Contents Updated: Monday, September 13, 1999
"People could survive their natural trouble all right if it weren't for the trouble they make for themselves."
Charig, in his book, A New Look at the Dinosaurs, listed 30 likely causes of dinosaur extinction. He then listed less likely causes—poison gases, volcanic dust, meteorites, comets, sunspots and wars. Yet today, one of these, the meteorite or comet theory, is accepted by many as the unequivocal cause of the Cretaceous terminal event. An unlikely solution has become a certain solution. Why shouldn't it change again and favor instead poison gases and wars?
Perhaps the seeds of change are already germinating. Robert Bakker, we saw, is one of the authorities who do not accept the asteroid idea. Beverley Halstead of Reading University, England, who died in a road accident, was another.
Halstead had a brilliant but outrageous reputation. He once perched for a photograph naked in a tree, his genitals dangling below him. He also shocked and amused dinosaur enthusiasts at a conference by demonstrating with his girlfriend how dinosaurs could copulate despite their long tails. And Halstead believed that late Cretaceous dinosaurs did need help in reproducing—only twelve species remained when the end came.
Dinosaurs were already virtually extinct and had been in decline for five million years before the supposed fall of the asteroid.
Professor Anthony Hallam of Birmingham University, England, denies that an asteroid struck at all. Having closely examined the strata in the boundary layer, he believes that the iridium had been laid down over thousands of years, not a few months as a cosmic collision demanded. If the decline of the dinosaurs was associated with the iridium deposits, it was certainly not a sudden event.
What does seems indisputable is that many of the mechanisms of extinction reviewed in the last chapter and expected of a cosmic collision sound uncomfortably close to what we see about us today, the result of high technology and too many human beings demanding too much of the earth's resources with no thought of the consequences.
I have argued that the dinosaurs had the wherewithal to become intelligent. Did one species of dinosaur gradually kill off the others and finally itself?
Wilford doesn't think so.
Wondrous as they were the dinosaurs were limited. They were incapable of causing their own extinction, or of foreseeing and preventing it.
Yet today we are in the midst of a mass extinction before which that of the late Cretaceous seems to pale. Ecologist Norman Myers in his book, The Sinking Ark, warns us:
Basic processes of evolution are being altered more drastically than since the sudden disappearance of the dinosaurs, and possibly more than since the emergence of life's diversity
In the future, would our descendants or another intelligent species wonder about the mass extinctions at the end of the Tertiary? Would they notice our little conceit, the Quaternary—it would be only millimeters thick, like the K-T boundary layer? Would they realize that the extinctions had been caused by just one species, either deliberately or through carelessness?
Our record proves that we are killers. Perhaps the anthroposaurs were also.
We began killing other species a long time ago—and not just for food. Although mammoths, mastodons and woolly rhinoceroses had survived several periods of intense cold in previous cold phases of the present ice age, only at the end of the last one did they go extinct. A variety of catastrophic explanations for this have been suggested but, more likely is the simple explanation that they were hunted down by man.
The Miocene period of about 20 million years ago was the age of the apes. Today only five species, including man, remain. Only man is populous. Don Johanson and Maitland Edey say:
We are responsible for the disasters that have recently overtaken all modern apes.
Carl Sagan is more explicit:
Humans have systematically exterminated those other primates who have displayed signs of intelligence... We may have been the agents of natural selection in suppressing the intellectual competition.
We have confined the gorilla, the chimpanzee, the orangutan and the gibbon to narrow areas and within our lifetime they could be extinct. We will have murdered our intellectual rivals.
More obvious intellectual rivals had already been disposed of by our ancestors.
The dismembered remains of 50 adult giant baboons and several juveniles were unearthed at Olongesailie in South West Kenya. With them were hundreds of chipped stones from a site 20 miles away. Clues that tool-users brandishing weapons killed these animals comes from the presence of percussion flakes from toolmaking and cut marks on the bones. Baboons are powerful animals. With their strong jaws they do not need to make stone tools. They also live in bands. The hunter that had disposed of them must have been skillful and far from cowardly. He apparently had only primitive tools to face ferocious troops of giant baboons. The hunter was the first true man, Homo erectus—the giant baboon is long extinct.
Anthropologists have found stone tool fragments alongside Australopithecus remains suggesting that A.africanus was the tool maker. But the stone flakes are the same as those made by Homo erectus. The implements found with the australopithecine bones were discarded by Homo erectus after dinner. The australopithecines were extinct 1.4 million years ago, caught between the predatory attentions of Homo who found them easy game (just as slow as Homo was himself and too unsophisticated to defend themselves adequately) and the baboons who had no particular predatory intentions but competed more successfully for food.
About two million years ago mammalian evolution went into overdrive and the number of genera of mammals trebled in the next million years. The diversity of mammals peaked about one million years ago. Since then it has continuously declined as mankind became increasingly dominant. Most mammals other than domestic animals will be extinct within decades.
Compare it with the Cretaceous. Bakker writes:
It took no more than two million years—maybe much less—to exterminate the dinosaurs.
The prehistory of mankind has many examples of apparently unnecessary killing. Were men even in those early days as insensitive to other species as they appear to be today?
At the foot of a limestone cliff at Solutre, France, was a 50 feet deep mound of horse bones, killed by prehistoric man. Dr Sandra Olsen of the John Hopkins Medical Institute, Baltimore, examined the remains of animals killed by early man on sites like this, 35,000 years old, and showed that only seven of 3000 bones, mainly reindeer, had cut marks on them caused by butchery. So few signs of cutting could only signify that prehistoric men had not killed these animals primarily for meat. The experts decided they had killed for delicacies—liver and intestines. Maybe. Or maybe they just killed for fun! Maybe they got high on the smell of death. At any rate the slaughter continued for 25,000 years.
Carl Sagan tells us:
Shortly after man entered North America via the Bering Straits there were massive and spectacular kills of large game animals, often by driving them over cliffs.
Like their contemporaries at Solutre, these emergent men used the same technique, but thousands of miles away. Mass carnage was widespread and effective.