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DR PHILIP J CURRIE’S NEW SCIENCE OF DINOSAURS

Dino Gangs
By Josh Young

This book is dedicated to those children whose eyes grow as big as saucers when they see their first dinosaur exhibit, and then follow that passion into a career in dinosaur palaeontology.

Contents

Cover

Title Page

Introduction

The Terrible Lizards

Chapter 1

The World of Dinosaurs

Chapter 2

The Dino Hunters

Chapter 3

The Badlands of Canada

Chapter 4

The Gobi Desert

Chapter 5

A Dinosaur Dig

Chapter 6

To the Lab … and Beyond

Chapter 7

Speedy Creatures

Chapter 8

Scavenger or Predator?

Chapter 9

Dinosaur Intelligence

Chapter 10

The Dino Gang Theory Comes to Life

Epilogue

Dinosaurs Live On

Searchable Terms

Acknowledgements

Copyright

About the Publisher

introduction
the terrible lizards

As the monsters of our nightmares, dinosaurs have long held a unique place in our fascination with ancient animals. Even though dinosaurs lived millions of years ago, they somehow seem very real – and very scary. Anyone who has seen a museum exhibit of a mounted dinosaur skeleton cannot help but be awed by the sheer size of some dinosaurs and the bizarre features of others. Dinosaurs have been used to market everything from sweets and breakfast cereal to petrol and pasta, and they have been featured in movies and books as demonic dragons. Much of what we know about dinosaurs comes from how they are portrayed in books, movies and popular culture.

The term ‘dinosaur’ was coined in 1842 by the British palaeontologist Richard Owen. It was derived from the Greek words deinos, meaning ‘terrible’, and sauros, meaning ‘lizard’. Not long after dinosaurs were scientifically identified, Charles Dickens introduced a Megalosaurus in the opening paragraph of his 1853 novel Bleak House as something one would not want to see walking up the street. In his popular 1912 novel The Lost World, Sir Arthur Conan Doyle, creator of Sherlock Holmes, set out a scenario under which dinosaurs ruled a tropical paradise in South America. Edgar Rice Burroughs used them repeatedly in his ‘lost world’ stories and featured them on the cover of his 1924 novel The Land That Time Forgot. The cinema brought dinosaurs to life in the classic monster movies King Kong and Godzilla. Indeed Godzilla was created to look like a large dinosaur, with its massive head and lower body resembling that of a Tyrannosaurus and its dorsal plates modelled after those found on a Stegosaurus.

Phil Currie studying a Tyrannosaurus skull and its large teeth used for crushing bone.

Courtesy of Atlantic Productions

Novelist Michael Crichton, the best-selling author of The Andromeda Strain and Congo, wrote a thriller in 1990 about what would happen if dinosaur DNA that had been sucked out by mosquitoes and preserved for millions of years in amber was used to create dinosaurs that could live in the modern day. Using an entertaining blend of science and fiction, Jurassic Park showed that every dinosaur for itself meant that humans were in deep trouble. The mega bestseller was made into a film in 1993 by Steven Spielberg, the most commercially successful filmmaker of all time with hits such as Jaws and E.T.: The Extra-Terrestrial.

Jurassic Park created a worldwide dinosaur mania. The film became the highest grossing movie ever at the time, earning more than $1.2 billion worldwide at the box office. The film’s 1997 sequel, The Lost World: Jurassic Park, was the second highest grossing movie worldwide that year, and the movie-going public was terrorized yet again by the modern-day dinosaurs in 2001 with Jurassic Park III, another huge box-office hit. Universal Studios also built an elaborate Jurassic Park ride, complete with a 15-metre (50-foot) Tyrannosaurus rex, at its Hollywood theme park and a Jurassic Park River Adventure at its Orlando amusement park, which have attracted millions of visitors.

As accurate as parts of Jurassic Park were, such as promoting dinosaurs as the ancestors of birds, the filmmakers also took some artistic licence to up the ante. For starters, the novel’s and film’s premise is based on a real scientific improbability. The film also had some of its dinosaurs living in the wrong time period. Tyrannosaurus rex, nicknamed T. rex, and Velociraptor, known by its catchier nickname ‘Raptor’, were the featured dinosaurs in the movie, and yet both lived millions of years later in the Cretaceous period, rather than the earlier Jurassic period. And the message of the movie – that if you had a fast truck you could escape the dinosaurs because they were slow – appears not to be true.

The Jurassic Park phenomenon was a bellwether event that shined the spotlight on dinosaurs, and by extension on the work done by devoted palaeontologists who spend their lives trying to piece together how the ancient beasts lived and died more than 65 million years ago. Museums with dinosaur exhibits saw a 40 per cent spike in attendance in 1993, and there was little drop-off in the ensuing years.

Noted palaeontologist Phil Currie embraces popular culture as a way of generating public interest in dinosaurs. In fact, through a friend Currie was able to enlist Crichton to write the introduction to his academic Encyclopedia of Dinosaurs.

‘I love science, but I love science fiction, too,’ Currie says. ‘It was pretty uncanny what they did in a lot of ways, both Crichton originally and Spielberg subsequently. Crichton was very good at creating suspense and hooking you. I’m sure he had an awful lot of fun writing these books because he got to delve into something to the degree that very few people ever do except for the scientists or sociologists.’

Currie has been infatuated with dinosaurs since he was six years old, and his obsession with these creatures remains to this day. He is one of the world’s most highly regarded palaeontologists, the Indiana Jones of the dinosaur trade. In fact, Currie even sounds like Harrison Ford, the actor who played Indiana Jones. Tall and slender with tousled grey hair, Currie lives like a man on a mission to find out more about the beasts he loves. He is so afraid of his focus being diverted that he doesn’t own a mobile phone or accept voicemail messages. He saves times by walking up – and down – the stairs two at a time, and to ensure not a moment is wasted, every appointment must be run through his wife and assistant, Eva Koppelhus, a palaeontologist in her own right.

Currie has impeccable credentials: he has served as a museum curator and one of the founders of the Royal Tyrrell Museum, one of the premier dinosaur museums in the world, and he is a distinguished professor holding a Canada Research Chair at the University of Alberta in Edmonton, a city literally built on dinosaur remains. Between 1986 and 1990 he served as co-director of the Canada–China Dinosaur Project, the first palaeontological partnering (in the Gobi Desert) between China and the West since the Central Asiatic Expeditions of the 1920s. He has helped describe some of the first feathered dinosaurs, named many carnivorous dinosaurs and found some of the first dinosaur eggs in North America. He is one of the primary editors of the influential Encyclopedia of Dinosaurs, and has written groundbreaking scientific papers and non-fiction books as well as a series of fictional children’s books on dinosaurs with his wife. He also teamed up with Microsoft’s Nathan Myhrvold to construct a computer model that showed that sauropods (‘lizard-footed’ large plant eaters) actually broke the sound barrier with their mighty tails as they swung them to scare off their enemies. But for all his stature in the palaeontology world, Currie keeps a practical, child-like approach to his trade, because to him, dinosaurs are ‘really, really cool’.

For the past 15 years, Currie has been on a physical and intellectual journey to piece together a jigsaw puzzle that could change the way we think about massive killer dinosaurs for ever. He believes that tyrannosaurids, the most fearsome family of carnivorous dinosaurs, were far more complex and more dangerous than we ever could have imagined.

‘Part of the problem is just that we always tend to lump dinosaurs together,’ Currie says. ‘We know dinosaurs existed for 150 million years and we think that they didn’t go through any changes. But Tyrannosaurus was the top predator of the very end of the age of dinosaurs. Those were the most highly adapted, large predators that existed during the entire age. And I think they were by far the most dangerous animals.’

The tryannosaurid family had a dozen species. They were part of the Coelurosauria clan, which contained all bipedal, theropod (‘beast-footed’) dinosaurs. Most were small meat-eaters, such as oviraptorids, ornithomimids and dromaeosaurids (including Velociraptor), and some dated back to the Jurassic period. Tyrannosaurids came from animals similar to Velociraptor and were relatively late in the timeline of dinosaur existence.

Currie has focused on a member of the tyrannosaurids that hasn’t drawn much attention: Tarbosaurus, which lived in the Gobi Desert, was a cousin of the fierce Tyrannosaurus rex, an inhabitant of North America. Imagine a beast 12 metres (40 feet) long, 3–4 metres (10–13 feet) tall and weighing in at 5–6 tonnes. Its massive skull was packed with 64 giant, serrated, bone-crushing teeth, and it also had what appears to be one of the biggest brains of any of the large meat-eating dinosaurs. That was Tarbosaurus.

‘Tyrannosaurs were the most highly adapted large predators and … by far the most dangerous animals.’

‘Tarbosaurus is probably best known because of its cousin, Tyrannosaurus rex, and for a long time after Tarbosaurus was discovered, it was actually called Tyrannosaurus because it looks very similar in most ways,’ Currie explains, referring to the dinosaurs in the present tense as he often does. ‘So we have a large animal that kind of looks like an over-grown chicken on hormones. If this thing is standing on its two hind legs, basically it can’t use its forelimbs at all for locomotion. In the case of Tyrannosaurus, they become very reduced and small although they still have fairly big claws and muscles. Tarbosaurus is even crazier in having even smaller arms.’

Tarbosaurus was discovered in 1948 and was originally named Tyrannosaurus bataar (and later Tarbosaurus bataar) by a Russian scientist named Evgeny Maleev in 1953. A few scientists still consider these the same animals, but Currie points out that there are fundamental differences. ‘They are animals that look very much the same because they are mostly the same size, but they are not the same,’ he says. ‘The easiest difference to pick up on is the arms of the animals. Tyrannosaurus has really short arms, but Tarbosaurus has even more ridiculously short arms.’

Next to Tyrannosaurus rex, Tarbosaurus is the largest tyrannosaur that existed, which makes it one of the top three or four giant predators ever in the world. Tarbosaurus was an animal with a very large skull, and this skull was very powerfully muscled. Over time, the back of the skull expanded laterally so that it could build up muscle mass to allow it to close its massive jaws in a powerful bite. Its teeth were the size of bananas, and the reason those teeth became so thick is so they could function as bone crushers, rather than steak knives. The teeth were able to slice through flesh because the jaws had so much power in them and because they were sharp tipped. At the same time, the thickness allowed them to break bones, which they swallowed with the flesh. This was a dinosaur that was very well adapted for eating other animals.

Tarbosaurus had very powerfully built hind legs that were relatively long. ‘When you look at not just the length of the legs but the proportions of the legs, tarbosaurs are built more like ostriches than human beings,’ Currie says. ‘This meant that they were capable of reaching very high speeds for their size.’

Tarbosaurs had also adapted their bodies so that they weren’t quite as heavy as one would expect them to be. Rather than resembling a small meat-eating dinosaur that had been blown up to a larger size, its body proportions had changed considerably to prevent it from having too much weight to haul around. That excess weight would have been a problem because these animals ran on their hind legs, making them like seesaws.

‘This was a really nasty animal, and in spite of its size and that it looked so primitive to us, this was also a dinosaur that was very, very sophisticated in a lot of ways. If you look at the brain size of this animal, it’s not as big as a human being, but if you compare the brain size of a Tarbosaurus to the brain sizes of any of the animals it was chasing down, then it had a pretty respectable brain size. Even compared to modern lizards and crocodilians, turtles and things like that, this dinosaur had a fairly big brain. The bottom line was that it was a pretty sophisticated dinosaur and a very efficient killing machine.’

A Tyrannosaurus looked like an over-grown chicken on hormones.

Friedrich Saurer/Science Photo Library

In 2009, Currie went on a voyage of discovery, revisiting places and ideas from his 30 years in palaeontology to reveal one of the last major unknowns in dinosaur biology. He was accompanied to dinosaur sites and high-tech labs by several internationally renowned scientists: Dave Eberth, a Canadian sedimentologist and habitat specialist; Yoshi Kobayashi, an associate professor at Hokkaido University who is Japan’s top expert in carnivorous dinosaurs; Yuong-Nam Lee, a Korean herbivorous dinosaurs specialist; Louis Jacobs, an American college professor and renown vertebrae fossil expert; and Larry Witmer, an American scientist and professor engaged in cutting-edge research into dinosaur brains.

In addition to debating and fleshing out his theories with the experts, Currie wants his findings to be presented to the widest possible audience. He seeks to dispel the notion that studying dinosaurs is conducted by scientists holed up in windowless labs with microscopes examining ancient bones that have little relevance. Instead, he hopes to show that dinosaurs were not just fossilized stones but living, breathing creatures that may have quite a bit to say about the history of our planet.

chapter 1
the world of dinosaurs

What exactly is a dinosaur? Dinosaurs were a diverse group of animals that first appeared some 225 million years ago and lived on all seven continents, with more than 1000 species having been identified. Though they had a slight resemblance to lizards, dinosaurs distinguished themselves from other animals on the planet at the time because many of them could walk on two legs. The primary characteristics that scientists use to classify these terrestrial animals were an upper leg bone with a ball and socket joint at the hip, a streamlined lower leg bone and an ankle that functioned as part of the lower leg bone.

Dinosaurs roamed and dominated the planet for more than 160 million years during the Mesozoic era, making them one of the most successful animal types ever.

The Mesozoic era is divided into three periods: the Triassic (225 million to 213 million years ago), the Jurassic (213 million to 144 million years ago) and the Cretaceous (144 million to 65 million years ago). Dinosaurs were at their most diverse and evolved in the Late Cretaceous period, the time when tyrannosaurids ruled the Northern Hemisphere, and it is this period that is the primary focus of many palaeontologists.

At the end of the Cretaceous, dinosaurs had been around for some 160 million years and were at the peak of diversity. The different groups were highly specialized in many ways. They lived everywhere on the planet, all the way from the Arctic to the Antarctic at that time, in environments that were quite diverse. In North America, there were coastal regions and areas that were closer to the mountains that were rising at the time, and there were also dry areas and deserts in some places. Each one of those habitats was home to different groups of dinosaurs because each dinosaur species was adapted for specific climates and environments.

Size is often the first thing people think of when dinosaurs are mentioned. Though the dinosaurs portrayed in popular culture are usually shown to be huge, the fact is that most dinosaurs were the size of humans or even smaller. Because the fossil record is incomplete, scientists sometimes use educated guesswork to estimate the absolute size of the biggest and smallest dinosaurs.

The longest dinosaur is believed to have been Seismosaurus, which lived during the Late Jurassic period. Seismosaurus was a sauropod, or plant-eater, with a long neck and swooping tail that from head to tail measured between 35 and 40 metres (115–135 feet) long. The length is estimated because only part of the best Seismosaurus skeleton was recovered from its northern New Mexico site and the specimen is still being prepared. Despite Seismosaurus’ impressive length, it weighed less than 30 tonnes – heavy but nowhere near the heaviest sauropods (found in Argentina) that are believed to have weighed as much as 100 tonnes. (The largest carnivores were Tyrannosaurus rex and Giganotosaurus carolini, both of which lived in the Cretaceous period, the former in North America and the latter in South America. They each measured about 13.5 metres (45 feet) long and weighed about 6 tonnes.) By comparison, a blue whale can grow to 30 metres (100 feet) in length and weigh a shocking 180 tonnes.

On the opposite end of the scale, a herbivore find that was aptly named Mussaurus, or ‘mouse lizard’, would have fit in the palm of an adult’s hand. Compsognathus, or ‘elegant’ dinosaur, one of the smallest adult carnivores, was the size of a large chicken and weighed approximately 3 kilos (7 pounds). Microraptor was an even smaller carnivore find in China from the Early Cretaceous.

Dinosaurs fall into two basic categories: herbivores (plant-eaters) and carnivores (meat-eaters). The plant-eaters greatly outnumbered the meat-eaters. Some of the best-known herbivores were all quadrupeds, including sauropods, anklyosaurs, stegosaurs, hadrosaurs and horned dinosaurs like Centrosaurus. Sauropods had long necks, tiny heads and massive bodies. Ankylosaurs were very wide-bodied with massive plates of bone covering them like armour. Hadrosaurs are commonly called duckbilled dinosaurs because their mouth looked very much like a modern duck’s bill. Stegosaurus was distinguished by rows of bones along its back that developed into plates. Centrosaurus is one of the most common ceratopsians, or horned dinosaurs, which can be identified by their unique skull features not found elsewhere in the animal kingdom. On the tip of the upper jaw is a rostral bone, which forms what looks like a parrot’s beak.

‘Fossils – objects that have gone through permineralization.’

The best-known bipedal carnivores are Allosaurus, Velociraptor, Albertosaurus and Tyrannosaurus. Allosaurus, or ‘different lizard’, was a large predator in the Jurassic period with extremely sharp teeth and it often measured over 8.5 metres (28 feet) long. Velociraptor and its closest relatives (the ‘Raptors’) were feathered dinosaurs, most of which only grew to the size of large dogs. Each had four claws on each foot, one of which was adapted as a can opener and used to disembowel prey. Albertosaurus is noteworthy for its two-fingered hands and massive head containing dozens of large, sharp teeth. Despite being a top predator in its area and weighing more than 2 tonnes, Albertosaurus didn’t come close to measuring up to the monstrous Tyrannosaurus.

Dinosaurs were given their names by the scientists who described them in scientific papers. Because all languages are different, the names are then translated into Latin or ancient Greek, the common languages of scientists the world over, despite being ‘dead’ tongues. There is no set way to name a dinosaur. Some of the names focus on a characteristic of the dinosaur and others on how it might have lived. For example Tyrannosaurus rex means ‘tyrant lizard king’, while Tarbosaurus translates as ‘terrifying lizard’. Other names refer to the locations where they were discovered; Albertosaurus was first found in Alberta, Canada. Dinosaurs have also been named as tributes to people, such as Othnielia, which was named in honour of palaeontologist Othniel C. Marsh.

What scientists know about dinosaurs has come from fossils – objects that have gone through permineralization, the process by which minerals are deposited in the pores of bones and turn to stone. Fossilization is a very fickle process. The sediments and groundwater must be right for preservation. There must be an accumulation of sediments and no rain and wind washing them away over the millions of years. In the mountains, erosion prevents long-term accumulation of fossils, because if bones were buried, it wouldn’t be for very long because the sediments would be washed out of the mountains into the low lands.

Fossil is derived from the Latin word meaning ‘dug up’, and this is truly the case for dinosaur fossils. Most evidence of dinosaurs comes from original bones infilled with minerals, rather than from imprints of them frozen in time or bone that has been replaced by stone. In some cases, dinosaur bones were encased in ironstone nodules after they were buried, and this protected the bones from water-carrying minerals in solution so that to this day the fossils look just like modern animal bones. Others lines of evidence come from footprints, eggs and even skins that have been fossilized and preserved in stone. Scientists are able to date many dinosaur fossils from the rocks they are found in, and this has enabled them to establish an accurate timeline for dinosaurs despite the fact that they lived millions and millions of years ago.

The dinosaur timeline was established largely through a process called radiometric dating of fossils. This involves comparing radioactive isotopes to the decayed material found in the same rocks or the surrounding layers of rocks. In North America, significant volcanic activity created ash beds that contain radioactive material. In this case, when scientists find a layer of ash, then a layer of fossils, then another layer of ash, they know that the fossils between those two ash beds are bracketed by the two dates, the lower bed providing the older date and the higher bed the younger. They can then compare those fossils to similar ones found in Europe and conclude the Europeans ones are the same age. The radiometric dating techniques used provide dates of plus or minus 10 per cent accuracy, so 90 million years would have left a 9-million-year margin of error. But more sophisticated testing now provides dates to plus or minus a couple of hundred thousand years. In human age, that’s not very close, but in terms of dinosaurs, it is.

Dinosaur footprints. Four trackways of dinosaurs moving to the upper left, and at least one other dinosaur coming from the upper right and one from the lower left.

James Steinberg/Science Photo Library

Fossilized dinosaur footprints have been helpful to palaeontologists in determining what kinds of dinosaurs lived in certain areas. Though they can only rarely identify the species of the animal through footprints, palaeontologists can tell the general type of dinosaur that made the prints. Footprints are particularly revealing in situations where there are consecutive footprints that continue in one direction. These are called trackways, and they have enabled palaeontologists to draw both physical and behavioural conclusions about dinosaurs. Trackways reveal that most dinosaurs walked upright and did not drag their tails. They also show evidence of which dinosaurs were living together. And in certain situations, the stride lengths in the trackways can be measured and used to estimate speed. Without fossilization, this would not be possible.

There are long-simmering controversies among palaeontologists about the details of how dinosaurs were born, how they lived and how they died. Although there is no exact way to determine how long each species of dinosaur lived, scientists estimate that most species lasted between 2 and 5 million years. Their life spans varied by species and size. Some of the larger dinosaurs, such as Allosaurus, are believed to have lived for around 50 or 60 years, while smaller ones like Compsognathus may have lived for only 5 to 10 years. Velociraptor is estimated to have lived for about 20 years, and Tyrannosaurus and Tarbosaurus about 30.

One of the most hotly debated questions was whether or not dinosaurs were warm-blooded. The advances in that area changed dinosaur science and offered a prelude to more complex theories.

In the late 1960s, palaeontologist John H. Ostrom led the way in arguing that dinosaurs were warm-blooded. Ostrom was a professor at Yale University and in his later years served as Curator Emeritus of Vertebrate Paleontology at the Peabody Museum of Natural History. This was a radical idea at that time. Ostrom’s 1964 discovery and subsequent study of Deinonychus led him to conclude that the animal’s horizontal posture and sleek body, combined with the sickle-shaped claw on each foot, dubbed the ‘terrible claw’, offered convincing evidence that it was an active predator with a high metabolism. He could also see that it looked very much like Archaeopteryx, the first bird. He had also found multiple specimens of Deinonychus in the same quarry in Montana. This caused him to assert that small, meat-eating dinosaurs were behaviourally complex and may have lived in packs. Ostrom’s student, Robert Bakker, further argued these characteristics meant that dinosaurs were, in fact, warm-blooded.

Velociraptor.

Joe Tucciarone/Science Photo Library

These revolutionary theories changed the way dinosaurs were shown and started what Bakker later dubbed the ‘dinosaur renaissance’, a period of study that eventually would double our recorded knowledge of dinosaurs. ‘All of those ideas were coming out of that one find,’ Phil Currie says.

There are now many lines of argument that dinosaurs were warm-blooded. One is bone histology, or microscopic anatomy. ‘The structure of dinosaur bones is very much like the structure of mammal or bird bones, and it’s quite different than what we see in reptiles,’ Currie says. However, he cautions that, by itself, bone histology doesn’t prove warm-bloodedness, because it may just indicate very active growth. ‘Then you argue you don’t have active growth unless you can sustain it, and you don’t sustain it unless you have warm-bloodedness,’ he adds.