Category Archives: Green activism

That Clovis Overkill Hypothesis? How much evidence is there for it, really?

I am amazed that this Clovis as mammoth murderer to extinction idea still has traction.

I am presenting this here not to convince the reader, but to show that the popular idea of humans as mammoth “extinction machines” has another, valid, side to it.  I was not looking for this article or anything along these lines at the time I found it (a couple of months ago) – but it blew me away, that two BIG names in this area of research (Grayson and Meltzer) had such a paper out there.  In my opinion, this paper eviscerates the Overkill hypothesis.  See what you think:

See “A requiem for North American overkill” Grayson and Meltzer 2003. (Yes, the very same Meltzer who is a co-author on some of the YDB skeptical papers.) All the quotes are from that paper.

The argument that human hunters were responsible for the extinction of a wide variety of large Pleistocene mammals emerged in western Europe during the 1860s, alongside the recognition that people had coexisted with those mammals. Today, the overkill position is rejected for western Europe but lives on in Australia and North America. The survival of this hypothesis is due almost entirely to Paul Martin, the architect of the first detailed version of it. In North America, archaeologists and paleontologists whose work focuses on the late Pleistocene routinely reject Martin’s position for two prime reasons: there is virtually no evidence that supports it, and there is a remarkably broad set of evidence that strongly suggests that it is wrong. In response, Martin asserts that the overkill model predicts a lack of supporting evidence, thus turning the absence of empirical support into support for his beliefs. We suggest that this feature of the overkill position removes the hypothesis from the realm of science and places it squarely in the realm of faith. One may or may not believe in the overkill position, but one should not confuse it with a scientific hypothesis about the nature of the North American past.

They discuss island versus continental extinctions and causes.  And they argue efficiently that projecting island extinctions onto continents – which is VERY commonly done – is a completely wrong extrapolation:

The initial human colonization of island after island was followed by vertebrate extinction. That this premise is true, however, does not mean that it is relevant to continental extinctions. After all, the factors that make islands prone to vertebrate extinction — small population sizes of resident vertebrates, the lack of a ready source of conspecific colonizers, and so on — do not apply to the continental setting.

It is not enough to blame humans for mammoth and mastodon extinctions. Over 30 other species went extinct at virtually the same time – with the lack of evidence of Clovis killing them being non-existent:

How many of those genera can be shown to have been human prey during Clovis times?  The answer is two – mammoth and mastodon—(Table 2) and there are only 14 sites that securely document this relationship [39].  As has long been known [42], this is not a sampling fluke (see Fig. 1). There are more late Pleistocene occurrences of horse than there are of mammoth or mastodon, and nearly as many for camel as for mastodon, yet there are no demonstrable kill sites for horse or camel or for any of the remaining genera [30,31,34,36,37,39]. This is not for want of looking.  Given the high archaeological visibility of the remains of extinct Pleistocene mammals, and their great interest to archaeologists and Quaternary paleontologists alike, if such sites were out there, they would surely be found. Indeed, there is a strong bias in the Clovis archaeological record toward just such sites…

So, the next time you see an “artist’s rendition” like this, think about what you are reading today:

The Extinct Late Pleistocene Mammals of North America

Genus / Common name
Pampatheriuma / Southern Pampathere
Holmesina / Northern Pampathere
Glyptotherium / Simpson’s / Glyptodont
Megalonyx / Jefferson’s Ground Sloth
Eremotherium / Rusconi’s Ground Sloth
Nothrotheriops / Shasta Ground Sloth
Glossotheriumc / Harlan’s Ground Sloth
Brachyprotoma / Short-faced Skunk
Cuonb / Dhole
Tremarctos / Florida Cave Bear
Arctodus / Giant Short-faced Bear
Smilodon / Sabertooth Cat
Homotherium / Scimitar Cat
Miracinonyx / American Cheetah
Castoroides / Giant Beaver
Hydrochoerus / Holmes’s Capybara
Neochoerus / Pinckney’s Capybara
Aztlanolagus / Aztlan Rabbit
Equus / Horse
Tapirus / Tapirs
Mylohyus / Long-nosed Peccary
Platygonus / Flat-headed Peccary
Camelops / Yesterday’s Camel
Hemiauchenia / Large-headed Llama
Palaeolama / Stout-legged Llama
Navahoceros / Mountain Deer
Cervalces / Stag-Moose
Capromeryx / Diminutive Pronghorn
Tetrameryx / Shuler’s Pronghorn
Stockoceros / Stock’s Pronghorn
Saigab / Saiga
Euceratherium / Shrub Ox
Bootherium / Harlan’s Musk Ox
Mammut / American Mastodon (2)
Mammuthus / Mammoth (12)


Only the ones in red have confirmed kill sites (number of sites).  See Clovis hunting and large mammal extinction: a critical review of the evidence (Grayson and Meltzer 2002) .  Also see How Many Elephant Kills are 14? Clovis and Mastodon Kills in Context (Surovell and Waguespack 2008).

The experts in the field don’t sign on to the idea, to their credit (but how about the rest of us and the rest of scientists?) : Continue reading


The Future of Futurism…

Hahahaha –

I was talking with a friend on Skype and marveling at the world having videophones after all this time.  (Anybody remember 2001 A Space Oddysey back in 1967?) That conversation got into talking about how COOL it is to live in these times.  And then it got into how things might change in the future.

If any of this is too off the wall or too nauseating for the tree huggers out there, tough luck!  I am going to talk about it anyway.  🙂

My friend is more than 40 years younger than I am, and he just got married, and is going to see as many changes in his time as I’ve seen in mine.  It is AMAZING how much technology brings into our lives over a span of 70 or 80 years.  It used to be 60.  Hell, it used to be 49!  In 1900 the average life expectancy in the USA was all of 49 years.  Now – as of about 10 years ago – it is 79 years.  So in about 100 years the life expectancy went up 30 years.  30 in 100. WOW! !

So right there we have one way technology has improved life – it has made it longer.  It is laughable when I tell this to people, because t really IS an improvement.  But would you like to know what the most common reaction I get from people?  “Well, extra years don’t mean anything if you are sick.”  They just don’t get it.

What don’t they get?  That 100 years ago at age 19 people only had 30 years more to live.  That NOW we are FORTY NINE when we have 30 years to live – at somewhat the same health level.  REALLY.  So, at the age when people used to die off – on average – we all still have 30 years to live.  So when someone tells you that 50 is the new 30, they are kind of right – but not right ENOUGH.  The average person at 49 now is not looking at spending the next 30 years as a medical invalid.  They are looking at about 20 more years of good living. Continue reading

Past Activist Naughtinesses That Didn’t Make It Very Far – And One That Did

I present four examples of environmental activists and their claims:

Example 1

Back around 1988 there was a claim that 25% of the waste in our garbage dumps was plastic baby diapers.  It was also a time when our store shelves were well-stocked with biodegradable plastic trash bags.

A professor of archaeology at Southern Illinois University thought that the diaper thing would make a good challenge and project for his students.  They all went out to dumps and began counting and measuring and weighing, among the rats and flies.

They found out some notable things in their field work and their later analyses, all of which was in contradiction with what the common wisdom was at the time.  You see, most people then believed that, yes, there was too much plastic being discarded – the old “wasteful American” meme, aimed at one particular class of products.  This even though millions of Americans did, in fact, take up the biodegradable call to arms and tried to buy biodegradable trash bags in their effort to not inure the environment any more than necessary. Continue reading