David Hone Talks Feathered Dinosaurs at Lakeside Arts

We actually know quite a lot about T-Rex as we have discovered 15-20 good skeletons, some of which are almost complete. There were around 30 different types of tyrannosaurs, ranging from 2 metres in length up to the T-Rex, which weighed up to 7 tonnes. They were around for 100 million years and the holotype (the specimen after which the species was named) for T-Rex can be seen in a museum in Pittsburgh. 

Before we get onto the feather question, Dave takes us into the mysterious past - 1993, to look at Jurassic Park. Back then, it represented the cutting edge of what we thought T-Rex looked and acted like. However, subsequently, we have discovered much more. In the film, it's described as having vision based on motion but in real life, T-Rex had eyeballs the size of tennis balls. These were actually the largest eyes of any creature to have ever lived on Earth. So, it could probably see very well. Due to it having forward facing eyes, it had true binocular vision so could judge depth and since birds, reptiles and amphibians are able to see in UV, there is s chance that T-Rex could too.

In Jurassic Park, the T-Rex is shown to be running at 30mph. However, for a creature weighing 7 tonnes to move that fast, 80% of it would have had to have been leg muscle. Juveniles would have been quicker than the adults but you don't have to be fast to be a hunter - you just need to be faster than or have more endurance than your prey. The second of these is where T-Rex excelled, due to its feet it was very efficient and so was very good at moving long distances. T-Rex was essentially a power walker and while it might not have reached 30mph, it could have gotten up to 15mph and kept going for a long time. 

T-Rex is always pictured as having two small arms, one on each side of its body but it actually had a wishbone!  First discovered in the 1980s, this meant that the arms would have been pulled in, right under the chest. Another popular image is the T-Rex righting against a Triceratops. However, in all of the David Attenborough documentaries, we see lions picking off the old, the young and the injured. This is because it represents the least danger to the hunter and if a carnivore is injured then it can't hunt and it will starve to death. Triceratops could grow to 10 tonnes so it's highly unlikely that a T-Rex would have risked fighting a fully grown Triceratops. 

Tyrannosaur skulls and teeth were stronger than other therapods and they had massive bite power. The teeth had a 6 inch crown and a circular cross-section and it could bite into solid bone with such force that indentations of teeth serration have been found. There are questions about whether T-Rex was a hunter or a scavenger but evidence exists that it was both. A skeleton was found where one of the arms had 100 teeth marks on it but there was nothing else on the rest of the body. It seems that it had become buried with just its arm free and a T-Rex had used its upper jaw in the way that a human would scrape the cream from a custard cream biscuit. However, there is also a specimen found where bone has healed around the tooth of a T-Rex, showing attempted predation. In terms of what they ate, there are 6 good records of T-Rex eating juvenile prey and also 3 instances of T-Rex cannibalism. From the perspective of researchers and how they know these things, the T-Rex was the apex predator at the time. The next largest carnivore was only a couple of feet long so when you find something with bite marks, it's going to be from a T-Rex. 

But what about those feathers? Until the late 1990s, Tyrannosaurs were seen as big, scaly dinosaurs but then a Delong specimen was found that clearly had feathers associated with its bones. These were more like hairs or the feathers on a bird chick rather than proper flying feathers and this was one of the small Tyrannosaurs. However, some specimens of Yutyrannus were discovered that were completely covered from nose to tail with feathers and these dinosaurs would have been 7 metres long.

A paper produced earlier this year argued that samples of T-Rex skin didn't have any feathers but did have scales. However, feathers don't preserve very well while scales preserve much better so just because there aren't any feathers doesn't mean that T-Rex didn't have them. Ancestors of T-Rex definitely had feathers and animals tend not to lose them once they have evolved feathers. So, T-Rex probably did have feathers but how many and what type, we don't know yet. 

The Dinosaurs of China exhibition continues until the 29th of October at Wollaton Hall and Lakeside Arts.

Dinosaurs of China website