The topic of dinosaurs, like space travel, strikes me as silly childhood fantasy, that is until I spend exactly 4 minutes learning about it and find myself wanting to devote my life to its study. The last time I thought about dinosaurs I was a kid. Like most thoughts I had when I was a kid, I do not trust them, as I am sure they were not based in reality. So I was happy to discover in a lecture series, “Behold, the Mighty Dinosaur” by Dr. John Kircher out of Wheaton University, that there were indeed extremely large and bizarre giant lizards that walked the earth. Yes; there really were 100 ton plant eaters. Yes; there were Stegosaurs that had giant bony plates along it’s back and spikes in it’s tail. Yes; they really did exist millions of years ago and were mysteriously wiped out.
What were they?
Dinosaurs were not lizards exactly. They did not drag their tales, like a crocodile as paleontologists used to think. We have found many dinosaur tracks, but no tail impressions. Instead they walked holding their tails in the air, usually balancing their neck and head straight out in front of them.
They were also were not slow moving or basking in the sun all day trying to heat themselves up. Instead, evidence now suggests that they were endothermic (warm-blooded) and lived very active lives. Alicia and I just went to the Colombo Zoo last weekend and, let me tell you as pedantically as possible, it is no fun to watch lizards. They don’t do shit. Monkeys, guinea pigs, and birds are great; they are constantly on the move, playing games, fighting, etc. Alicia and I even had a giraffe follow us around; we are pretty sure it liked white people for some reason (pictures to come later).
Dinosaurs have only one descendant that lives today, and that is birds. The ostrich is perhaps the closest thing we have to a dinosaur. (Check out Ostrich feet the next time you see them and think “dinosaur.”)
However, some of the big ones might have become more cold-blooded as they got bigger so as to substantially slow their metabolism. This would allow a dinosaur five times the size of a full-grown African elephant to only need the energy the elephant needed. In other words, on African safaris, we would see just as many animals, but they would all be bigger.
When were they?
This prof was a Wheaton professor, a good ole’ evangelical school, and he was telling me that dinosaurs lived between 65 million years ago and 245 million years ago. Many dinosaurs went extinct and evolved during that time; in fact a Tyrannosaurus Rex would have never battled a Stegosaurus, because the former was alive in the late Cretaceous and the latter in the Early Jurassic, nearly 100 million years apart.
To put this in perspective, Earth is guessed by scientists to be 4,500 million years old, but things did not get very interesting until 500 million years ago. After that vertebrates started coming (animals with spines), than land vertebrates, and then the dinosaurs, until 65 million years ago, when they suddenly disappeared from the fossil record. From then on exactly zero dinosaurs, except birds, appear in the sedimentary rock.
Why did dinosaurs suddenly and completely die off 65 million years ago.?
In addition to all non-avian dinosaurs, ammonites (type of mollusk), mosasaurs (large sea-faring reptiles), and many types of mammals went extint, along with plants, even a type of extremely plentiful sea amoeba.
There is evidence of two catastrophic events. The first is a series of volcanic eruptions called the Deccan Traps. You should know this word. Use it in poetry and you will sound cool…”My anger is a fiery tumult mightier than the Deccan Traps!” They are huge volcanoes which covered half of modern day India with lava flows and the whole world with dust and ash.
But the Deccan Traps’ numerous eruptions would have slowly affected the globe over millions of years, maybe even 8 million years (68-60 million years ago), which is not the sudden change that the fossil record shows. We also need something more harmful and more immediate, which points scientists to the Chicxulub impact.
65 million years ago a rock six miles across hit what is now the southern Gulf of Mexico with a force 2 million times bigger than the biggest ever detonated atomic bomb. It created a crater 112 miles in diameter. It would have immediately destroyed all life in the hemisphere; the T-Rex’s that ranged over North America were all dead right away; and covered that world in a cloud of soot and dust that poured acid rain, burned off the vegetation, and killed anything that was not small enough to hide—impact winter. It left a thin layer of sediment, the K-Pg Boundary, found all over the world with dinosaur fossils below it and none above it. It also contains high levels of Iridium, common on asteroids and not common on earth.
Whatever the Cretaceous–Paleogene extinction event was, it led to the rise of mammals, which had been living alongside the dinosaurs, but now had a wide open world to populate, and these mammals, apparently, led to us. Ironically, there were some smart dinosaurs that possibly could have evolved into intelligent creatures. Brain size roughly correlates with species’ intelligence, and there are some dinosaurs that had a brain to body ratio about halfway between dolphins and chimps and us. Were there dinosaurs capable of language? Would we have cities of dinosaurs now, with dinosaur presidents and dinosaur punk rockers?
And now for some random facts:
Dinosaurs were quite possibly extremely colorful. Many could have had feathers. Many could have had strange anatomical features which could not fossilize, like trunks or skin flaps.
Those big Sauropod plant eaters probably did not chew a thing. The only way their enormous bodies could be fed by such tiny heads is if they just stripped plants and swallowed. Smooth stones have been found in the rib cages that they think were swallowed to aid in digestion, like some birds do, like Ostriches, who can swallow stones up to 10 cm across.
Because these Sauropods were so enormous, we do not know why they had such long necks. They would have towered over most any tree that was around. My personal theory is simple: long necks were a big dinosaur turn-on.
The biggest flying dinosaur had a colossal 40 ft. wingspan. That blows my mind. It was an actual thing! Not some disney character.
Everyone who loves history has a moment when they realize how real history was; Napoleon and Thucydides was as real then as you or me are now. In the last week, I was simply overjoyed to discover that this Lost World of childhood fantasy turned out to be history. Dinosaurs really did live on this earth and roamed lands on which we all now tread—where we write and read blog posts. (I even categorized this post under ‘History.’)
And we still live in the age of giants. The biggest animal ever, at 180 tons, happens to be around today: the blue whale.