Martin, Paul S., Twilight of the Mammoths: Ice Age Extinctions and the Rewilding of America. 2005. Univ. of California Press.
Review by Mike Dubrasich
Twilight of the Mammoths is a first-person account of one of the greatest scientific discoveries of modern times, and that statement deserves some explanation.
In the main, Twilight of the Mammoths is about the Overkill Hypothesis. The end of the Ice Age saw the extinction of mammoths, mastodons, giant ground sloths, saber-toothed tigers, camels, horses, and all told, over 40 species and 30 genera of large mammals in the Western Hemisphere. These extinctions took place more or less contemporaneously with the arrival of the first humans, the Clovis People, approximately 13,000 calendar years ago. Dr. Martin hypothesizes that the two phenomena were linked, that paleo hunters decimated large mammal populations in North and South America within a few centuries (and perhaps in as little as 70 years after people first arrived).
But Twilight of the Mammoths is so much more than that.
The Overkill Hypothesis is a crude substitute for a much larger concept. Paul Martin should more properly be known as the Father of the Anthropogenic Predation Theory, which holds that human beings have been impacting wildlife populations for millennia, on all continents (except Antarctica), much as the Anthropogenic Fire Theory contends that humans have also been impacting terrestrial vegetation everywhere for a long time, too.
At their cores, the Anthropogenic Theories are an extension of Darwin’s Theory of Natural Selection. The principal selective agent in nature has been human beings for as long as we have existed on this planet. People have been driving natural selection, and hence evolution, wherever we have lived (13,000 years in the Western Hemisphere, 25,000+ years in Europe, 40,000+ years in Australia, 50,000+ years in Asia, and 100,000+ years in Africa).
A convincing case is made by Baz Edmeades in Megafauna—First Victims of the Human-Caused Extinction [here] that sapiens and pre-sapiens hominids in general have been the Keystone Predators and Masters of Fire in Africa for more than a million years. (Edmeades’ e-book is based ideas first presented by Dr. Martin, who wrote the Foreword to it.)
Darwinism changed the natural sciences. The Anthropogenic Extension of Darwinism is equally paradigm-shattering. Dr. Martin’s work is huge in terms of the Advancement of Science and the understanding of our world. As an early proponent of Anthropogenic Predation (his first writings on the subject were in the 1950’s), Paul Martin is a giant among scientists. Like Darwin, Martin’s work was also very controversial early on, but has been widely accepted for more than a decade by most archaeologists, geographers, natural historians and paleontologists. (Unfortunately, many modern wildlife and forest ecologists are still in the dark.)
To add icing to the cake, Twilight of the Mammoths is a first-person, popular account of a key scientific discovery, and that puts it in special company with John Imbrie’s Ice Ages: Solving the Mystery and James Watson’s The Double Helix. Dr. Martin is a polished writer with wit and incredible wisdom. Twilight of the Mammoths is a scientist’s memoir, in part, and very kind and good humored in that regard. It is also an exemplary presentation of deductive reasoning, a scientific detective story.
The first chapter in Twilight of the Mammoths is a review of Late Quaternary large mammal extinctions and the advent and critical scientific role of radiocarbon dating. There are tables and lists, and a huge amount of information, but it is very readable as well as fascinating.
The second chapter is a review of the Overkill Hypothesis. It is a masterful exposition:
To me the core piece of evidence for human involvement is that when viewed globally, near-time extinctions took place episodically, in a pattern not correlating with climatic change or any known factor other than the spread of our species. Extinctions followed prehistoric human colonization in a “deadly syncopation” to use the words of mammalogist Ross MacPhee. … Simply stated, as humans moved into different parts of the planet, many long-established huntable animals died out.
The best part of Twilight of the Mammoths is the rest of the book, though. In it Dr. Martin tells the story of a scientific detective gathering clues, making logical deductions, and piecing the truth together bit by bit. The detective is himself, and the story is his to tell, and it is remarkable. If you want to know how deductive science is done, Twilight of the Mammoths is the book to read.
It is a personal story, too, the life and times of a great scientist. Twilight of the Mammoths is very compelling in that regard, too.
Although Twilight of the Mammoths is mostly about animals, Dr. Martin included some interesting bits about forests:
Ponderosa is widespread today, ranging from the Sierra Madre Occidental of northern Mexico through the Southwest and the lower elevations of the Rocky Mountains into western Canada. In the last late or full glacial, it might well be expected to have occupied lower elevations in many parts of the West. Instead, the [packrat] middens suggest that it was absent from much of its modern range. Fossils of ponderosa pines more than 10,000 years old have yet to turn up in the midden record in the Grand Canyon (Cole 1990) or in glacial-age middens outside of Arizona. …
… The postglacial spread of ponderosa is so extraordinary that it challenges us to consider forcing functions beyond climate change. That is, did something happen to favor ponderosa after the last ice age, something in addition to the climactic warming that led most forest and woodland species to ascend in elevation? A major change in fire history, including season and intensity of firing, is one possibility. Ponderosas are fire-adapted. And with the arrival of people in the New World around the end of the last ice age, a change in wildfire frequency could be expected. Julio Betancourt (personal communication, December 2001) suggests that ponderosa pine benefited by fires set by Native Americans, artificial ignitions of relatively light intensity, set well in advance of the normal summer lightning strikes and ignitions. By removing excess fuel in advance of the season when firestorms are likely to develop, cool fires could have favored the ponderosas.
In the last two chapters in Twilight of the Mammoths, Dr. Martin advocates restoring some of the Pleistocene megafauna to North America. He would like to see mammoths, or their near equivalents in elephants, roaming again the parklands in the U.S. and Canada.
Twilight of the Mammoths is a keystone book in the annals of science history, and is destined to be a classic.
December 1, 2007 | Topic: Wildlife History
December 1st, 2007 at 7:51 pm
[Special Bonus: when I set out to write this post, I wrote to a friend and asked if he knew anything about Paul Martin. The friend put me in direct email contact, and Dr. Martin graciously sent this thumbnail autobiography. It is delightful, and I share the gift with you.]
Mike,
Did you get what you need for the bio bit? Here are my high spots. They may sound unconventional, but I did the best I could given a lifetime of lucky breaks. Being the only child of college educated, farm raised, middle aged, Anabaptist parents and born at the start of the presidency of Herbert Hoover helped. Don’t underestimate Sunday drives along the Brandywine with cannon from the American Revolution left as monuments and gypsies and hobos in the Pa. piedmont. At age 40 my Dad retrained himself at the University of Pennsylvania’s Veterinary College; fellow students in their 20s called him “Pops.”
In 1946 I went to Cornell to study ornithology (zoology), hoping to get to the tropics as soon as possible. In my Sophomore year I served as a field assistant to E. P. (Buck) Edwards when he worked on his thesis on the birds of the Lake Patzcuaro drainage in Michoacan, Mexico. We collected ducks on Lake Patzcuaro with Charles Sibley when Sibley was still a grad student at Berkeley.
Through kindness of the Canadian, Frank (Pancho) Harrison, I spent a month in southern Tamaulipas collecting birds for George Sutton in the then unknown Rancho del Cielo cloud forest with Liquidambar (sweet gum) and endemic oaks over 100 feet tall in the canopy. This is at the northern limit of the tropical conifer, Podocarpus; the forest attracted brocket deer (Mazama), jaguar, tinamou, guans and singing quail (Dactylortyx). The U. of Texas at Brownsville owns a field camp up there. The bedrock is cavernous Cretaceous limestone which harbored then undescribed species of plethodontid salamanders.
At the University of Michigan I “dissertated” on reptiles and amphibians of the Gomez Farias region (sea level to 8000 feet in southern Tamaulipas) at the University of Michigan’s Department of Zoology; where I debated late Quaternary extinctions of American megafauna with paleontologist Claude Hibbard and modeled overkill with the invaluable statistical treatment of James E. Mosiman.
The book you mention summarizes most of what I’ve learned and modeled for vertebrate extinctions in radiocarbon time, thanks in part to a postdoc at Yale with ecologist Ed Deevey where I learned Pleistocene pollen analysis with help of J. Iversen then on leave from the Danish Geological Survey.
On a postdoc summer in the Chiricahua Mountains of Arizona I discovered that there were fossil mammoths in alluvial deposits in southern Arizona at (some thought after) the end of the Pleistocene and a year later I won a job in the Geochronology Program at the University of Arizona after a postdoc at the Universite de Montreal in Quebec, Canada where I helped Gordon Lowther of McGill with an inter-University (McGill-Montreal) seminar on the Quaternary.
By then I was married with two kids and a third on the way. With an NSF grant I found a real job (from which I’m fully retired) at the University of Arizona’s Geochronology Labs off campus on Tumamoc Hill where my new boss, Ted Smiley, showed me the most extraordinary thing I had seen to date, the dung balls of the extinct Shasta Ground sloth from Rampart Cave in the Grand Canyon. Some of my travel was to make trips when I could, given the prognosis of a post-polio residual.
At the Desert Lab I taught courses in the Geochronology Department and soon had students that knew a good deal more than I had managed to learn about fossil pollen, extinct ice age animals, Quaternary geology and environmental education. One of them, Dave Steadman, has a new (2006) book (Univ. Chicago Press) on bird extinctions on oceanic islands, especially in the Pacific. The extinctions of island birds correlate very closely with the time of human arrivals. Guam Rails raised in captivity would restart rail evolution on ever so many islands where they were eliminated by Polynesian Rats. Don’t miss it.
I aspire to be a good natural historian especially attentive to change within radiocarbon time (last 40,000 years). I enjoy bird watching in my back yard in Tucson, and still get caught up in fierce arguments among misguided peers about what caused continental megafaunal and island bird extinction in radiocarbon time.
I’m amazed at the number of gainsayers that can’t or won’t see the overwhelming case for prehistoric people as the forcing function for large and many small mammal and bird extinctions, especially in the Americas in the last 40,000 years. It may not be an idea whose time has come, but it is certainly coming. For good reading don’t miss Tim Flannery’s books on the extinction story, especially the one he copyrighted in 2001 about extinctions in the United States. He had the Harvard postdoc targeted for Australians and requesting simply that the recipient write a book in return for the Fellowship.
– Paul S. Martin, Emeritus Professor of Geosciences, Desert Laboratory, University of Arizona.
PS: All this folds naturally into unconventional ideas about introduction of Afro-Asian megafauna from other continents into ours. In New Mexico a ranch is establishing Bolson tortoises that once lived north of the border and as you well know wild horses and burros may be doing too well in parts of the west. I was blown away by a visit several years ago to the “Equid Sanctuary” in northern New Mexico a vision if there ever was one into the North American Pleistocene.
Any suggestions or counter-arguments to the idea of returning Proboscidea to this Hemisphere? American elephants checked out only 13,000 calendar years ago, which is just about right for the arrival of Clovis Paleoindians. A change in fire frequency around then can certainly be considered. Archaeologists rooting for much earlier arrival of Homo sapiens hate the proposition that the chronology of human arrival might coincide with megafaunal extinction. I expected rough reviews of my Univ. Calif. Press (2005) book but most look good.
The bottom line? I continue to study megafaunal extinctions in radiocarbon time and try to keep abreast of new developments and wild visions in related fields. Charles Kay’s e-mails definitely help. His summary accounts of wolves are intriguing.
PPS: I rarely visit my office anymore but I take calls on my home phone. None of the above is copy-righted if anyone wants to know. A few e-mail responses would be welcome, if on target. Finally none of this message would have been possible without the collaboration of my spouse, Mary Kay O’Rourke. — Paul