Why Did T-Rex Have Such Short Arms? Scientific Study of ‘Sue’ Could Determine the Answer

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Tony Maples Photography


A viral video showing the many theories that are being developed and researched on the nature of, or even the benefit of, a Tyrannosaurus Rex (T-Rex) having the short, stubby arms we now know them to have, has been posted by Minute Earth on their YouTube account, and it’s causing pause for thought. Minute Earth’s channel is dedicated to short, animated videos teaching the answers to, or asking valuable questions about, scientific items of curiosity here on Earth. Narrated by a team member, their animations fit the topics, and most likely keep a younger generation enthused, while at the same time, discusses subject matter that adults can relate to and (speaking from experience), often wonder about.

The video goes on to show viewers possible causes and natural effects that could result from the shortness of a T-Rex’s upper appendages, including posing the question as to whether there was, in fact, an evolutionary advantage to be had. They also touch on the opposite theory – that as opposed to having short arms as an advantage, they had them because large ones would have been a disadvantage. It also discusses the concept that the length of the arms neither hurt nor helped the animal, and that simply by quirky “luck of the draw”, that’s what they were given. It makes you wonder if the Texas Hill Country T-Rexes got married simply for the benefit of having another to scratch their itches! Those poor, miserable, killing machines…

The video goes on to show how modern day traits are discerned in other animals and humans to be of either an evolutionary development or weird, dumb luck. It also explains that scientists are presently studying the microscopic wear and tear on the arm bones of “Sue.” Sue is the name that was given to the largest, most extensively and best-preserved T-Rex skeletal specimen ever discovered. She was over 90 percent recovered in bulk in August of 1990, by a paleontologist named Sue Hendrickson (hence the name), and she now resides as a permanent fixture at the Field Museum of Natural History in Chicago, Illinois. The study of her arm bones could help scientists determine whether the short arms on such a gigantic meat-eater were designed to be useful, useless, or a purely random trait. Either way, how much do you want to bet there was no need for a Texas anti-bullying law back then? It would be more like a T-Rex anti-bullying law… “you bully, I bite. End of story.”