Imagine yourself living back in the age of the dinosaurs. Enormous beasts are roaming over miles and miles of terrain. You’re walking along a small path when you notice a ferocious Tyrannosaurus rex behind you. Should you run for your life? In the movie Jurassic Park, the scientist is confronted with a similar situation, his jeep won’t start and a giant T.rex is chasing after him. Jurassic Park is one of many movies that portray the T.rex as a dangerous predator constantly seeking prey.  But how was it possible for a creature weighing close to 17,000 pounds to live a predator lifestyle? The answer to that question lies in the speed of the T.rex, the production of the environment in which it lived, and its anatomy.

A 2003 study by Graeme D. Ruxton and David C. Houston of the University of Glasgow has provided evidence that disproves the commonly held belief that T.rex was a fast dinosaur. The researchers used two models to study this dinosaur’s potential speed, one based on a reptile’s metabolism and one based on a mammal’s metabolism. If one assumes that T.rex was a reptile, then it could have sustained a speed equal to 10% of its maximum speed over long distances. Because speed is dependent on weight, it is believed that the T.rex could have traveled at a maximum speed of 9.4 miles per hour. This implies that the sustained speed of T.rex was less than 1 mile per hour. If this is true, even a human could have outrun a T.rex considering that many people can run a mile in five to ten minutes.

However, there is some evidence that the metabolism of T.rex may have been more similar to a mammal’s than a reptile’s. One factor that led to this assumption was the fact that T.rex stood on its hind legs. If T.rex was similar to a mammal’s, then it could have sustained a speed equal to 50% of its maximum speed over long distances. But even then, its maximum speed would have only been 4.7 miles per hour. It is still hard to believe that a T.rex could have kept up with a speeding car at such a low rate. It would have been very difficult for an enormous beast such as T.rex to live a predator lifestyle because of its lack of speed. In the case of the movie, the scientist should have been able to speed away safely without any danger of the T.rex following close behind him.

The environment in which T.rex lived also supports the notion that T.rex could not have been a predator but was instead a scavenger. Scientists have found evidence to show the possibility that T.rex was a scavenger, meaning that it lived off of the food it found, mainly carrion, or flesh from dead animals. But, was there enough carrion to sustain these massive animals? It all depends on the production of the ecosystem in which this animal lived. An ecosystem is a localized group of organisms together with the environment that they inhabit and depend on. Ruxton and Houston compare the ecosystem in which the T.rex lived to the Serengeti national park in East Africa, which is highly productive and efficient. If such a comparison is indeed accurate, then the ecosystem in which the T.rex lived could have provided more than enough carrion or animal flesh for this creature to stay alive.

Many factors besides the high productivity of the ecosystem in which it lived could have made this possible. For example, evidence from fossils has shown that the T.rex was probably able to detect carcasses up to 330 meters away. The reasoning it could do so was because of its greatly enlarged nostrils suggesting that this creature had a keen sense of smell. Its nostrils were bigger than that of any animal alive today, even lions, which can sense flesh from long distances. However, the T.rex could only detect these carcasses one day after the animal had died because when the carcass begins to rot, the odor is much stronger and a lot easier to detect. Its ability to stand on its hind legs and its great stature enabled T.rex to tower above other dinosaurs and easily locate any dead animals in its path. Hence, the T.rex was able to maintain a scavenging lifestyle because of visual and olfactory pathways that helped the dinosaur locate its food.

The movie Jurassic Park does not accurately portray the behavior or lifestyle that a Tyrannosaurus rex once lived. A T.rex would have never been able to keep up with a speeding car and would have never gone after a human in the first place. Scientists have found evidence that disproves the common notion that T.rex was a predator. So the next time you go to see a movie, be careful not to believe everything you see. It’s not always true.

Bibliography

 

Ruxton, Graeme D. and Houston, David C. 2003 Was Tyrannosaurus rex a scavenger?

Proc. R. Soc. London.  270, 731-733.