Thanks to Damian, who suggested T. rex as a topic! Let’s learn all about the T. rex and especially the most famous and controversial specimen ever found, Sue.

A T. rex:

Sue, also a T. rex:

Show transcript:

Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.

Our topic this week is a suggestion from Damian, who wants to hear about the one, the only, the tyrant lizard king with massive everything except arms, Tyrannosaurus rex. Aw yeah

You probably know a lot about T. rex without realizing it. It’s THE dinosaur, the one people think of first when you say dinosaur. But a lot of popular knowledge about the T. rex is actually out of date, so let’s find out what’s really going on with that big toothy theropod.

First of all, T. rex did not live in the Jurassic period. It lived much later, in the late Cretaceous, around 66 million years ago. But I guess Late Cretaceous Park doesn’t have quite the same ring to it. It was one of the last non-avian dinosaurs, dying off in the Cretaceous-Paleogene extinction. It lived in what is now western North America, with close relatives in many other parts of the world.

T. rex was a big animal, no doubt about it. The biggest individual we know of, called Sue, stood around 12 feet tall, or a little over 3 ½ meters at the hips. The weight of its massive head was balanced by its long tail. Nose to tail it was around 40 feet long, or about 12 meters. Plenty of other dinosaurs were bigger than T. rex, but T. rex was the biggest land predator we know of.

While T. rex had long legs, its arms are famously teeny, only about three feet long, or one meter. That’s barely longer than an adult human’s arm. But recent research shows that the arms weren’t weak. The bones were strong and so were the muscles, although the arm had a limited range of motion and only two toes. Many researchers think T rex used its arms to hold onto struggling prey.

Since all we have are fossils, we don’t really know what T. rex looked like beyond its bones and muscles, which we know about from study of muscle attachment sites on the bones. Some researchers think it probably had at least some feathers, since we have feather impressions from some of T rex’s close relations. Baby T rex might have had feathers and shed them as it grew up, or it might have had feathers its whole life. We have fossilized skin impressions from a specimen found in 2002 that show scales on the tail, neck, and hip, so many researchers suggest that T rex only had feathers on its head and back, possibly for decoration or protection from the elements. Closely related species show feather impressions over all of the body, so we know T rex’s cousins were feathered.

We also know that T rex had large flat scales on its snout with patches of keratin in the middle, which probably contained sensory bundles. These same patches are present in crocodilians, which help crocs move their eggs and babies without harming them, and help them sense the temperature of their nests.

In 2016, researchers discovered that T rex’s teeth contained enamel. This makes the teeth harder, but enamel has to stay damp. That means T rex probably had lips and its teeth wouldn’t have been visible except when the mouth was open. If that sounds weird, most reptiles have lips. Crocodilians don’t, so some of their teeth show when their mouths are closed, but they also live in the water so don’t have to worry about dry mouth.

Just to be clear, reptile lips aren’t big kissy lips. They’re just skin that allows the teeth to be completely enclosed within the mouth when the jaws are closed, keeping the mouth from drying out.

In 2005, paleontologist Mary Schweitzer found soft tissue in the femur, or thigh bone, of a 68 million year old T rex. The tissue contained blood vessels and a substance called medullary bone, which is only present in female birds right before they lay eggs. Medullary bone helps the bird’s body make shells for her eggs. Since then, researchers have found soft tissue within bones of two more T rexes and a hadrosaur. They’re not yet sure how the soft tissue was preserved. The blood vessels resemble those of ostriches more than they resemble crocodilian blood vessels.

For a long time scientists thought that dinosaurs like T rex stood upright with the tail acting as a prop. You know, sort of like Barney. This was recognized as wrong by around the 1970s, but paleontologists are still figuring out the details about how T rex moved around. For instance, we still don’t know if T rex could run. Many researchers now think it probably could, although it might not have been able to run faster than around 25 mph, or 40 km/h. That’s about the speed of a human sprinter. Some of T rex’s bones are hollow to reduce weight, and its feet show adaptations to withstand stresses. But we don’t know for sure, and studies continue using ever more sophisticated mathematical models.

We also don’t know if T rex was warmblooded like birds, or cold-blooded like reptiles. Considering its close relationship to birds, many researchers think it was warm-blooded, properly called endothermic. An endothermic animal can regulate its body temperature internally regardless of the air temperature.

T rex had excellent vision and sense of smell. It could hear very well too, especially low-frequency sounds. It had a massively strong bite, probably the strongest bite force of any land animal. Its bite could crush bone. It would have been a deadly hunter but probably also scavenged, either by stealing kills from other predators or eating anything dead it came across.

We have fossils that show damage from T rex bites, including to other T rexes. It’s possible T rexes fought, either over food or mates, or that bigger T rexes sometimes ate smaller ones. All T rex remains show damage, though, since the life of a predator is a tough one, and the bigger the animals you hunt, the more damage you’re going to take.

So that’s a lot of up-to-date information about Tyrannosaurus rex, or as up-to-date as I could find. Lots of paleontologists are studying T rex, so more information gets published all the time. While I was researching, though, I kept running across interesting details about the specimen nicknamed Sue.

Sue was discovered in August 1990 in South Dakota, on the Cheyenne River Indian Reservation, by paleontologist Sue Hendrickson. It was the last day of the dig and in fact the group was about to head home with a bunch of Edmontosaurus fossils when they noticed their truck had a flat tire. While the tire was getting changed, Sue Hendrickson took the opportunity to poke around for any last-minute fossils. She spotted some loose bones that had weathered out of a cliff, and saw bigger bones sticking out of the cliff above her, so she took the loose bones back to the dig supervisor and president of the Black Hills Institute, Peter Larson. Larson recognized them as T rex bones and immediately decided they weren’t going to leave that day after all.

It was a good decision, because once the bones were excavated, it turned out to be not only the biggest T rex skeleton ever discovered, but the most complete, and in excellent condition.

The group took the fossils back to the Black Hills Institute to clean and prepare them, and that should have been that. But unfortunately, T rex remains are worth a lot of money and that caused issues almost immediately.

The Black Hills Institute had gotten permission to excavate Sue the dinosaur, and had paid the landowner $5,000. The land was owned by Maurice Williams, a member of the Sioux tribe, and since his land was also part of the Sioux reservation, the tribe said the fossils belonged to the tribe, not just Williams.

It’s easy to think of Williams as greedy, but the situation was far more complicated than it sounds. Peter Larson’s group weren’t just in it for the science. They were commercial bone hunters, which means they would have sold the T rex fossil after it was prepared and kept all the money. They had already started taking offers for the sale when Williams sued. Not only that, Williams’s land was held in trust by the government, which meant Larson was supposed to get permission from not just Maurice Williams but the Department of the Interior to excavate fossils on the land, and he hadn’t even asked.

It was a lengthy, complicated trial. Even the FBI had to get involved. They and the South Dakota National Guard seized the fossils and kept them in storage until the trial ended. Peter Larson was charged with fossil theft—not of Sue the T rex, but of other fossils that didn’t have anything to do with Williams. He was found guilty of theft of fossils from public land and lying on customs documents about fossil deals in Peru and Japan, and spent 18 months in jail.

The court decided that Maurice Williams did own the fossils. Williams contacted the auction house Sotheby’s to sell them.

The paleontological community panicked at this, because when I say T rex fossils are worth a lot of money, I don’t mean it’s just scientists who fight each other to buy them. I mean rich people want them for private collections. Fossils in private collections are usually never studied, so they’re nothing more than decorations and don’t add anything to our collective knowledge of creatures that lived in the past. There’s nothing wrong with owning fossils of common animals, of course, but when it’s an important find like this one, it needs to be prepared properly, studied by experts all over the world, and put on public display.

So the Chicago Field Museum of Natural History scrambled to find funding to bid on the T rex. They asked lots of companies and individuals to donate, and those companies and individuals stepped up—companies like McDonald’s and Walt Disney Parks, so good for them.

The auction was held in October 1997. The starting bid was $500,000. At the time, the top amount paid for a fossil had been around $600,000, but Sotheby’s expected this sale to top one million. We don’t know who bid because Sotheby’s keeps this information a secret, but we do know that the Smithsonian had been prepared to spend 2 ½ million.

The auction only lasted eight minutes and the Field Museum won. It paid $8.3 million dollars for Sue the T rex, of which 7.6 million went to Williams. Disney was given a replica of Sue’s skeleton for display and McDonald’s was given two replicas.

It’s great that Sue was bought by an institution that has made the fossil available for study and put it on permanent display to the public. But because the auction went for so much, and was so well publicized, it had some negative repercussions. For a few years after the auction, all fossil auctions were much higher than before, stretching museum budgets to the limits. It is now much harder for paleontologists to get permission to dig on private property, and people started stealing fossils from dig sites, thinking they might get rich.

Williams was fined for selling dinosaur bones without a business license. He died in 2011 at the age of 85and I couldn’t find out what he did with the money he received from the auction, but apparently he kept it in his family and did not donate any to his tribe. While the Cheyenne River tribe’s policy is to leave fossils undisturbed, the nearby Standing Rock Reservation has its own paleontology department and museum. The group visits local schools to give presentations on dinosaurs found in the area.

In 2002 Larson and his then-wife, Kristin Donnan, published a book called Rex Appeal, and in 2014 made a documentary from the book called Dinosaur 13. Critics have pointed out that both book and film tell a one-sided story, painting Larson as an innocent who was wronged by the system and ignoring Williams’s point of view entirely.

It sounds like Williams was actually kind of a jerk. But it also sounds like Larson was kind of a jerk. People get weird when a lot of money is on the line, and at least Larson truly loves paleontology and has contributed a lot to the field—you know, when he’s not selling fossils to private collectors.

As for Sue the T rex, we don’t actually know if the dinosaur was male or female, but it usually gets referred to as a she because it’s named after Sue Hendrickson, the discoverer. Sue the T rex has been studied extensively so we know a lot about her. She was 28 years old when she died and had arthritis in her tail, had recovered from some serious injuries including broken ribs and a torn tendon in her right arm, and her skull shows pathology that might have killed her. Some researchers think Sue died from a parasitic infection from eating diseased meat. Modern birds sometimes contract what may be the same parasite, which causes swelling of the throat that ultimately starves the bird to death.

A few months ago as of this recording, in February of 2018, Sue was dismantled and removed temporarily from display so that some missing small bones can be added to the skeleton and adjustments made to her posture. She will then be moved to her own room in the Field Museum in 2019. Sue also has her own Twitter account, @SUEtheTrex. It’s actually pretty funny. I just followed it.

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Thanks for listening!