Did All Dinosaurs Have Feathers?

It seems that the line between dinosaurs and birds is getting more and more blurred with each passing day. While birds and dinosaurs have been known to be closely related for years, Dinosaurs have always been portrayed as lizard like and reptilian, a view popularized and sensationalized by the 1993 blockbuster Jurassic Park.  In fact, before the first dinosaur with feathers was discovered in China in 1996, the commonly held belief was that dinosaurs and birds had evolved convergently- adopting the same characteristics independently at around the same time- rather than having originated from a shared ancestor. 

However, in the last decade or so, this view has begun to change. Today, we know that birds and dinosaurs, rather than having evolved independently from one another, shared a common ancestor somewhere around 150 million years ago. Recent discoveries have shown that many theropods- a suborder of carnivores that includes the legendary T.rex– sported at least a feathery down, if not more elaborate displays of feathers meant to attract mates in much the same way as a peacock. Yet evidence of feathers outside of this suborder have been sparse, sparking questions in the scientific community over whether only carnivores or even merely theropods had feathers. 

T Rex fossil

By ScottRobertAnselmo (Own work) via Wikimedia Commons

Enter Kulindadromeus zabaikalicus, a 1-meter (5 ft) long feathery dinosaur found along the banks of the Olov river in Siberia. What makes this dinosaur spectacular is not its feathery nature, nor its (relatively small) size, but that it was a plant-eater- a herbivore- something until now unknown amongst feathered dinosaurs. This opens up a treasure trove of questions for scientists: how many other herbivores were feathered? Are feathered dinosaurs only small, like Kulindadromeus zabaikalicus, or could larger dinosaurs too have feathers? And, perhaps the most controversial and exciting question of all: is it possible that all dinosaurs could, in fact, have been feathered? 

Image courtesy of Andrey Atuchin

Image courtesy of Andrey Atuchin

There is something else exciting about Kulindadromeus zabaikalicus too that may serve as a stepping stone to answering the last question. zabaikalicus is an ornithischian- an order of  dinosaurs that split from saurischians, which includes meat eating dinosaurs and birds, around 200 million years ago— and, amongst ornithischians, sits relatively low on the evolutionary tree. It’s very possible, then, that the common ancestor for both meat eating dinosaurs, plant eating dinosaurs, and birds could have already had feathers, in doing so drastically changing our perception of how dinosaurs looked. Instead of the massive, terrifying lizards of Jurassic Park, dinosaurs may have looked more like today’s emus and ostriches. T. rex, in fact, could have resembled a giant, predatory chicken. 

More discoveries will have to be made, more of the fossil record uncovered, for any decision to be made for or against this claim, but for now, the possibility is tantalizing. As more and more signs point towards dinosaurs being more avian and less lizard-like, its possible that many of the assumptions we once held about dinosaurs- from their appearance to their behavior- may have to be torn down and built back up again. Only time will tell, but at the very least, its a fair guess that we can expect to see less scales and more plumage in the illustrations of our biology textbooks in the near future. 

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