Dinosaurs were a diverse and successful group of animals whose remains have fascinated us and inspired myths that persist into modern times. Although the last dinosaur died 63 million years before the first human, some stories infer contemporaneous existence or defy the fact of their demise. Behind these narrative relationships may lie an innate interest in what ended the reign of such successful creatures, as realization grows that humans are not exempt from similar factors causing their own fate.
Dinosaurs beheld the world long before humans. They evolved 230 million years ago on the single continent that was then the land surface of the earth. As the pieces of Pangaea separated and slowly drifted apart, their descendants were carried across the surface of the globe to become a hugely diverse and successful force of terrestrial ecology. They left traces of their existence on every continent, fossilized as tracks or bones preserved by geological accident. After a 165-million-year reign on earth, they suffered an abrupt demise, leaving their feathered descendants to fly over a world that was now safe for mammals. It would be another 58 million years until the first hominids appeared in present-day Africa, and a further 6 million years before our genus Homo could gaze upon the fossilized traces, and wonder . . .
Dinosaurs have long held deep fascination for humans. Their large and strange bones, continuously being exposed naturally by erosion, were encountered with amazement by ancient peoples. With no concept that animals once alive may have become extinct, speculation on the obviously dangerous creature that must visit from somewhere over the horizon inspired imagination and fear, and thus were born mythological creatures such as dragons, griffins, and winged serpents. Noting the similarity of sharp teeth and long tails of some dinosaur skeletons to familiar animals, depictions of dragons carried heads like a lion and bodies of snakelike form. Commonly, these reconstructions had wings, a not-too-inaccurate reconstruction of some dinosaurs that share close ancestry with birds. The additional inference of flight explained how the mythological creature could travel between its unseen lair and the local environment where its mortal remains lay.
These mythological explanations were later supplanted by formal religious beliefs, as in the Genesis account of the creation. Rational thought on how organisms can develop, change, and end would precipitate only in the last three centuries of human evolution. Yet stories and myth about humans and dinosaurs coexisting persist in some countries.
In central Africa and South America, legends tell of “Mokelembembe,” alluding to a still-living sauropod dinosaur, while in Europe, local myths infer other creatures left over from the Mesozoic age of dinosaurs are still rearing their heads. The purveyors of these stories do not seem to consider that animals cannot live forever as individuals; a herd of dinosaurs large enough to form a sustainable breeding population this last 65 million years would be hard to miss even in the jungles of Congo, never mind around the tourist-tramped shores of Scottish Loch Ness.
In North America, supposedly human footprint traces are claimed to occur with those of dinosaurs at a small number of dinosaur track sites. Studies have revealed that the claimed human prints are in fact misidentified dinosaur tracks, natural erosions, or carvings by hoaxers and others with vested interests in myth. In some locales, there have arisen small industries to perpetuate and trade on such stories, sustaining fundraising from tourism and religious cultures.
In thousands of excavations around the world, on every continent, while recovering fossils and traces of tens of thousands of species of flora and fauna, no dinosaur and human remains have ever been found together to suggest any contemporaneous existence. The gap in time between the last dinosaurs to the earliest human being is approximately 30 times that of the entire existence of humans on the planet: The earliest Homo remains date to about 2 million years ago, and you have to travel 30 times that number further back in time to the last of the dinosaurs. This gap of 63 million years dwarfs the short history of human evolution and is a vast ocean across which no contemporaneous existence can cross. Even human myth must at some stage be diluted by the fact that the dinosaurs are gone forever.
After 165 million years of terrestrial domination, the dinosaurs became extinct at the end of the Cretaceous period during the most notorious of five mass extinction events in life’s history. They were a major group but only one of a large percentage of the world’s flora and fauna that became extinct in a profound turnover of the earth’s biota at that time. And what unfortunate series of events conspired to overcome the hitherto successful dinosaurs? Arguments continue to rage. There was massive volcanism and widespread marine regression toward the end of the Cretaceous, but the rate and scale of change these would have imposed on climate and environment is unclear. The evidence for the publicly popular theory of meteorite impact is well supported, with the necessary-size crater and over 110 sites documented with evidence of impact fallout such as Iridium and shocked quartz, yet the size and tempo of stresses this would induce upon life are hard to model.
Each hypothesis has its own complex mechanisms and interactions to explain the results seen in the fossil record. The anomalies in the patterns of surviving taxa are difficult to explain by a single theory, such as why birds survived while pterosaurs did not; so arguments as to the type and tempo of causes and mechanisms continue. There may be growing consensus that the patterns of extinction and survival indicate a more complex scenario than a single event might suggest, such as a combination of events causing a stressful rate of environmental change, with the meteorite impact being the coup de grace upon an already worsening fitness landscape. Although an exact and complete answer to the question of dinosaur extinction is yet to be ascertained, the discovery of the complexity of mechanisms involved has led to growing realizations about extinction processes and what they may look like in the modern world.
Underlying our continued fascination with dinosaurs as excitingly different creatures is a more fundamental and serious need. For humans may be naturally curious, as befits our mammalian development, but we also have a primal drive for answers to potentially fatal questions. What dangers can we expect to find in our own fitness landscapes, and what will they look like at an early stage? Are we adapting to evolutionary pressures successfully, and if not, what will signs of our own demise look like?
Dinosaurs, as robust fossils of great diversity over a long period of time, provide a useful record of life history with which to compare our own progress. There is increased awareness that humans too have to navigate the same evolutionary pressures that descended upon the dinosaurs and caused the demise of their once mighty branch of life. In this way, dinosaurs provide us with more than myth and movies, and are also illuminating the potential paths of development that humans must travel to become exempt from the same evolutionary fate.
- Dawkins, R. (2004). The ancestors’ tale: A pilgrimage to the dawn of life. London: Weidenfeld & Nicolson.
- McGowan, C. (2001). The dragon seekers: How an extraordinary circle of fossilists discovered the dinosaurs and paved the way for Darwin. Cambridge, MA: Perseus.
- Spalding, D. (1993). Dinosaur hunters: 150years of extraordinary discoveries. Toronto, Canada: Key Porter Books.
- Weishampel, D., Dodson, P., & Osmolska, H. (Eds.). (2004). The dinosaurian (2nd ed.). Berkeley: University of California Press.