SUMMARY: With or without feathers, let’s just admit that dinosaurs are still pretty cool.
Tyrannosaurus Rex – Scaled after all? (//Jurassic Park was right)
One of the big questions in society today, particularly amongst dinosaur nerds like me, is: Did they have feathers? We can’t help but wonder whether or not the beloved TV dinosaurs of our childhood were an accurate interpretation, or a pack of lies. So this post is going to examine the literature and figure out what’s what when it comes to our confused Dinosauria friends.
Theropods are a group of dinosaurs who are known to be bipedal, and groups of which are the ancestors of modern day birds. Many were carnivorous, and included such well-known dinosaurs as the Tyrannosaurus Rex and Spinosaurus. They lived during the Mesozoic period, from the Triassic to the Late Cretaceous. As the group with the closest links to birds, they are a key talking point in the debate. Other groups of dinosaurs, such as Sauropods, have no evidence linking them to feather-like structures.
In 2004, a study published in Nature described evidence of protofeathers found in primitive tyrannosaurids (ancestors of the T.Rex)1. Another study in 2012 displayed fossil images showing both juvenile and adult Ornithomimus specimens, covered in feathers 2. Feathers have also been found on several other species, including Caudipteryx, Beipiaosaurus and Compsognathus. So, with so many species of Theropods that are known to have feathers, the question seems to be answered. Dinosaurs had feathers, right?
Wrong. It’s not that simple. It turns out that feathers may have evolved over several events in history, not just from one point in time. It is, therefore, entirely possible that certain species had feathers, where as some species didn’t. It is also possible that while an ancestor may have been covered in feathers, through evolution they could have been de-selected and lost in favour of scales. It’s also entirely possible that some groups may have been partially covered in feathers.
Another study published in 2017 analysed skin fragments from Tyrannosaurus Rex, and other large tyrannosaurids, and confirmed that they indeed possessed scaly skin, with no evidence for any feather-like covering3. So, that’s it. Jurassic Park was right on this one (ha). Although it is worth mentioning that only fragments of skin have been discovered, so there may well still be feather coverings localised to specific areas. However the study goes on to provide theories for why they lost the feathers seen with their ancestors. As tyrannosaurids increased in size, they required better cooling mechanisms, which would include loss of insulating feathers from their skin. This may also have been caused by a shift towards a warmer climate.
So while the prevalence is unknown, it is clear this is not a black and white question. Some dinos did, some dinos didn’t. And while statistical analyses may help predict which species are likely to have feathery coverings, we can’t be sure until all of the fossil records are analysed. Which may take some time. So for now, just be happy in the knowledge that your T-rex toys are not too far from the truth, and as scientifically accurate works they are a perfectly acceptable collecting item for any adult.
- Xu, X., Norell, M., Kuang, X., Wang, X., Zhao, Q. and Jia, C. (2004). Basal tyrannosauroids from China and evidence for protofeathers in tyrannosauroids.Nature, 431(7009), pp.680-684.
- Zelenitsky, D., Therrien, F., Erickson, G., DeBuhr, C., Kobayashi, Y., Eberth, D. and Hadfield, F. (2012). Feathered Non-Avian Dinosaurs from North America Provide Insight into Wing Origins.Science, 338(6106), pp.510-514.
- Bell, P., Campione, N., Persons, W., Currie, P., Larson, P., Tanke, D. and Bakker, R. (2017). Tyrannosauroid integument reveals conflicting patterns of gigantism and feather evolution.Biology Letters, 13(6), p.20170092.