Today, we talk about dragons, jackals, and survival
of the species. The University of Houston's College
of Engineering presents this series about the
machines that make our civilization run, and the
people whose ingenuity created them.
Two complete Tyrannosaurus
rex skeletons recently turned up in Montana and in
South Dakota. That's good news, because he's one of
the less known of the great dinosaurs. 'Til now,
his remains have been few and fragmentary. That
monster has eluded our understanding.
Was he a predator or a scavenger? He certainly was
a meat-eater, but did he hunt other dinosaurs? Or
did this seemingly ferocious beast just feed on the
weak and recently dead?
Remember what Tyrannosaurus looked like. He was
over forty feet long, with powerful hind legs and
tail. He had a great mandible of a jaw with vicious
teeth. But his arms were pitifully short. It's
clear he couldn't run. He was ill-equipped to chase
his supper. Perhaps Tyrannosaurus rex was no Tyrant
king after all. Maybe he was only a jackal.
Another view lurks in dinosaur lore. It is that
these great lizards were slow-witted and badly
equipped for survival and that they died out. Well,
they did die out, but only after they'd survived on
this earth for 100 million years. That's fifty
times longer than we've been around. Right now, few
people are betting we'll still be here 98 million
years from now.
When the dinosaurs did die out, it wasn't because
they were badly adapted. More likely it was some
external cataclysm. Maybe a large meteor impact
dramatically changed the ecology.
As for intelligence? Well, no one's ever given a
dinosaur an IQ test. What we know about is the size
of their brains. The larger any beast is, the
larger its brain is. But brains don't increase in
size as rapidly as bodies. The ratio of brain to
body weight is far less in an elephant than it is
in a mouse.
Actually, dinosaurs' brains are about the size we'd
expect for such huge lizards. Vegetarian dinosaurs
had less brain than meat-eaters. Some
Tyrannosauruses had twice the brain we'd expect.
Some grazing dinosaurs -- only a third.
So Tyrannosaurus had a predator's mental agility.
Now these new skeletons show us something more. His
tiny arms were remarkably strong. He could lift
over a ton. The skeletons say little about his
tactics. But all the signs point to a better
adapted and more frightening foe than we'd thought.
So we struggle with a smaller question and find
ourselves answering larger ones. Was Tyrannosaurus
a predator? Maybe he was after all. He and his
scaly friends were certainly better adapted than we
thought. And seeing these ancient kinfolk clearly
reminds us how fragile our own claim to survival
might be.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds
work.
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