I thought that sounded like a good plan.

“As you know (I hadn’t), the secret to time travel is quantum entanglement – spooky action at a distance.  Turns out it works over time as well as space.”

“But it requires amazingly accurate pinpoint computation, to synchronize this ‘now’ with that ‘then.’  We’re talking about the kind of calculations that make supercomputers seem slow.   It’s so slow and expensive that we’ve only got these three stations up and running, ASU, St. Louis, and Fairbanks.”

“Yes, but how does it actually work?  What happens?”

“Why, from your standpoint, that of the time traveler, it’s easy and painless.  The transmitter, say the one at Washington University, is a big box.  They call it a tesseract – it’s a multi-dimensional cube.  They build a smaller one inside it, and that is sent back to the time you’re aiming at.  Then, you and your companions and your gear stand within the main tesseract, it does quantum scanning, and transmits you to the slightly smaller tesseract which has been prepositioned at the time you wish to visit.”

“Wait – it transmits me?  How?  Am I de-materialized?  What?”

This started sounding a little scary.

“No, not at all.  ‘Transmits’ is just the term we use for the process.  What happens is that the quantum field set up within the tesseract substitutes the previously chosen time for the present.  That is the variable that changes.  You are within the field, and the three physical dimensions –- length, height, width, you know  —  remain the same, but the fourth dimension –  time – is switched.  That’s the math part that we’ve been talking about.”

“Yeah, right, spooky action at a distance.  Got it.  But it’s safe, you say?”

“Oh yes.  You stand there, or sit, for that matter, while you’re scanned, and then the tesseract changes the one variable – the time in which you exist – substitutes the past for the present.

“And that’s it?”

“Yes, that’s it.  You feel a flash or some people have described at as a twitch, or a tingle, and look around, and you’ll see that instead of being in the lab at Wash. U., you’re back sometime in the past – whatever time you’ve picked.”

And, he explained, you come back the same way – step into the tesseract that is back when and where you are, and it does its magic and the one variable that changes – time – flips, and instead of being back there ten thousand years ago, here you are, back in the present.

But as it turned out, time travel had some odd, or at least not-obvious limitations.  Kramer said that this was party due to the fact that time travel was so new, and partly, I think, because they didn’t fully understand the math or physics that underlay it.  They could make it work – they had made it work –but apparently no one completely understood how it worked.  But he explained to me what they had learned.

Kramer:  “First, we have established that one cannot use the past to change the present – one cannot go back in time and kill Hitler, for example, tempting though that might be.”

Yeah?  Have they tried?  I’d sure as hell try.

So I asked.  “Did you guys try?”

Kramer glared at me.   “Damn right we tried.  Nailed him, too.  Only it doesn’t matter.”

“What?  Why not?” I asked. “Why doesn’t our present change, if you go back in time and change something in our past?  I don’t get it.”

“Excellent question,” White said smoothly.  “Why this is – that is not well understood.   The prevailing theory, though, is that the present, our present, is immutable, because of a theory of multiverses.  That is, we don’t travel back into our past per se, but rather back into a past that the time travel process itself calls into being, a past identical in all ways to our own, with the simple problem that whatever is done back there, has no change on the present we return to.”

“In other words,” he said, “you can go back in time, kill all the Hitlers you want, but when you come back to our time, our history includes Hitler; is unchanged.”

But wait a minute.

“Wait,” I said.  “Is the past we go to the real past, or a fake past, called up out of the ether?”

“Excellent question,” he said again.  Guy must have given this lecture, answered all these question hundreds of times before.  He was unflappable.

“It’s both,” he said. “It’s the real past – we see the actual events that happened, observe historical events that we know happened – all the data matches.  But at the same time, it’s parallel, dual, identical to our past, but not our past.  It’s a past on a different track:  equally real, equally viable, solid, real.  It exists.  But there’s a disconnect somewhere.  Like I say, you can kill Hitler back there, but whatever you do, the present you return to – our present – includes the bloody history of Europe in the thirties, and World War II.”

“That’s why the program has evolved as it has.  All time travel can do is let us learn from the past.  We cannot change the past we know in our present.  That we cannot do.  But we can change our future, change our behavior in the future.  If we learn, for example, why mammoths became extinct in North America about twelve thousand years ago, maybe we can prevent some other extinction events in our time.”

Kramer jumped back in.  “And time travel has – so far, at least – strict, but poorly understood limits on retrieval.”

“On retrieval?”

“Yes, bringing material forward, from the past.”

“It’s a phenomenon called “quantum identification.”  Each time traveler, and all of his or her equipment must first be scanned at the quantum level, before transmission into the past. This scan provides the template, as it were for retrieval back to our present. “

“But only what is scanned can be retrieved.  In practical terms, what this means, at least at present, is that only what is sent back in time can be retrieved, brought forward to the present.  So, no mammoths, no cave men, not even tissue samples, as yet, can be brought back.”

Now that’s weird.  Why not?  Why can’t they bring anything back?   Look I know I’m not a physicist, and I’m sure I could never understand the math, but it seemed so unfair.  I mean, wouldn’t it be cool if you could go back in time, and bring back a baby mammoth or something?  Can’t they figure that part of it out?

Matter is energy, I guess, and I know we’re not talking about travel to a place, but travel to a different time.  Maybe a different kind of energy?  I don’t know.  And White and Kramer didn’t – or couldn’t – explain it in a way I could understand.

But I got the rule, though.  That I understood.  Nothing from back then comes back to here and now.  But not clear, and not fair.

He was still talking.

“Now this rule can be bent, even if we can’t yet break it.  So, for example, data stored electronically can be brought back – photos on digitized chips, digitally stored voice or video recordings.  Drawings, notes, those are fine too.”

Well, that’s interesting.  I’ll bring a sketch pad, to go with my cameras.

“But intriguingly, that is it, at least for now.  Nothing more can be brought back.  Even the dirt that one would expect to find on the shoes or clothing of returning time travelers does not return to the present.  We haven’t found even a microbe, or bacteria.”

“So the problem of quantum identification is an intriguing, and perplexing one.”

Well, those, it seemed, were the rules of time travel.  The math supporting all this was, I was given to understand, remarkably complex, incredibly sophisticated.  I am not a mathematician, thankfully, so they didn’t even try to explain that all to me.

On to the time beacons.

The way it worked was that from any of the three centers, travelers would be shifted back in time, but not transported through space.  They’d end up right where they had been – in Arizona, or Missouri, or Alaska, simply back in an earlier time.  All well and good, but then your time traveler wants to actually, you know, travel.  Walk around, see the country, do some research.  So for the duration of that trip, the time traveler is wandering around, travelling, doing whatever.

So each traveler is given little beacons, about the size of a tea light, to send at the same time every day, sort of like checking in, saying all is well.  It just triggers a flash on the tesseract sensors, letting the monitors know where you are (since the terrain then is the same geographically as the terrain now), and that you’re still alive, well enough to send the beacon.  And every traveler was given an emergency beacon, saying, basically, “send help now!”

And, up until now, it had been safe.  So long as a given station kept running, the time traveler could always just come home.  Or if he or she needed help, a second team could be sent back to help out.  Which they told me had never been necessary.

And Carver had gone back, successfully, since he’d sent two of the time beacons.  But three days ago, Carver hadn’t sent the beacon.  And none had come in since.  And then, yesterday, the telemetry and chronometers and everything at ASU had gone offline.  Everything had been debugged, power cables checked, tech guys called in – everything.  But for some reason, stubbornly, obstinately, the station remained down.  Never happened before.  Shouldn’t have happened now.  In fact, it was theoretically impossible.

The only problem was that it had happened.  An “oh shit!” moment for the people at DARPA.  Because they couldn’t tell what had happened to Carver, and because the station was down, they couldn’t just zap someone back to find out.

But DARPA had a protocol for situations like this.  Even though, as I say, it was theoretically impossible, they had planned for it.

And now, I was part of that plan.