Why Did Some Dinosaurs Have Feathers?
Only a very few small dinosaurs were capable of flight in some form. So why did so many dinosaurs have feathers. Were there other purposes that feathers brought that could benefit dinosaurs enough that they evolved to become increasingly covered with feathers or is there another explanation. We take a look at that and more below.
Of the 1000 plus known species of dinosaur 77 are known to have feathers. As in modern birds these would have been used for reasons other than solely flight. Feathers would have offered benefits in displaying to mates, defense, waterproofing, camouflage, insulation as well as flight to dinosaurs possessing them.
Why dinosaurs have feathers, and which dinosaurs had feathers is an ongoing question with no definite answer yet. The benefits of feathers are well documents, and we list them below, however knowing if animals we can only see if fossils in rocks had them is more difficult.
Difficult doesn’t stop us though, and we give the answers below. Including the biggest feathered dinosaur ever found!
Why Did Dinosaurs have feathers.
As we highlight in the table further down this section, the evolutionary feathers offer at worst comparable benefits to fur, and really much more substantial ones and both these body covering offer more benefits than scales of warm, or partially warm animals.
Dinosaurs with feathers could have trapped small pockets of air, which while useful for flight was more likely to be used for insulation, while fur offers this too scales certainly don’t!
With dinosaurs being A form of warm blooded (endothermic) or a form of warm blooded (mesothermic) would look for any advantage to keep the heat they produced inside. feathers offered a great opportunity to do that.
Feathers are a great way to display to mates, and to competitors and it is likely ( though unknown at the moment) that some dinosaurs were actually brightly colored. They did have 200 million years to perfect that!
As we know feathers lead to flight, and although only one dinosaur is currently known to have been able to fly (archaeopteryx probably) it didn’t mean others couldn’t have got some lift from those early feathers and wings. It might be really useful if you are funning away from a hungry predator to be able to get yourself out of the way of its jaws.
Table 1: Usefulness of Feathers compared to hair as a body covering.
| Function | Ability of Hair or Fur | Abilities of Feathers |
| Waterproofing | Use of oils allows fur / hair to be waterproof or resistant, beavers, otters etc | Use of oils and feather density allows feathers to be waterproof |
| Flight | Only with skin or membranes in addition (and not the result of fur or hair) Bats, flying lemurs etc. | If evolved can provide flight capabilities |
| Display | Different colors and lengths | Size, shape, movement, display and rituals, position of feathers. |
| Shade | Protection of skin from the sun | Wings (and feathers) can be used to create shade to help vision. ( hersons do this in water) |
| Warmth | Fur provides insulation and can trap warm air. | Feathers provide insulation and can trap warm air |
| Defense | Ability to change and grow into horns and spikes | Able to be used as weapons’ but only as part of wings. |
| Camouflage | Abilities to blend into environment | Abilities to blend into environment. |
| Migration | Fur is easily to shed meaning it be grown when cold and shed when warmer. | Feathers are less easier to shed and regrow. Meaning migration was more likely |
Did Most Dinosaurs have Feathers?
The short answer is we don’t know if all dinosaurs had feathers, even if we ask the question did most dinosaurs have feathers the answer would depend who gave it to you. there are two schools of thought around dinosaurs and feathers. These thoughts are as follows:
Did all Dinosaurs Have Feathers:
Although today the only animals we know of with feathers are the birds they are actually a very useful body covering. Mammals have hair and are incredibly successful, but feathers are actually a more useful covering and not just for the obvious (and very useful) reason that they help you fly! We have included some of these uses when compared to hair below.
Some scientists think that feathers were much more common than we currently think in dinosaurs, and that most if not all dinosaurs had feathers of some description. they may not have been covered with them like microraptor or Yutyrannus but just like Elephants and Rhinos have some hair the larger unexpected dinosaurs like Brachiosaurus and triceratops may have had some feathers on their bodies here and there.
Currently about 77 species of dinosaur have been found to have been feathered in some form. this is about a total of over 1000 species found so far. So for us to describe that most dinosaurs had feathers would require significant more evidence.
Most Dinosaurs Did Not Have Feathers
However there is another group of scientists who think that actually most of the dinosaur species discovered so far did not have feathers and were the scaley terrors of the movies. this is what they have to say.
Analysis and research found that the first dinosaurs were likely not feathered, and that it wasnt from a distinct line that feathers evolved. That means there was not a Dinosaur zero that spawned all other feather dinosaurs basically.
It was thought for a few years that Kulindadromeus was kind of a missing link for the feather and dinosaur relationship as it had both scales and feathers and was over 150 million years old. This together with all the feathered dinosaurs currently being found with evidence of feathered has made people make the jump that all dinosaurs had feathers, however that evidence is not there ( yet)
If all dinosaurs, like the sauropods were covered in feathers then it would mean a huge rethink in how they heated themselves, as dinosaurs that large would overheat (basically cook!) if they also had insolation.
So when putting feathers on an argentinosaurus it’s important to think of more than just the appearance. It is astounding enough to think of an animal the size of a T-Rex being covered in feathers never mind scaling that up to an animal the size of a long neck dinosaur.
Which was the Biggest Feathered Dinosaur?
this is not as easy at grabbing a tape measure and just measuring a feathery fossil. it is thought that many dinosaurs actually had feathers including the Tyrannosaurs Rex. however thinking it and proving it are two different things.
the Largest provable feathered dinosaur discovered actually has a great deal of proof of those feathers. it was called Yutyrannus Huali which means “beautiful feathered tyrant.” Although maybe beautiful from far away it would still be a dinosaur to keep a distance from.
it was related to the tyrannosaurus rex, and, although smaller, was still upto 30 feet long and up to 3000 lbs in weight!. being related to Tyrannosaurus means it was certainly a carnivore, which makes its appearance a little disturbing.
The feathers were described by the Chinese scientist who discovered Yutyrannus
“as more like the fuzzy down of a modern baby chick than the stiff plumes of an adult bird.”
This means it looks like a large chick. A large chick with a huge mouth a teeth. Certainly not one to put on an easter card!
the discovery of Yutyrannus does bring up a few questions. It did not have feathers for flight it had them to keep warm. However large dinosaurs did not have much of a problem with body temperature as their size helped them maintain heat.
What was the previous largest Feathered Dinosaur?
Previous provable feathered dinosaurs were much, MUCH smaller where keeping warm would be more of a concern but not for larger animals.
The largest provable feathered dinosaur before yutyrannus was the Beipiaosaurus which was a type of Therizinosaurus ( and one reason it is thought the super large Therizinosaurus is thought to be a huge feathered dinosaur). The Beipiaosaurus was about 7-8 feet long and would have weighed about 200 lbs. it lived aroud 125 million years ago at the same time as the yutyrannus in what is now Asia.
Why did Yutyrannus have Feathers?
One thought which we will explore is that yutyrannus dated from the middle of the cretaceous period, about 125 million years ago, much earlier than the tyrannosaurus rex when the temperature on earth was considered much lower so maybe it needed that fluffy feathered coat more than its descendants millions of years later.
it could be the environment they lived in was colder than thought and a feather or fur covering would be needed. it may also be that our thoughts on what dinosaurs actually looked like or how they dealt with body heat may need looking at again as well.
What was the First Feathered Dinosaur?
The Anchiornis is currently the oldest provable feathered dinosaur that has been discovered. This creature lived during the late Jurassic period over 151 – 160 million years ago. this makes it older than the previous oldest the Archaeopteryx, which was found over 100 years ago.
The Anchiornis was similar in appearance to the Microraptor including two traditional wings, and then two. kinda. wings on its hind legs. Incredibly scietists were able to work out the colour of this dinsaour as well. ( it was black, browny red and grey)
it was a carnivore and was found with the remains of a 160 million year old lizard inside it as well. It really was an incredible fossil find. Not only did it provide evidence of feathered dinosaurs, we could tell the color and even what its diet was!
China Fossil formations are providing amazing evidence of feathered dinosaurs, with both the largest (see the Yutyrannus above) and the oldest evidence of these feathered dinosaurs being found.
It is a shame to see “old wing” Archaeopteryx being dethroned as the oldest known feathered dinosaur but with the rate that fossils are being found in China, it may not be long that Anchiornis is the oldest feathered dinosaur title holder.
Could Any Feathered Dinosaurs Fly?
We go into feathered dinosaurs in much more detail here on this article and on flying reptiles here which are often confused with Flying dinosaurs. However there were some dinosaurs that appeared to have developed flight of a sort, and this is likely to be added to as more fossils are found in the coming years.
At the moment the only dinosaur thought to be capable of powered flight, actually flapping its wings to fly, was the archaeopteryx its small size and wings have been found to be able to support powered flight. Using a synchrotron ( like a really powerful x-ray), scientists showed that like birds the archaeopteryx bones were hollow and therefore light. Although it was likely to be able to fly on its own power it as unlikely to be an elegant flyer, more like a pheasant than an eagle.
However there were other dinosaurs that could use those wings to at the very least glide. these dinosaurs include dinosaurs like the Microraptor and the sinornithosaurus. Which would have climbed trees and either glided down to the floor or from tree to tree.
Did Herbivore Dinosaurs Have Feathers?
As we mentioned above it is not thought that the larger dinosaurs like the long neck dinosaurs were covered with feathers like some of the theropods, just from their size it would have made them over heat. However some of the theropods that did have feathers would have been herbivores. Therizinosaurus is strongly thought to be feathered and was a herbivore.
Most feathered dinosaurs are of the type theropod, and most theropods were carnivores or omnivores.
Why Do Some Theropods not Have Feathers.
So famously the widest criticism of the Jurassic World and Jurassic Park Movies were the dinosaurs lack of feathers. It could be forgiven in the first as it was fairly new to be thinking of a furry Velociraptor or T-rex, but maybe not so much in the most recent movies ( explained away by genetics)
Dominion seems to meeting scientists half way and including some feathered dinosaurs in the new movie. The Pyroraptor and Therizinosaurus are featured quite heavily. However, the movie also features Allosaurus and carnotaurus which do not have feathers.
This, at our current knowledge, is entirely accurate! Some dinosaurs had feathers and others didn’t. Why was this so?
Well the first aspect to consider is that dinosaur fossils are incredibly hard to find and fragile and thats just the bones. Feathers are even more fragile and it is very very rare to have them fossilized. So it may be that we just havent found them on fossils liek allosaurus yet.
Another aspect is that these dinosaurs didn’t have feathers of course. Dinosaurs like Allosaurus are much older dinosaurs than Velociraptor, and T-Rex and it maybe that they went extinct before ( or were never going to) they evolved to have skin coverings. feathers or otherwise.
However the discovering of Yutyrannus put this theory into question as it was a 125 million year old relative of the T-rex and alive much closer to the Allosaurus than the T-rex.
Also carnotaurus did not have feathers that we know of, there are actual fossils of carnotaurus skin which show it to be scaly! However seeing as we don’t have all the skin it can’t be a complete jugement. It may have had remnants elsewhere.
One suggestion is that like young birds feathers may have been more important when smaller, and as the dinosaur grew it lost them apart from some areas like the back of the skull or their backs. it is also suggested as these large theropod dinosaurs evolved they also lost the need for feathers to keep insulated and lost them through evolution.
However that yutyrannus throws a 30ft wrench into that. Maybe it was just really Really cold where it lived!
Conclusion
Confused yet? you should be! The honest answer is that while we do know why dinosaurs had feathers, for the same reason all birds have them, warmth, display, flight, waterproofing, we can’t answer if all dinosaurs had them, if they had them and then lost them, or if only a few had them as specialized dinosaurs.
That’s the problem with dinosaurs and the delight. Even with as much as we know there is always more to learn, and we will keep you updated as we learn it !
Don’t forget to check out all our other dinosaur resources, fact sheets coloring and more on the big button below.
References
https://www.amnh.org/exhibitions/dinosaurs-among-us/feathers#:
https://www.britannica.com/story/did-dinosaurs-really-have-feathers
https://www.discovermagazine.com/planet-earth/did-all-dinosaurs-have-feathers
Hi, I am Roy Ford a General Studies and English Teacher who has taught all over the world. What started as a fossil collection became a great way to teach, motivate and inspire students of all ages and all over the world about dinosaurs and from that and children’s love of dinosaurs came the site dinosaur facts for kids, a resource for all ages.
