I Think I’m Extinct

Jurassic Park and its consequences…

In 1993, Jurassic Park was released in theaters. At the time, it was the highest-grossing film in cinema history, and it revolutionized special effects in film. For the first time in history, people had a realistic view of what dinosaurs were like, and this sparked an interest in paleontology in the hearts and minds of millions, myself included. But what you may not know is the lasting effect Jurassic Park has had on the paleontology field — specifically through one man, Jack Horner.

The author of Jurassic Park, Michael Crichton, said that Horner was the inspiration for the character of Alan Grant. Horner was born and raised in Montana, one of the richest locations in the world for fossil hunting. In 1978, Horner was one of the lead paleontologists on a dig site in Montana that would later go on to be called Egg Mountain. There they made a huge discovery, finding a new species, Maiasaura peeblesorum (“good mother lizard”). This medium-sized Hadrosaur didn’t seem like a major discovery at first, but as they continued digging, they would discover something revolutionary: Maiasaura was found with egg shells, containing embryos, alongside its body! This was the first-ever concrete proof of dinosaurs being caring parents. The only dinosaur eggs discovered up until that point had been found in Mongolia in 1923. That site had produced one partial skeleton of a small theropod dinosaur, Oviraptor philoceratops (“egg thief”), sitting on top of a dozen eggs. It was originally assumed that the eggs were of another dinosaur, and that the Oviraptor had died while trying to raid the nest. New discoveries within the last 20 years actually show that the eggs were actually the Oviraptor’s. Not a nest-raider, but an adult actually sitting on its eggs, much like modern birds.

Reconstruction of a Maiasaura embryo

Horner would continue to raise his notoriety with more discoveries, including being on site for the excavation of the largest Tyrannosaurus rex ever found. He even had three dinosaurs named after him, one being a species of large Tyrannosaur, Daspletosaurus horneri. By the early ’90s, Horner was one of the most decorated paleontologists in the world. He secured the position of dinosaur expert on the set of Jurassic Park and worked hard with the special effects team to make the dinosaurs look as realistic as possible, notably making them act more like birds than like reptiles. The original design for the Velociraptors contained lizard features such as forked tongues like those of modern Komodo Dragons. Horner ripped those designs apart the first week he was on set. With the combination of Horner’s expertise and the advancements in CGI, legendary stop motion animator Phil Tippett was quoted on set as saying: “I think I’m extinct.” A line Spielberg liked so much he put it in the film. The success of the film made Horner the most famous paleontologist in the world, landing him plenty of media interviews and TV specials. This gave Horner the perfect platform to share some of his more radical theories which, in my opinion, have skewed not just the public perception of dinosaurs but have also misdirected the field of paleontology itself. There are a number of theories that Horner has put forth in the last 30 years that are nothing short of bizarre, two in particular which I’ll detail below, and another which I was shocked to discover as I was doomscrolling on Twitter.

The first relates to Tyrannosaurus rex itself. Jack has likely been on more T. rex excavations than any other person alive and clearly knows the animal very well. But starting in 1994, Horner started to question a very rudimentary characteristic of T. rex: Was it actually a predator? Just one year after the release of Jurassic Park, Horner published an article, “Steak Knives, Beady Eyes, and Tiny Little Arms (A Portrait of T. rex as a Scavenger),”¹ in which he argued that T. rex was actually not a predator but primarily a scavenger. In my opinion, the best piece of evidence — and an example Horner uses — is T. rex’s tooth design. Tyrannosaurs in general developed stronger and wider teeth than did previous carnivorous dinosaurs. Rather than having the thin, blade-like teeth of earlier Carnosaurs such as Allosaurus, Tyrannosaurs developed thicker teeth that gave them immense crushing power. Tyrannosaurs also developed stronger muscles attached to the back of their skulls, increasing their bite force. Some studies suggest that T. rex had a bite force of over 10,000 pounds per square inch (PSI), the strongest of any animal in Earth’s history. For comparison, the largest bite force today comes from the Saltwater Crocodile, at only 3,000 PSI.

One of the most useful tools in paleontology is comparing animals of the past to those alive today — not just to a prehistoric animal’s closest relatives, but also animals that share ecological niches (i.e., top predators tend to share features across time with other top predators, and so on). Dinosaurs share their ancestral tree with crocodiles in a family known as the Archosaurs. However, the other family that shares the dinosaurs’ ancestral tree are the Aves, the birds. Yet T. rex’s closest living relatives don’t occupy the same ecological niche that T. rex once did. So Horner offers the African Spotted Hyena as a comparison. While this seems absurd on its face, I agree with the example and think that it is Horner’s best argument. Spotted Hyenas are primarily scavengers and also have the strongest bite force of all African carnivores, at 1,200 PSI. They also have large muscles at the back of their skulls to increase their crushing power, and they also have wider teeth than other predators in their region, such as those of the big cats. Spotted Hyenas will eat everything on a carcass, including bones. Not only do they have strong enough jaws to break bone, but they have the stomach acid to digest it. Female Spotted Hyenas are also larger than males, something we know to be the case with T. rex as well. But let’s look at what makes a scavenger a scavenger and not just another predator.

Scavengers are key to any ecosystem, ensuring that no energy in the food web goes to waste. They remove carcasses from the ground, allowing for the continued growth of plants which feed the herbivores, which provide food for carnivores, and the cycle starts all over again. They also have adaptations that allow them to break down the toughest parts of the body that other carnivores can’t. This requires a large and specialized stomach with powerful acid to break down the strongest and foulest parts of the body. Generally, this specialized stomach is disproportionally larger compared to the rest of the body. This makes you slow, which makes it more difficult to catch prey. As such, scavengers throughout the world, from hyenas to wolverines to vultures, rely on the success of other carnivores to get their food. Hyenas are first on the scene of a lion kill, and while they won’t get the most nutritious parts of the body that the lions eat, all they have to do is wait. Lions will only eat around 40% of a carcass, the limit of what their jaws can crush and stomachs can breakdown. They are fast enough and strong enough to kill the prey, but they don’t have the stomachs and jaws required for eating all of it. The other 60% is for the scavengers. But what if a hyena wants the best parts of the body, the organs rich in vitamins and iron? He must either catch his own prey or bully another predator into leaving his. Hyenas are pack animals, living in clans of over 70 individuals in some cases. That’s a lot of strong jaws and teeth for a group of lions to deal with. Usually it takes four hyenas for every one lion for it to be a fair fight, and sometimes the hyenas win, even killing and eating the lions. The risk of having to fight and rely on other carnivores for food means that scavengers are never top predators in their environment. In some regions of Africa, hyenas rely on lion kills for over 65% of their diets. While being a scavenger gives you some advantages, in the end you are at the mercy of other animals in your environment.

Carnivores Don’t Tolerate Each Other

Mortal Enemies

Now all carnivores are scavengers to some extent. A free meal is always nice when you don’t take the risk, and lions will, if given the opportunity, occasionally steal kills from smaller predators like cheetahs and leopards. But they cannot sustain themselves off of just stealing kills, as they are too big and require too much energy, so they must hunt. I suspect that T. rex was no different. My biggest problem with Horner’s theory is that T. rex was the largest predator in his environment. Why would you evolve into the largest carnivore in your environment if you were just going to make a living off of stealing the kills of other predators? That would be a great waste of energy. If you don’t need a big body, then you don’t grow big. And while modern studies show us that Tyrannosaurs likely did live in family groups, I suspect that this group dynamic (given their immense size) would have better served them as pack hunters much like modern lions. Their prey were so large and so heavily armored that they needed to grow big and develop large teeth and powerful jaws just to get the job done. T. rex was feeding on armored herbivores like Ceratopsids and Ankylosaurs, giant Sauropods, and thick-skinned Hadrosaurs — many of these prey animals being larger than they were, again as we see with modern lions.

The second issue with this theory comes from direct fossil evidence of T. rex predation. Pete Larson is the curator of the Black Hills Institute just outside of Rapid City, South Dakota (a facility I was fortunate enough to visit a few years ago). Larson published an article in 2013 with the help of other scientists, “Physical evidence of predatory behavior in Tyrannosaurus rex,” in which they show signs of a T. rex attack on the skull of a Triceratops where the bone later healed. But the truly remarkable find was a skeleton of a large Hadrosaur, Edmontosaurus, in the Hell Creek Formation in South Dakota. This specimen not only survived an attack from a T. rex but also had a tooth fragment stuck in its vertebrae that the bone, over time, healed over. This is direct evidence of T. rex hunting prey; and in this case, the prey not only got away but lived long enough for the injury to heal afterwards.

Bite mark and subsequent healed injury

The final issue with this theory comes courtesy of remarkable new studies in brain scan technology, pioneered by Dr. Lawrence Witmer at Ohio University. Starting in the early 2010s, Dr. Witmer and his team began placing dinosaur skulls inside CT scanners to get a detailed look into the brain cavities of extinct animals. Using these scans and comparing them to T. rex’s closest modern relatives, we can see what parts of the brain are associated with certain functions. The results were revolutionary. T. rex, despite what Jurassic Park would tell you, had a large optic lobe, giving it exceptional vision on par with that of modern birds. The olfactory bulb, associated with the sense of smell, was also very large. This suggests that T. rex would first find his prey with the sense of smell and then use his excellent vision to find and chase his prey. While all scavengers have a very good sense of smell, they do not necessarily have excellent vision, because they don’t need it. You don’t need to keep your eyes on a target that is already dead.

Breakdown of T. rex’s brain

All of this evidence clearly points to the fact that T. rex, while it likely stole kills from its competition, was primarily an active predator. While Horner has stepped away from his theory over the years, he still makes some allusions to it in his work — whether as a meme or serious scientific study is anyone’s guess. In a series of NFTs Horner was developing in 2022, he gave T. rex the design he described in his original article: that if T. rex was a scavenger, then it would have likely looked very ugly, like a modern vulture, with a featherless yet brightly colored face in order to intimidate other animals. While proving what color dinosaurs were is next to impossible, I’m gonna go out on a limb here and assert that this design is highly unlikely…