Some Additional Thoughts on the Atlatl


In my recent entry on the atlatl and dart, I speculated about the reason why its use faded away, and was largely supplanted by the bow and arrow. I wrote:

In fact, darts thrown by atlatls are so effective that it is interesting to speculate about why that technique was largely supplanted by the use of the bow and arrow. I suspect that it may have something to do with the declining size of prey animals. As mammoths and mastodons and the other giant megafauna became extinct, hunters had to turn to smaller, lighter prey, and it may be that the heavy firepower of an atlatl was no longer necessary.[1]

And I think that there may be some merit to that idea. Recently, however, I received correspondence from Dr. Karl Hutchings, whose work on lithic fractures in stone points has provided strong evidence that atlatls were used by the first people to enter the Americas, even though no direct evidence of atlatl use from that time has yet been found.[2]

In his letter to me, Dr. Hutchings has postulated some alternate (or additional) theories about why the bow and arrow so largely supplanted the atlatl. With his permission, I quote at length:

I also read with interest your thoughts concerning the persistence of the atlatl vs. the acceptance of bow technology.  My own thoughts on the matter are a bit different.  It may be noteworthy that recent users of the atlatl hunted small game with it.  For example, Australian Aborigines hunted small game (e.g., reptiles) with the atlatl (they call it a Woomera of course), and ducks were being hunted with the atlatl up until the 1960s in Mexico.  So I don’t think game size per se is necessarily the key factor, though it may figure into it.  Instead, I expect that the nature of the terrain (i.e., open vs. forested; rocky vs. “cushioned” [for want of a better word]) and the relative level of human aggression were important factors. 

The atlatl makes sense in open terrain where the arm motion is unrestricted, and where a long-distance, arcing trajectory is unimpeded. Under such conditions it would be especially beneficial for hunting herd animals.  But it would be effective in some other conditions as well.

The atlatl is quite effective at close range for hunting small game, but can be hampered by the nature of the “ground cover”.  In rocky terrain, one can expect a lot of broken darts regardless whether one hits the small game target, or misses entirely – in either case, the dart is going to hit the ground, since even if the target is hit, the dart will likely continue through it.  I suspect that the atlatl is not preferred in such rocky environments, but on soft (e.g., humic, marshy, sandy, or even water) terrain (like the Australian and Mexican examples), this would not be a problem.  In contrast, archers may not have experienced as significant a problem in rocky terrain due to the flatter trajectory (i.e., increased inherent accuracy), and reduced “cost” of arrows (relative to much larger darts).

The other likely factor is the relative level of human aggression.  The bow is, to a great extent, a weapon of warfare due to the low cost of projectiles, the ability to carry very large quantities of projectiles, and the ability to shoot from positions of cover.  So, in those areas where the bow was adopted due to interpersonal aggression, it may make sense to abandon the atlatl, and simply use the bow as a dual purpose weapon. 

Of course, the reasons for preferring one vs. the other are likely even more complex than this, and undoubtedly incorporate concerns of economy, ethnicity, aesthetics, and more.

Just my speculations on the issue.[3]

Dr. Hutchings’s comments highlight several aspects of my fascination with the Pleistocene period in North America.

First, Dr. Hutching’s ideas all make sense to me, and I had not considered any of them.

Second, I still think that there is merit to notion that these exceptionally skilled hunters may have adapted a lighter technology to lighter game, as the megafauna disappeared. Why continue to use heavy artillery, as it were, for lighter prey? Of course, the atlatl/dart technology could have been (and was) adapted for use on smaller animals, Dr. Hutchings noted above. Still, I think that at some point, as the darts shrank, it became just as effective and easy to use bows and arrows. This ties in with a point that Hutchings makes above – there is a lower cost to make and replace arrows than darts.

Another question is why, after bow and arrow technology was adopted, the atlatl/dart system was apparently no longer used even in against large animals in the open, grassy country that, as Hutchings notes, is optimal for it. I am thinking here about hunting bison or elk on grassland. I understand that the Paleo-Indians at this time had to hunt on foot, and it may be that they could stalk prey more effectively and make better use of cover with a bow, rather than an atlatl, which requires the highly visible standing, throwing motion. Nonetheless, large animals on open terrain remained, but for some reason, the technology shifted from atlatls to bow. Why?

Of course, one additional piece of information that might shed some light on this issue is the pattern of settlement/exploration of the continent by the first people here. What did they preferentially hunt? And where, i.e. in what type of terrain? Perhaps as the megafauna disappeared, the Paleo-Indians had to shift to hunting different game, in different terrain, and the change in terrain drove this shift in technology.

Ultimately, I suspect that there is no single explanation of this technological shift. Scarcity of good stone may have influenced knappers to make more, but smaller points – who knows?

My point here is, the fact that we know so little about life in the Americas thirteen or so thousand years ago is the very reason that it is so fascinating to me, and why I applaud creative scholars like Dr. Hutching who are doing such interesting work.



[1] “Atlatl and Dart,” February 19, 2015.

[2] Indeed, his work formed much of the basis for the “Atlatl and Dart” entry.

[3] Correspondence of February 25, 2015, from W. Karl Hutchings, Ph.D., Assistant Professor, Anthropology (Archaeology), Thompson Rivers University, Kamloops, BC V2C 5N3.

Atlatl and Dart

So you’re hungry, and you want meat, and it’s thirteen thousand years ago in North America. There are no firearms, no guns, no steel knives. How are you going to hunt something to eat? And you want something big enough for everyone in your band to eat – a rabbit won’t do. You want something big, and, therefore strong, and fierce and fearless.

Well, you think you’ve got four options: Spear; javelin; bow and arrow; atlatl and dart. But, you’re wrong, so sorry: The bow and arrow haven’t been invented yet; haven’t come into use in North America yet. So that leaves three options:

You could use a spear. A spear is a handheld thrusting device, made of a wooden shaft, tipped with a very sharp knapped point. Very nice, but of course, you’ve got to get right up next to whatever it is you’re trying to kill, and believe me, right about now, what ever it is you’re trying to kill, is trying to kill you right back.

You could hunt with a javelin. A javelin is similar to a spear, but lighter, and thrown by hand. But these big animals – the mammoths, the mastodons, all have really thick hide, and fur over that. You can wound them, maybe, irritate them, but they’ll just run off, or worse, charge you. You just don’t have the strength, the speed, the leverage to throw a javelin hard enough to really be effective.

Or you could use a dart, flung from an atlatl.

A dart? An atlatl? Huh?

Read on, dear reader, and learn more about the atlatl, and how it changed the world.

The term ‘atlatl’ has come, in recent years to be used in lieu of the former term ‘spear-thrower.” “Atlatl” itself is word from the Nahuatl language (Aztec). But whatever term is used to describe it, the atlatl is an ingenious and effective invention. It’s based on the principle of leverage. In much the same way that a lacrosse player, using his or her stick, can throw a lacrosse ball much faster and farther than by merely using his arm, an atlatl let a hunter hurl a dart much faster, farther and with much more force than by throwing a javelin.

Are you familiar with those plastic molded tennis ball throwers that you use to throw a ball for a dog? That is very similar to an atlatl, in the sense that it lengthens the arc through which the tennis ball travels before it is released. As a result, the ball gains velocity, leaves the thrower at a higher rate of speed than if you just threw it with your puny human arm, and therefore travels much faster and farther.

Same thing with an atlatl.

An atlatl is a wooden shaft, with a hook or notch at one end. The operator (you) holds the other end. The butt of a dart is hooked into the hooked end of the atlatl, and then the operator also holds the shaft of the dart, where it lines up with the handle end of the atlatl. Then the operator, you, cocks his (or her) arm back, and while retaining a firm grasp on the handle of the atlatl, releases the grip on the dart. As the arm moves forward, the momentum of the throw is transferred from the thrower’s arm to the atlatl, down the shaft of the atlatl to the butt end of the dart, and thus, the dart is propelled in a larger arc, than the arm alone could give.



Darts were designed for use with atlatl. They are thinner, and lighter than handheld spears, and they can be long – five to seven feet in length, maybe more. They look like gigantic skinny arrows: A point at one end, and feather fletching at the other. The shaft bends and flexes in flight, and the fletching helps the dart fly true.

And it really works. The atlatl can propel the dart at speeds up to 100 mph.

It’s not intuitive – it takes skill and practice. But when used by a capable operator, it gave hunters a tremendous advantage: The atlatl lets a dart be thrown much faster, much harder, and much farther than a javelin. And, for that matter, a dart thrown from an atlatl is a more effective hunting tool than an arrow in each of three measures: “how hard it hits (kinetic energy), how hard it is to stop (momentum), and how effectively it penetrates (sectional density).”[2] According to one study, Hrdlicka, D. “How Hard Does It Hit? A Revised Study of Atlatl and Dart Ballistics,” The Atlatl, Vol. 16, No. 2, 2002, a dart beats an arrow in each of these three categories. His calculations are beyond the scope of this note, but his conclusions are worth noting:

When an object is in motion, it has kinetic energy. When it strikes something, that energy is transferred. This is the basic force of impact – how hard the weapon strikes the target. . . . Kinetic energy is very dependent on velocity. A bullet, because it is moving so fast, has incredible amounts. A .30-06 has roughly 60 times the kinetic energy of a primitive arrow. And yet Native Americans used those primitive arrows to hunt not only deer, but bison as well. . . [B]oth the light dart and the heavy dart seem weak compared to firearms, but they have more kinetic energy than arrows. . . . . . [T]hey would be sufficient to bring down even the toughest game — assuming it is in the effective range. For an atlatl, the effective range is perhaps 50 yards . . .

While kinetic energy determines how hard an object strikes, it doesn’t determine how far it penetrates. That’s where momentum comes in. . . . Momentum is the tendency of an object in motion to STAY in motion. Anyone who has pushed a car in neutral and then tried to stop it will understand this — the more momentum it has, the more resistance it will take to stop it.. . . Projectiles with a lower momentum, like the arrows, may have trouble penetrating thick hide and can be stopped fairly easily if they hit bone. Projectiles with a lot of momentum, like the spears, will go through hide, flesh, bone, and organs, penetrating until they encounter enough resistance to stop them. More momentum also means the projectile is less likely to be deflected by branches or underbrush, so it can be used in different types of terrain.

In addition, momentum is a factor in “knockdown”. A heavy atlatl dart has enough momentum to knock a 40 pound animal completely off its feet and will definitely affect a larger animal. Objects with less momentum, like the arrows or the .357 magnum, will have a much smaller effect. . . . Darts are much more effective in terms of momentum, even better than the .357 magnum. Mass and velocity are equally important in momentum, and darts have quite a bit of mass. It would take more resistance to stop them, which means they would be more effective at penetrating deeply enough into the target to hit a vital area.

Momentum alone isn’t enough for calculating penetration . . . A Ping-Pong ball thrown at a pop can will bounce off. A BB will go right through. What makes the difference? The sectional density. Even though they may weigh the same, in a BB the weight is much more concentrated. Since it is striking a smaller area on the target, more of the momentum is conserved, and it will penetrate deeper. Other factors being the same, a denser projectile will always penetrate more effectively than a lighter one. . . . Atlatl darts are very effective in terms of sectional density. The weight of the long shaft is concentrated in the small diameter, making them more efficient than either arrows or firearms (even the mighty .30-06). This means that the momentum is conserved better, which means the darts will penetrate better.[3]

Another study noted that a dart thrown properly from an atlatl carries more than four times the kinetic energy of a “modern arrow fired from an efficient modern compound bow” (emphasis added).[4] It is worth noting that the use of the atlatl persisted in many places, even after the invention of the bow and arrow. For example, “in his account of the Desoto expedition to the Southeastern United States in the 16th century Garcilaso de la Vega noted that the spearthrower propelled darts ‘with extreme force, so that it has been known to pass through a man armed with a coat of mail.’”[5]

This power and efficiency helps explain why the atlatl was so successful and so widely used.

The range and power advantage provided by the spearthrower . . . , relative to the thrusting-spear or javelin, could have provided Paleoindian hunters with the ability to successfully penetrate the armor-like hides of mammoths . . . greatly increasing a hunter’s chance for success. Likewise, the device’s portability likely permitted Clovis hunters to avoid alternative big game hunting technologies, such as traps or drives coupled with killing lances, thus maintaining a highly mobile subsistence strategy.[6]

An atlatl and dart offered much more power at a greater distance than could be obtained from a javelin. And, of course, hunting from a distance is a benefit for hunters going after large and potentially dangerous game – mastodons, mammoths – since thrusting a spear at an enraged elephant is very dangerous. Don’t try it at home. Don’t try it anywhere.

It may seem counterintuitive that these long darts, flexing through the air toward the prey would be effective hunting tools, but as one author put it,

For tens of thousands of years, it was the primary hunting weapon on earth. Dart points have been found in mammoth bones, and they have been tested on modern elephant carcasses with impressive results. While it may not be as effective as a rifle, it is certainly effective enough. Just how dead do you need your supper?[7]

In fact, darts thrown by atlatls are so effective that it is interesting to speculate about why that technique was largely supplanted by the use of the bow and arrow. I suspect that it may have something to do with the declining size of prey animals. As mammoths and mastodons and the other giant megafauna became extinct, hunters had to turn to smaller, lighter prey, and it may be that the heavy firepower of an atlatl was no longer necessary.

Atlatls have been widely used around the world, in Europe, the circumpolar regions, southeastern Asia, and North America. Atlatls were in use in Europe over 17,000 years ago, and it was long supposed that atlatls came into North America via the Bering land bridge, described earlier. This would mean that the first people known to have inhabited the Americas, the Clovis people, would have been using atlatls.

But no one could say for sure that that was the case. Although atlatl use has been confirmed in North America going back nine or ten thousand years,[8] there has been no definitive evidence that atlatls were used by the Paleo-Indian culture known at the Clovis People. No one has found an atlatl that old. The atlatls that have been found dated from much more recently, even into the 1400’s, and later.[9] “There is no reason to assume that early migrants to the New World could not have possessed the device, but there is currently no empirical evidence that it was actually used by Paleoindian hunters.”[10]

Recently though, in an ingenious bit of science and research, Dr. Karl Hutchings of Thompson Rivers University in Kamloops, British Columbia, Canada has done a study which permits the strong inference that atlatls were used in North America during the time of the Clovis people, earlier than any fossil evidence demonstrates.


Dr. Hutchings studied patterns of lithic fractures on stone points. That is, he studied the micro features of fracture patterns on stone points. His (and others’) prior research had demonstrated that certain fracture patterns are produced by the force which causes the fractures, i.e. how fast and hard the stone point hit a target.

Dr. Hutchings studied 668 stone points and fragments associated with Paleo-Indian cultures. These were mostly fluted[11] points made of chert, flint, quartz, obsidian, jasper, and chalcedony. “The points were recovered from sites and localities on the edge of the Southern Great Plains, the Southwest, and Far West of North America.[12]

So Hutchings is looking at these points, and sees fracture patterns consistent with a high velocity impact. High enough that the point (attached to a javelin) could not have been thrown by hand. As the study noted,

Fracture velocity data derived from the damaged surfaces of North American Paleoindian points  demonstrate that at least some Paleoindian points were subject to much higher loading rates than can be achieved without mechanical assistance. Since North American archaeologists would generally agree that there is no supporting evidence for the use of the bow and arrow during the Paleoindian Period, the spearthrower is, therefore, indicated.[13]

This is a significant, and very smart finding. As the paper notes, there is no evidence that bow and arrow technology was available to the Clovis people at that time – some thirteen thousand years ago. And there is no known alternate mechanism which could have propelled these points at high enough velocity to have produced the pattern of fractures Dr. Hutchings found. Couple this with the fact that the atlatl was known to have been used in Europe and Asia thousands of years before the time period in question, and the conclusion seems eminently reasonable: The first Americans, the Clovis people were hunting animals – big animals – with atlatls.





[1] Illustration courtesy of National Park Service and US army, but found at National Geographic News,

[2] Hrdlicka, D. “How Hard Does It Hit? A Revised Study of Atlatl and Dart Ballistics,” The Atlatl, Vol. 16, No. 2, 2002,

[3] Hrdlicka, D. “How Hard Does It Hit? A Revised Study of Atlatl and Dart Ballistics,” The Atlatl, Vol. 16, No. 2, 2002,

[4] Hutchings, W.K., and Bruchert, L.W., “Spearthrower Performance: Ethnographic and Experimental Research,” Antiquity 71 (1997): 890 – 97, 894.

[5] Hutchings, W.K., and Bruchert, L.W., “Spearthrower Performance: Ethnographic and Experimental Research,” supra, 895.

[6]W. Karl Hutchings, “Finding The Paleoindian Spearthrower: Quantitative Evidence For Mechanically-Assisted Propulsion Of Lithic Armatures During The North American Paleoindian Period.” Journal of Archaeological Science 55 (2015) 34-41; Publ. Elsevier, online, Jan. 3, 2015, p. 35.

[7] Hrdlicka, D. “How Hard Does It Hit? A Revised Study of Atlatl and Dart Ballistics,” The Atlatl, Vol. 16, No. 2, 2002,

[8] “The earliest concrete evidence for the use of the spearthrower in the New World is currently represented by the spearthrower hooks from Warm Mineral Springs, and Marmes Rockshelter. The 9000 to 10,000 year old associated dates suggest that the spearthrower was in use by at least the Early Archaic Sub-Period.” Hutchings, supra, p. 35.

[9] See, for example the map showing the distribution of atlatls found in North America.

[10]“Perhaps more than any other New World culture, the Clovis Paleoindian complex has been popularly defined by a single artifact form; the fluted Clovis point. While there is no doubt that fluted points were used to dispatch late-Pleistocene megafauna . . . the question remains: how were these points used to bring down such large game? [I]t is not known explicitly whether this weapon took the form of a thrust spear, thrown javelin, or mechanically propelled spearthrower dart, since no hafted fluted points have been recovered to date.” Hutchings, “Finding The Paleoindian Spearthrower: Quantitative Evidence For Mechanically-Assisted Propulsion Of Lithic Armatures During The North American Paleoindian Period,” supra, p. 34.

[11] The fluting is diagnostic of Clovis culture, and its successor, Folsom.

[12]Represented sites and localities include Murray Springs, Naco, Dent, Lehner, Lindenmeier, Folsom, Rio Rancho, Blackwater Draw, Sunshine Well, Tonopah Lake, and the Dietz site (interior citations omitted), as well as many lesser known, and unreported sites and localities.” Hutchings, p. 37.

[13]W. Karl Hutchings, “Finding The Paleoindian Spearthrower: Quantitative Evidence For Mechanically-Assisted Propulsion Of Lithic Armatures During The North American Paleoindian Period.” Journal of Archaeological Science 55 (2015) 34-41; Publ. Elsevier, online, Jan. 3, 2015, p. 35.

Why So Fast, Pronghorn?

Quick! What’s the second fastest land animal in the world?
Everyone knows that the Cheetah is the fastest. But who’s number 2?
Give up?

It’s America’s own: The Pronghorn.


And what a strange – and unique – animal it is.

It looks like an antelope. But it isn’t.

Its scientific name is Antilocapra Americana, which means, American antelope-goat. But while the pronghorn shares many of the features of deer, antelopes and other ruminants: a four-chambered stomach, cloven hooves, and a body shape similar to that of antelopes; it is not an antelope, nor a deer; not a goat, not a sheep. It is unique. It is the sole remaining member of the family antilocapridae. Its closest taxonomic relatives are the giraffids (giraffes and okapi).

Once, back in the Pleistocene, there were twelve different species of antilocapra in North America.[1] The other species differed in size and horn type from the Pronghorn: Ramoceros had long forked horns, and was much smaller than the pronghorn; Hayoceros had pronged horns above its eyes, like the Pronghorn, but also had another pair of straight horns behind those; Stockoceros had four horns.

But they are all extinct – only the Pronghorn survives.


They do look like antelopes. Pronghorns range in size from 75 to 130 pounds, and stand about three and half feet high as the shoulders. They are predominantly a rusty-reddish color, with white patches on their bellies and rump, and white stripes on the throat. They flash the white patch on the their rumps to signals others of danger. They mate in the fall, when males fight rivals to corral a harem. And they fight using their odd pronged horns – again something unique to the Pronghorn.

You may know that antlers grow each season, and then are shed, only to grow again the following year; while horns on cattle or bison are permanent. The Pronghorn falls somewhere in between. It is the only animal in the world with branched or forked horns; and the only animal in the world to shed its horns. The horn begins with a bony growth, and then grows up over that; and then is shed annually. The horns of the male pronghorn are much larger than those of the female, and can grow to fifteen inches in length. The horns of the females are smaller, and rarely have prongs.

In addition to the unusual pronged horns that give the animal its name, the pronghorn has another unusual anatomic feature. It has extraordinary vision. Its eyes are the largest, relative to its size, of any North American ungulate; and it has a nearly 300 degree arc of vision, without moving its head or eyes. Pronghorns see movement more clearly than stationary objects, and can detect movement up to four miles away.


And that remarkable speed: The Pronghorn is the greatest runner in the world. Its speed is second only to the cheetah. A pronghorn can run at speeds up to sixty miles per hour; a cheetah, can run – for short distances – at speeds up to seventy miles an hour. But the cheetah flames out after a few hundred yards. The Pronghorn does not. True, they can’t sustain speeds of sixty miles an hour, but one source says that they can sustain speeds of 57 miles per hour for nine miles.[2]  And they can run at speeds in excess of forty miles per hour for over thirty minutes. As one author put it, “if pronghorn ran marathons, they would complete the course in 40 minutes.”[3]

The pronghorn is designed for speed, and endurance. Its bones are lightweight, relative to its size; the trachea and lungs are enlarged; and it runs with its mouth open, to take in more air. And the pronghorn’s capacity to utilize oxygen is incredible. In one test, scientists found that pronghorns use five times more oxygen per minute while running than other mammals of comparable size. But remarkably, the scientists who have studied the pronghorns and their adaptation for speed have found nothing else, really.

“[T]he researchers discovered that the pronghorn is just a little bit better at everything. Compared with the goat, it has bigger lungs with which to absorb oxygen, slightly more blood hemoglobin with which to transport the oxygen from the lungs to the muscles, and slightly bigger and leaner muscles containing a higher concentration of mitochondria–the cellular organelles that burn oxygen to provide power for muscle contraction. In other words, there are no tricks to the pronghorn antelope. It has simply perfected the same equipment that all mammals have.”[4]

So why this speed? Why has the pronghorn evolved this unequaled capacity to run at very high speeds for very long times? Why that incredible vision?

In a word: predation. Evolution is driven by adaptation. Something drove the pronghorn to develop this unmatched capacity to run and run and run, at high speed, over enormous distances. The question then is this: What nightmare creature had the speed and endurance to drive pronghorns to evolve their exceptional combination of speed and endurance?

The answer is: No one is really sure.

It wasn’t wolves, and it wasn’t coyotes. Newborn or injured pronghorns are vulnerable to predation by wolves and coyotes. But adult pronghorns are much, much faster than coyotes: They can outrun them easily. Wolves are pursuit predators. They hunt in packs and employ relay strategies where some of the wolves chase a prey animal, and then others of the pack take up the pursuit, eventually tiring and wearing down the prey so that it can be taken. And this perhaps was an effective strategy against the pronghorn when wolves roamed the same country as the pronghorns do. But for the most part wolves do not prey on pronghorns. They have other prey – elk, for example, and – today, at least – are not commonly found in the type of country where pronghorns roam.

Ambush predators like mountain lions don’t have enough cover to successfully stalk and kill pronghorns regularly.

So if it wasn’t coyotes, nor wolves, nor mountain lions, what animal was it? What nightmare creature had the speed and endurance to drive pronghorns to evolve their exceptional combination of speed and endurance?

There are two primary contenders: The American cheetah, and the hunting hyena.

One theory is that the pronghorn developed its remarkable running ability in response to predation by the American Cheetah. The name is not entirely accurate. Although they were fast – very fast – the two species of American Cheetahs were not cheetahs at all, but more closely related to mountain lions (cougars). Nonetheless they showed evolutionary adaptations designed for speed. One of them – Miracinonyx trumani – lived on the prairies and plains. It may well have been the pronghorn’s partner in the evolutionary race for speed and endurance.

But recently, Miracinonyx fossils have been found in the “wrong” habitat – in steep, rocky hillside areas – leading to some speculation that the American Cheetah lived more like a modern day snow leopard, than its African namesake.[5]

And cats tend to be sprinters rather than marathoners. Since the pronghorn can sustain its incredible speeds for such a long time, it seems likely that the running ability evolved in response to pressure from some predator that could run at high speed for long distances. And, in fact, there is another possible explanation for the pronghorn’s speed and endurance: The American hyena, Chasmaporthetes ossifragus, called the hunting hyena.

Not much is known about the hunting hyena. It is the only species of hyena to cross the land bridge from Eurasia to North America. “Fossil remains of Chasmaporthetes have been found at 4 sites in Florida, 3 sites in Arizona, 2 sites in north Texas, 2 sites in Mexico, and 1 site in New Mexico. . .[6]  Chasmaporthetes is called the hunting hyena because it, too, like the America cheetah, shows adaptations for speed. Its legs were long and slender, and it probably hunted in packs on open grassland. Today, African hyenas are tenacious pack predators, often chasing prey for long distances. Thus is seems possible that the American hunting hyena might have been the pronghorn’s partner in the evolution of this speed and endurance.

The American cheetah is long gone now, and the hunting hyena went extinct roughly seven hundred eighty thousand years ago. Still, the pronghorn survives; and still it carries the adaptations it evolved: the vision to see danger from far away, and the speed to run and run and run, as long and as fast as possible, to escape from whatever it was that pursued it – the American cheetah, or the hunting hyena. Whatever it was, it haunts the pronghorn’s dreams still.

Links to sources and articles of interest:

Yoon, C. “Pronghorn’s Speed May Be Legacy of Past Predators,” NY Times, Dec. 24, 1996.

Barnett, R., et al. “Evolution of the extinct Sabretooths and the American cheetah-like cat. 2005. Elsevier Pub.

Switek, B. Did False Cheetahs Give Pronghorn a need for Speed? Phenomena, January 8, 2013.

Switek, B. “The Hyena Who Saw the Canyon,” Laelaps, Wired.Com
March 3, 2011.


Top photo by Stacy Dunn,

Middle Photo by Yashin S. Krishnappa,,_2012).jpg

Bottom photo by David Tremblay,


[1]Wikipedia reports that there were still five species when humans first entered the Americas, although the statement does not have a citation or reference.

[2] San Diego Zoo, Pronghorn, Antilocapra Americana, May, 2009.

[3] Nowak, Rachel. “The Pronghorn’s Prowess,” Discover, December 1, 1992.

[4] Nowak, Rachel. “The Pronghorn’s Prowess,” Discover, December 1, 1992.

[5] See, for example,


This Just In –

It has taken 46 years to get the answer.  Well, twelve thousand six hundred and forty six, to be more precise.  And it’s all due to a little boy.

He lived in Montana.  Maybe he was a happy, chubby little fellow, toddling about, smiling, learning to talk.  We know he was very much loved, because when he died, at about two years old, he was buried with hundred of spear points, and other stone tools, stone points, and his body was painted with red ochre. One thing that is evidence of how much he was loved is that buried with him were carved elk antlers that were hundreds of years older than he was – heirlooms, presumably.

He died roughly twelve thousand six hundred and forty six years ago, and was buried, and his people moved on, and spread across the land.

And then, forty six years ago, in 1968, his body was found, on a ranch in Montana near the town of Wilsall, northeast of Bozeman.  The site is called the Anzick site.  It was discovered by accident, and contained many spear points and stone tools, all of them Clovis-type tools, as well as partial skeletal remains of this small boy.

But there is something very special about this boy.  For he has shared a secret with us.  He has told us much about his ancestry, and the ancestry of the Native Americans who live here today.

To understand this, let’s step back a little.  At present there are two main hypotheses about how people first came to the continent.  One, the subject of prior blog entries, is that people came from Siberia across Beringia, the vast land bridge that connected Siberia and Alaska.  The second, the Solutrean hypothesis, posits that Clovis predecessors came, across the Atlantic from southern Europe, following the edges of the ice during the last Glacial maximum.  This would mean that they used hide-covered kayaks, or other similar watercraft. This hypothesis derives, in part, from the similarity of Clovis points to stone tools found in Southern Europe.

So:  We have two very different hypotheses; two doors to the Continent in essence:  One by boat to the East Coast; the other on foot down through Alaska, and south.

Here’s where the little boy comes in.  Genetic analysis, performed by a team led by Eske Willerslev, a paleobiologist at the University of Copenhagen, has shown that the Native Americans in North and South America have genes consistent with those of people from Siberia.  The little boy’s genes show that “the gene flow from the Siberian Upper Palaeolithic Mal’ta population into Native American ancestors is also shared by the Anzick-1 individual[1] and thus happened before 12,600 years BP.”[2] What this means is that those genes are from Siberia.  But this little boy, living and dying here in North America, over twelve thousand years ago, had them too.  And those genes are shared with modern Native Americans.  This boy’s ancestors came from Asia. This is strong evidence in support of the hypothesis that the Americas were peopled via Beringia.

Does this mean the end of the Solutrean hypothesis?  Well, it is strong evidence, but not necessarily the death knell for the Solutrean hypothesis.  After all there is nothing that requires Beringia to be the exclusive means of entering North America.  It is possible that people came in across the Atlantic, too.  And defenders of the Solutrean hypothesis aren’t giving up.  “They haven’t produced evidence to refute the Solutrean hypothesis,” said geneticist Stephen Oppenheimer of Oxford University, a leading expert on using DNA to track ancient migrations. “In fact, there is genetic evidence that only the Solutrean hypothesis explains.”[3]  There is a dearth of DNA data from existing Native American populations, so there may be (as yet undiscovered) genetic evidence supporting an inflow of people from Western Europe.

One interesting thing about this genetic study is that the little boy’s genes are more closely associated with Central and South American peoples than native Americans from the far north.

“The team was able to determine that the Anzick genome was much more closely related to Native Americans than to any other group worldwide. The child’s DNA more closely resembles that of Central and South Americans than Native Americans from the far north, although the relationship is still very close. . . Comparing the Anzick genome with that of a 24,000-year-old Siberian boy and a 4000-year-old Paleo-Eskimo from Greenland confirms that Native Americans originally come from Northeast Asia.

How to explain the north-south difference? The team concludes that the most likely scenario is that an ancestral population that lived several thousand years before the Clovis period split into two groups, one staying north and one going south. Just where and when this split happened cannot be determined from the genetic data. . . The northerners then likely mated with peoples who came in later from Asia, and so became slightly more genetically distant from Anzick.”[4]

Like so much having to do with paleontology and archeology, it is only a piece of the puzzle.  But it is an important piece. Thanks to this little boy, and the family who loved him, we now know more – much more – about the peopling of the Americas.

And, appropriately, members of the Anzick family, with the cooperation of various tribes in the area, are going to re-bury the boy’s remains, and so return him to his land.


[1] Anzick-1 is the little boy.  I find it hard to think of him that way.

[2] “The Genome Of A Late Pleistocene Human From A Clovis Burial Site In Western Montana;”

[3] “Ancient Native Boy’s Genome Reignites Debate Over First Americans;”

Clovis – and Earlier

Of the archeological sites which are considered to have signs of pre-Clovis human activity there are four that I want to focus on today, for a reason, which I’ll get to in a minute.

When and how people first came to the New World has long been an archeological mystery.   Whenever the first Europeans arrived here (either in 1492, and thereafter, or earlier, if you prefer, with Leif Ericsson), they found people already living here.  But where had they come from?  And how?  And when?

Beginning in the 1920’s and thereafter, archeologists (and others) began finding large uniquely shaped stone spear points, and thought, “Aha! Here is evidence of the first people to inhabit the Americas.”  The points were unique in that they had a distinctive fluting, which permitted the point to be hafted onto a shaft.  (See the illustrations.)  The first of these archaic points was found near the town of Clovis, New Mexico, and the culture that had created these beautiful tools became known as the Clovis culture. crain-clovis-hh1Clovis Point

The scientists knew these points were old, because, for example, they found some wedged in mammoth bones.  And as dating techniques became more refined, the points were dated to roughly thirteen thousand years ago. [1] At the time of the discovery of the Clovis points, and for a long time after that, that there was no evidence of any human occupation before that time, roughly 13,000 years BP (Before Present).  

So, based on the discovery of these old stone tools, and the absence of evidence of an earlier human presence, the predominant theory developed.  The theory is often called the Clovis First theory.  That theory was fairly straightforward:  During the last glacial maximum, between sixteen thousand and twelve thousand years ago, the sea level was so low that Siberia and Alaska were connected by a vast land bridge called Beringia; and the people who made those Clovis points, the first humans to come into the Americas, had walked across that land; had come here from Siberia, down through Canada, and into the Americas.  And the theory was plausible, because at that time, not only were the seas low enough to permit travel from Siberia to Alaska on foot, across the vast land today known as Beringia, but also, because at that time there was an ice-free corridor which would have let the wanderers pass down from Alaska between the glaciers, and so into Canada, and the rest of the Americas. And, at that time there was no evidence to suggest that people had been here earlier.

Thus, the Clovis First theory says that those people, who came across Beringia between sixteen thousand and twelve thousand years ago, were the first people to enter North America.  And it was thought, that by 13,000 years ago, they and their culture had diffused as far south as Clovis, New Mexico.

It was a very neat theory.  And, for that matter, it’s a theory that may well reflect (a part of) what really happened.  That is to say, it is likely that some people did, in fact, come into the Americas via Beringia, during that time.

But – it may be that that was not the only way that people got here; and it also may be that people got here earlier than previously thought.

Cue four sites of human settlement in the Americas:

Meadowcroft, Pennsylvania

Saltville, Virginia

Cactus Hill, Virginia

Topper, South Carolina

Why?  Why these four sites?

Two reasons:

First, each has evidence of human activity earlier than 13,000 years ago; evidence of the human presence before the Clovis First theory  permits.

One of the interesting things about archeology is that it isn’t like going to a museum.  The discoveries are not complete little villages, all laid out in a neat diorama.  There are no complete sets of bows and arrows, just lying around.  The materials discovered are often fragmentary, contradictory, and require detailed analysis, and some level of conjecture, before inferences may be drawn, and tentative conclusions reached.

To a greater or lesser extent each of these sites is controversial, insofar as each purports to show evidence of human activity before 13,000 years BP, in large part because the evidence is so equivocal.  I’ll review the sites in greater detail later, but for now, it’s sufficient to state that each shows (or claims to show) evidence of human activity much earlier than the commonly accepted dates of Clovis culture.

How much earlier?    A million years?

Five hundred thousand years?

One hundred thousand years?

Nope.  Three thousand years, four maybe, maybe five thousand years, maybe a little more.

I’ve oversimplified a little.  As noted above, these sites are dated using radiocarbon analysis and that method generates different dates than calendar dates.  There are formulas, however, which allow radiocarbon dates to be translated, roughly, into calendar dates, and using that conversion factor, we can derive evidence of human activity at these sites that goes back as far as 20,000 years BP.

Now that is not hundreds of thousands of years, not even tens of thousands of years, but it is thousands of years.  Thousands (plural) of years.   That’s a long time.  Christianity is only two thousand years old; the pyramids were built five thousand years ago.  And we’re back way before that, and, for that matter, way before the Clovis dates.  Thousands of years earlier.

As I say, each site is somewhat controversial.  But let us assume, for now, that they accurately show evidence of human activity thousands of years before Clovis culture developed.

That leads to the second reason to consider these four sites:

Look where they are.  They’re all on the east coast.

They are thousands of miles away from Clovis, New Mexico; thousands of miles away from the ice-free corridor which led down through Alaska and Canada into North America.  These sites are way over in the east.

Somebody did some traveling.

Somebody traveled far enough to be way over in Virginia, thousands of years before the Clovis culture began.  Who?  Where’d they come from? How’d they get here?

These sites therefore, are significant for a number of reasons:

First, they show evidence that there were people here thousands of years earlier than the Clovis First theory posits.

Second, they show that those people, (whoever they were, however they got here, whenever they got here), were widely spread out across North America.

Third, the locations suggest that people must have entered North America much earlier than the dates posited under the Clovis First theory, in order to give them enough time have travelled so far.

But look at this cool map here.[2]

Bering Strait1

See how it shows routes of travel?  The first Americans could go anywhere they wanted (subject to the location of the ice sheets during the various ice ages).  Don’t makethe mistake of thinking that just because Clovis points were first found in New Mexico that that was where the Clovis culture began.  It’s not as though the first people came over the land bridge, directly down to Clovis, New Mexico, devised this new stone technique and then spread out from there.  In fact, Clovis points have been found all over America, and there is no single answer to where it began.  

Still, it is interesting that once was once considered the first record of the peopling of the Americas is now being superseded by evidence of human inhabitation of the Americas much earlier than originally thought, from sites that are very widely diffused.

I’ll bet you’d like the answer, huh?  Who were these people? When did they get here?  How?

Stick around.





[1]Dates are commonly obtained by radiocarbon dating, and the dates are given as RCYBP, which stands for RadioCarbon Years Before Present.  Radiocarbon years do not exactly equal calendar years. Under that measure Clovis culture is thought to have begun about 11,500 RCYBP.  This translates, however (roughly) to 13000 – 135000 years ago. The whole radiocarbon dating/time scale conversion issue is well beyond the scope of this blog, or this blog entry at least.  So for now, let’s just agree that Clovis culture began sometime around about thirteen thousand years ago.


[2] I found this map in the article “Prehistoric Migration of American Indians,” by (I think) Katherine Bolman, BS, MFA, MEd, MSW, EdD., at  The map itself is attributed to Jose Arredondo.  The link to the website is



The Door Opens

It was a simple story, and probably – probably – too good to be true.

Two great vast continents standing open, uninhabited, alone, separated from the rest of the world by two enormous oceans, until the glaciers came, and drew down the sea level hundreds of feet, and so exposed a bridge, a wide corridor of land stretching between and connecting Siberia and Alaska.  And no mere footpath – this now-submerged land, Beringia, was hundreds of miles wide, steppe country, treeless, covered with grasses, and sedges, and dwarf willows.  Huge clouds of mosquitos swirled over the ponds and streams that ran across the land, but they were not sufficient to bother the great herds that walked that land – the reindeer, the caribou, the horses, and bison, and mammoths, and mastodons.


And where the game went, the story goes, the people followed. Up and up, north and east into the shining sun, in the long, long days, following the herds.  North and east, ever on, until those people were no longer in Siberia, but now, in Beringia, and sometime later, in Alaska.  And then Canada, and the land stood open, and they came in, and so peopled North America.  Following the game across the land.

A simple story and a beautiful one.

This is the theory that has dominated thinking about the peopling of the Americas for decades.  These first Americans, so the theory goes, were associated with a specific type of spear point, called a Clovis point, after the town in New Mexico where the ancient points were first discovered.  And they arrived in North America sometime – roughly – no one knows for sure – between 11,500 and 13,500 years ago.

But – Is the story true?  Was that how and when people came to the Americas?  And if true, still other questions remain – was that the only way that they came here? And was that the only time?

Because there are anomalies.  There are doubts.  There are questions.

There are, in short, other theories, and tantalizing hints of evidence to support them.

From the lack of any fossil evidence whatsoever, it is reasonable to conclude that until quite recently both North and South America were entirely uninhabited.  And humans didn’t evolve here.  Yet when Columbus arrived, he found people here; earlier, when the Norsemen came, they found the skraelings – human beings. So somehow, at some point, humans made their way here, into the Americas.  But how?  And when?

There are really only five ways they could have come.  When the glaciers were in full flower, the ocean level was so low that that land bridge, Beringia – hundreds of miles wide – formed between Siberia and Alaska.  Maybe, following the game, bands of people came through that way, and then down through Canada.

Two: Maybe they sailed along the coast between Siberia and Alaska, and then on down the coast.

Three – maybe some people – maybe – sailed along the edges of the glaciers from Europe to Iceland, then Greenland, and island hopped along the Canadian coast and down into north America.

Four – maybe bold sailors sailed right across the Pacific.

Five – maybe equally bold sailors sailed right across the Atlantic.

Maybe they came in different ways at different times. And maybe they came in waves.  The problem is, we just don’t know.

But there is tantalizing evidence that suggests that the Clovis model is overly simplistic, and probably not entirely accurate.  This is not to say that people didn’t come over the land bridge we call Beringia – they probably did.  But when they came, and whether that was the only was they got here, remain unsettled.  The questions remain:

When did people first come to the Americas?  How?

Over the next several entries, these are the questions I’ll be looking at.




The Dire Wolf

When I awoke, the dire wolf

Six hundred pounds of sin

Was grinning at my window

All I said was “come on in,”

“Don’t murder me . . .”

– Robert Hunter & Jerry Garcia

In recent years, the Dire wolf – or the idea of a “Dire” wolf – has become fairly popular.  It’s not just the Grateful Dead song.  It’s part of popular culture in Game of Thrones.  The dread, cunning, rapacious, vicious, enormous Dire Wolf.

The Dire wolf was North America’s own.  Scientists think that it, unlike the gray wolf, evolved on this continent.  And what a wolf it was.

It was big, weighing up to 175 lbs.[1] And strong –  very strong.  Its jaw was larger than that of modern wolves, and it teeth were bigger, and its bite was stronger.  It was well designed for hunting and killing and then eating large prey.

Its scientific name, canis dirus incorporates the word  – dire.  From the Latin meaning “fearful” or “awful.”  Nice.OLYMPUS DIGITAL CAMERA

Like modern wolves it was able to  adapt to all kinds of environments.   Its remains have been found throughout the country, and into South America as well.  It lived in all sorts of habitats – forests, mountains, open grasslands and plains; from sea level to over a mile high. And it was very common. Over 3,600 of them have been pulled from the La Brea tar pits in Los Angeles.

The Dire Wolf was carnivorous.  Scientific analysis shows that its diet favored bison and horses, although it ate mammoths, sloths, and other large prey, if it could catch them.  It was heavily built, and while only slightly larger than modern gray wolves, it weighed probably 25% more.  And, as noted above its skull contained adaptations that suited it for hunting large, heavy prey – its skull was broader than that of modern wolves, and had attachments suggesting that the muscles which drove its jaw were exceptionally powerful.

So far, only bones have been found.  We don’t know what its fur looked like, but everyone sort of assumes that it looked like modern wolves.  So how did it compare to modern wolves?


Well, as noted above, its skull was bigger, heavier and stronger – more suited to hunting and grabbing onto large prey animals. But its braincase was smaller.  I’m not sure that intelligence had to do with anything in this context, though.  Both dire wolves and gray were very successful for tens of thousands of years, so while a gray wolf might score higher on an IQ test than a dire wolf, it doesn’t seem to have made any actual practical difference.

Its legs were shorter and stockier than modern wolves, suggesting that it wasn’t as fast, and not as well suited to the long effortless loping that wolves do.  These anatomical differences, combined with the fact that the dire wolf evolved in North America, while the gray wolf evolved in Eurasia, raise questions about how the dire wolf lived.  Modern wolves are pack hunters – Was the dire wolf?  There is no evidence of sexual dimorphism – the females were the same size as the males, so presumably they engaged in the same behaviors.  But was this the active pursuit of, say, a bison?  Or were they more like hyenas, and scavengers, first, and hunters only secondarily?   Skeletal evidence shows several things that shed some light on its behavior.

First many of these animals survived broken bones.  This implies that perhaps the pack brought food to injured members.  And it suggests that there was some level of pack behavior.

This is supported by scarring on some of the skulls consistent with hierarchical behavior –  dominant wolves grabbing and biting the heads and faces of subordinate animals.

Finally, the dearth of wolf puppy bones found at La Brea also supports the idea that these were packs animals.  They probably left the puppies back at the den while the pack was hunting, and then brought food back to the puppies.

But while it is reasonable to suppose that they were pack animals, the size of a typical pack is unknown.  Were they small, family-based packs like coyotes, (to whom they are closely related)?  Or did they run in larger, bigger packs, better suited to hunting and bringing down large prey?

The gray wolf came over, across the Bering Strait land bridge, from Eurasia, approximately three hundred thousand years ago, and found the dire wolf already here.  And they coexisted for hundreds of  thousands of years.  Presumably, then they filled different ecological niches.  The gray wolf was, it is thought, faster, more fleet of foot, and probably able to run for a longer time than the stouter, stockier dire wolf.  The dire wolf, in turn had a skull better equipped for taking large heavy prey.  So, presumably, the gray wolf hunted smaller faster animals – deer, or elk – while the dire wolf was taking horses and bison.  Or, as some believe, perhaps the dire wolves scavenged.  That would have been quite a sight – a Smilodon, having taken down a camel, or horse, looks up, and sees fifteen or twenty wolves coming in, focused, intent, snarling, ready to take the kill.


As with so many other large animals, the Dire wolf went extinct some ten to twelve thousand years ago.  But the gray wolf did not.  This is a real mystery.  Why the one, and not the other?

There are several theories.  One is that the dire wolf was so adapted to large prey that when the megafauna went extinct, it did too, while the gray wolf was more adapted to smaller prey which survived.  Some have speculated that the dire wolf didn’t so much coexist with the gray wolf as compete with it, and the gray wolf finally won.  Another theory is that the dire wolf became extinct in the face of a new competitor – human beings.

But there are problems with each of these theories – over-specialization; competition with gray wolves, pressure from humans.

First, dire wolves were, according to the fossil remains, very common.  And spread throughout the continent.  As were gray wolves.  If it was pressure from humans, then why would dire wolves become extinct and gray wolves survive?

Dietary analysis shows that dire wolves’ diet differed from that of gray wolves – so they weren’t directly competitors.  Although, once the large slow animals were gone, the gray wolf would probably out-competed the dire wolf for hunting the smaller fast prey – deer and elk – that remained.  But – and it’s a real question – the bison remained.   So why didn’t the dire wolf continue as it had, hunting the buffalo, and thriving?

I think it is reasonable to posit this theory:  The dire wolves were primarily scavengers, although certainly capable of hunting when necessary.  Remember that this was all completely wild country.  In historic times mountain men and other early explorers of the west reported that hundreds and hundreds of buffalo would be killed trying to cross a river (much as still happens in some part of Africa, today, with wildebeest).  So, at times, at least, there would have been ample food for the wolves to scavenge: hundreds of horses, or some mammoths, say, killed trying to cross a river.  And if they roamed in large packs, they were formidable, certainly able to drive a pack of lions from a kill (again, analogous to hyena-lion interactions in Africa, today).

But they were, therefore, specialists.  Not generalists, like the gray wolf.  The gray wolf will hunt and eat deer and elk, but also – mice.  Anything it can get.  And perhaps, notwithstanding what I wrote up above, maybe intelligence does play a role, here; letting the gray wolf see and understand and seize new possibilities, that the dire wolf didn’t.  Then, when whatever happened to wipe out so many of the large prey animals, the dire wolf was ill-suited to adapt.

The answer is elusive and, as yet, unknown.  Each species in an ecosystem is filling a niche so sensitively, and the entire system is so finely tuned, that any little change may throw it out of balance.  In the case of the dire wolf, it may be that there was no single overwhelming explanation for their extinction, but a combination of small factors, which, taken together, pushed it out of its niche, and into extinction.  So, the horse, which has made up a substantial part of its diet, goes extinct.  The pressure on the dire wolves goes up.  Human hunters replace lions and Smilodon, and unlike them, can’t be driven from the kill – and the pressure goes up.  And the humans make more efficient use of the animals they’ve hunted, leaving less for the wolves to scavenge.  And the pressure rises.  Not so much a single extinction event, perhaps, but something more akin to the death of a thousand cuts.

But even though the actual wolf is gone, the DIRE WOLF lives on in song and story.  And for now, that will have to do.

Useful links:

Craniofacial morphology and feeding behavior in Canis dirus, the extinct Pleistocene dire wolf, W. Anyonge, A. Baker,;jsessionid=69EBE865899AA29760D72BCFF14A3E3E.f02t02 (only the abstract is available online).;jsessionid=69EBE865899AA29760D72BCFF14A3E3E.f02t02 (only the abstract is available online).

[1] Not six hundred pounds.  Not even close.  Sorry, Jerry.  Sorry, Deadheads.

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.


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.


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.”


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.


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.


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.


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.

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.


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








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.


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.


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.


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:


[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.