Monthly Archives: July 2010

Tyrannosaurus rex

In the long, often boring, and generally disappointing history of evolution, nothing has managed to capture our imagination quite like the dinosaurs.1 The simple fact that there were once giant, terrifying reptiles with tiny brains who “ruled the Earth”2 is enough to inspire awe, but that they then disappeared prior to the invention of the camera phone really compounds it. On the cosmic scale of things, the fact that grizzly bears frighten us is a bit laughable, for if they stepped out of a time machine and into the age of the dinosaurs, grizzly bears would spend the majority of their short lives screaming like children and running away from everything they saw – including the plants, probably – and wondering what the hell was going on here (and also kicking themselves for not just stopping the time machine in 1929 and shorting the stock market, like they had planned).

‘I’m short oil, I’m short steel, I’m short railroads…I’m short pretty much everything. Oh, I’m from the future.’

Of all the dinosaurs, none is so iconic as Tyrannosaurus rex (lit. ‘Tyrant-Lizard King (not the band)’). Hailing from the late Cretaceous between 85 and 65 million years ago, Tyrannosaurus rex (or T. rex, as it preferred to be called), was, from what we can suss out based on skeletal remains, one of the largest carnivores ever, standing 15 feet tall, reaching up to 40 feet long, and weighing somewhere around 7,000 pounds. According to people who estimate things that are impossible to estimate, its 700 pound head could, with the aid of serrated teeth the size of bananas, tear off up to 500 pounds of meat in a single bite. But what’s most breathtaking about T. rex was that it was, at one point, real. T. rexes roamed Western North America for millions of years, and in a time when dinosaurs ruled, they were king.

‘More mead and serving wenches! And tell my younger brother to calm down. I can’t handle his psychodrama right now.’

Or so we’re led to believe. The truth is that everything we know about T. rex comes from fossilized remains – reptilian bone slowly replaced by minerals over the course of millions of years – and a few Spielberg movies. And from these sources, our best and brightest scientists can only make rough deductions about T. rex based on a knowledge of biomechanics and animal anatomy comparisons drawn from extant fauna. What this means is that, while it certainly looked like a carnivorous tyrant-lizard king, for all we really know, T. rex actually liked eating flowers and hugging. Only one thing is for sure—leaving behind a giant skeleton with massive teeth the size of bananas is a surefire way to get lots of kids books written about yourself.

His one wish was that some future species educate their offspring about his work.

As with all other dinosaurs, there are no T. rexes frozen in ice (unlike the wooly mammoth), no T. rex photographs, no T. rex audio recordings, and only the crudest of T. rex diary entries, leaving a vast chasm of T. rex knowledge that is open to interpretation, speculation, and prolific grant-writing by bearded paleontologists who spend their adult lives hoping that PBS interviews them in their Indiana Jones hat at least once.

‘Believe it or not, I’m a bit of a rebel. I mean, I got the hat and everything.’

For instance, some paleontologists believe that all tyrannosaurs, including T. rex, must have been covered in feathers at some point during their life cycles (most likely after hatching). If nothing else, a feather-covered T. rex was surely a lot less intimidating, not to mention a lot more upsetting for his dad. But we don’t know. We also don’t know whether T. rex was a hunter or a scavenger. While a massive dinosaur with a mouthful of banana teeth that could deliver a bite with 1440 pounds of force in the front part of its jaw and 3011 in the back would seem to be a bit of a no-brainer in the hunting department, some paleontologists suggest that their massive legs may have prevented them from running as fast as their potential prey (biomechanics pins their top speed at about 18 mph, which is slightly faster than a human being can run). They also had relatively large olfactory lobes, which could (could!) mean a powerful sense of smell for locating rotten meat (similar to New World vultures, which are award-winning, world-class scavengers). And then, of course, there was the issue of T. rex’s hilariously undersized forearms, which could not even reach their own mouth (meaning that, however they got their food, they never wiped their mouth after dinner). These almost vestigial forearms were likely little use for grasping prey, and they were almost certainly worthless in push up contests.

‘Well they’ll work just fine for Xbox. When’s that coming out again?’

But others dissent from this view and remain convinced T. rex was a hunter, pointing to its stereoscopic vision (and, you know, the spiky banana teeth). Still others think the shreds of rotten, bacteria-infested meat lodged in its numerous teeth gave T. rex a “septic bite,” which caused an initial bite wound to become infected, making these tyrannosaurs among the very first bioterrorists. And, for what it’s worth, this would also explain why two T. rex fossils have never been found locked in a passionate kiss.

The most complete T. rex skeleton ever found was discovered in South Dakota in 1990. Currently on display at the Field Museum in Chicago, ‘Sue’ has shed a great deal of new light on the Tyrannosaurus rex. For instance, we now know that we don’t know whether Sue was a male or a female. We do know, however, that Sue died at some point in what is now South Dakota. Probably. For all we know, she or he passed away in what is now Montana, but the other T. rexes brought her to South Dakota for an incredibly elaborate funeral procession that featured a full marching band and several push up contests.

‘By the way, I was also pink. Everything was. Long story.’

However, using a little bit of common sense, we can probably make the reasonable leap and conclude that T. rex was a hunter; after all, T. rex-esque wounds have been found in other dinosaur skeletons. Of course, these may have been inflicted post-mortem. But let’s be honest–does anyone think that something with banana teeth and a brain smaller than a quart of milk was reluctant to bite anything and everything around it?

Obviously, grading an animal that no longer exists – and about whom so much remains murky – presents a challenge. But after much meditation and consideration, one is stuck with the words ‘banana teeth,’ and grading T. rex, unlike every other aspect of its investigation, becomes quite simple.


1 The notable exception being the great white shark.

2 A small minority of experts think that the dinosaurs were brought down by an overextended state budget, bread riots, an overreliance on mercenaries, and general internal decadence. This minority is very, very small.