Dinosaurs: Tyrannosaurus Rex
Staring Into The Face Of Death
One Fearsome Female
What T-Rex May Have Looked Like
T-Rex On The Attack
From the myths of King Gilgamesh, the fifth Sumerian ruler, to the stories of ancient Greece, monsters, such as the giant one eyed Cyclops and the multi headed Hydra, have been a constant reminder of the vulnerability of man and his artifice against the force of nature.
Imagine the surprise of Western naturalists and scientists then, when incontrovertible evidence began to emerge in the early nineteenth century that enormous monsters really did once roam and indeed rule the Earth. Fiction became fact. And what of the possibility that humans, following on from Darwin’s deductions were themselves descended from creatures such as these? To most people living then, the very idea was, well…monstrous.
Today evidence for the existence of now extinct giant lizards called dinosaurs is universally accepted. Fossilised bones have often been exquisitely preserved in the rocks, allowing experts to piece back together the precise shape and form of these creatures that once ruled the world. Although extinct for more than sixty five million years (apart from the birds), dinosaurs had a profound impact on the planet, life and people that lives on today.
Some trees turned the threat of being eaten into an opportunity. They effectively bribed the giant roaming herbivores such as Diplodocus by wrapping their seeds in a juicy meal, a packaging system that we call fruit. At an enormous 92 pounds the mature buttock shaped sea coconut (the fruit of a coco de mer tree) evolved into a form that was attractive to peckish dinosaurs. These dinosaurs would then spread the seeds in their dung. A few of these ancient palms still grow in Madagascar, Malaysia and New Guinea today. Owing to the demise of the dinosaurs, however, these species are long past their prime.
Meanwhile, other trees established elaborate techniques for defence, such as the maze of branches of the monkey puzzle tree. A group of plants called monocots even learned to grow ‘upside down’, keeping their buds hidden beneath the ground to prevent grazing dinosaurs from eating the newest, freshest grown first. These species evolved into grasses and palms that have also transformed the world.
An Iconic Moment In An Iconic Film
More On Tyrannosaurus Rex
The most successful dinosaur group of all was the theropods. Not only were these among the first dinosaurs to have emerged, about 230 million years ago but they are the only surviving branch of dinosaurs to exist today. Birds, with their common theropod characteristics of wishbones and three toed feet, are this group’s living descendants. The rest disappeared in a giant mass extinction 65 million years ago, the same catastrophe that finished off all the other dinosaurs, as well as the pterosaurs and giant marine reptiles.
The most fearful theropod, and by far the most famous dinosaur fossil, was Tyrannosaurus rex- a gruesome creature that lived between 75 and 65 million years ago in North America and Canada. Other similar creatures such as Tarbosaurus, roamed the forests of East Asia, while Allosaurus and Giganotosaurus lived in South America. Collectively, these dinosaurs must have created a climate of fear among other vertebrate animals during the Jurassic and Cretaceous Periods.
Anyone living close to Chicago, in the US, can get a good first hand impression of the sheer size and power of creatures like these by taking a trip to the city’s Field Museum. Here the largest and most complete fossilised T.rex skeleton is to be found. She is named Sue, after Sue Hendrickson who discovered her in 1990 near the Cheyenne River Indian Reservation in western South Dakota. Sue clearly shows why the Tyrannosaurus was such a fearsome creature, with bone crushing jaws more than 4 feet long and 3 feet wide. Its individual teeth were curved and serrated, many of them longer than a human hand, allowing the beast to crush its victims to death almost instantaneously, swallowing up to 150 pounds of meat in one go.
Key to these creatures’ success was a fully improved stance that meant their entire weight was taken on their hind legs, allowing them to balance effectively on two feet and increasing their manoeuvrability despite their enormous body size (40 feet long).
The Moment That T-Rex's World Ended
Extinction And Legacy
The devastating event that killed off all of the dinosaurs 65 million years ago, including T.rex, was probably the chance impact of a 6 mile wide meteorite. This cataclysm plunged the Earth’s climate and atmosphere into a new dark age where luck, not evolutionary fitness, became the main criterion separating survival from extinction. Large terrestrial reptiles were most at risk, especially those that fed on flesh. As populations plummeted, food became scarce. If the actual impact or climate didn't kill off T-rex, then starvation certainly must have finished the job.
Yet long after their demise, the impact of theropods like Tyrannosaurus continues to reverberate in the shape, form and function of the biological world today.
Living alongside Tyrannosaurus and the other giant dinosaurs were creatures that survived and thrived by staying small and remaining hidden in the woods and trees. These were little, shrew like mammals, which spent time protecting their young, and benefited from a covering of fur to keep their bodies warm so they could hunt at night when there was less threat of attack by theropod monsters.
Fertilised eggs that grow inside the mother’s body were other adaptations that ultimately evolved in many mammals as a direct response to the threat posed by dinosaurs (including birds and pterosaurs) that regularly helped themselves to eggs. Mammals were oviparous, in other words they gave birth to live young. They also possessed mammary or milk producing glands, which meant that females did not have to leave their nests to find food for their young until it was safe to do so. In a world dominated by giant flesh eaters like T. rex, mammary glands evolved as an essential component of the mammals’ Jurassic survival kit.