|...chicken? I guess these tasty things are more accurate than we thought!|
Dinosaurs and birds don't look anything alike! How can they possibly be the same kind of animal?
Sure many dinosaurs were absolutely HUGE and most birds tend to be tiny and light with feathers. So...
|This seventy-foot long Brontosaurus...|
|...is related to this tiny Hummingbird???|
Valid question. Its true the sauropod is big and the hummingbird is tiny. Also the two animals seem to lead very different lifestyles one being a lumbering land animal and the other a flitting flier. But nature works in interesting ways. Many times two animals may not appear to be related at all but if you check out their DNA or even just their fundamental physical characteristics that may not be obvious at first glance it can be discovered that they are, in fact, closely related. I could just as easily make the same argument that...
|...this huge Blue Whale has nothing in common with...|
|...this tiny, flying bat.|
But birds are the only animals that have feathers! That should make them unique enough not to be grouped with dinosaurs.
This is just false. Over the years paleontologists have been discovering many dinosaur fossils that have feathers or show direct evidence of feathers that are most definitely not birds.
Velociraptor, for example, is a dinosaur that lived during the Cretaceous, a time when true birds had already evolved. Interestingly enough, Velociraptor had these little bumps on its wings that match exactly to bumps found on modern bird wings where the feathers attach to the body. These structures are called quill knobs.
|Velociraptor arm bone with quill knobs.|
|Yutyrannus bones clearly showing feathers.|
Don't misinterpret me here. I am saying that birds are a kind of dinosaur. Not all dinosaurs were necessarily birds though. Just like a dog is a mammal yet not all mammals are necessarily dogs.
Well what if feathers evolved multiple times and it's just a coincidence that both birds and dinosaurs had them? Its not like birds have anything else in common with dinosaurs!
Well, hypothetical nonbeliever, birds actually have a LOT of features that are common only to them and other dinosaurs. The most obvious of these is something that you can see any bird doing at any time; walking or standing on two legs. Birds are obligate bipeds. This means that they walk on two legs and two legs only. Birds and certain dinosaurs are the only known animals in history to be obligate bipeds. Yes, many animals, including us humans, walk on two legs BUT we can also drop down to all fours if we wanted to.
Birds and some dinosaurs, on the other hand, have front limbs that physically can't be used for movement on the ground.
|This tyrannosaurid, Lythronax, couldn't use its front limbs for walking even if it tried.|
All these examples so far just show evidence from extinct dinosaurs. Do modern birds have any features that are like dinosaurs?
Of course! Its common knowledge that all birds have feathers. But did you know that all birds also have scales like a reptile...or a dinosaur? Check out the foot of any bird.
|Bald Eagle...with scales.|
Check out this one! It even has the exact same shape as some (other) dinosaur feet!
|Rhea...with scales as well as a very distinct three forward facing toe design identical to...|
|...the foot of this Tyrannosaurus rex!|
We looked at feet now lets check out the hand claws on some birds.
Wait a minute! Birds don't have hand claws! They have wings!
Actually, some have both. Take a look at this modern bird called a Hoatzin.
So there you have it! I realized that just saying "birds are dinosaurs" isn't really enough so this is my blog post with my arsenal of science to back the statement up. There is also a lot of other evidence out there but I would be writing a novel of a post if I tried to include it all (hips...leg joints...the list goes on) If you still have questions about this, or any other dinosaur topic for that matter, you are always more than welcome to post or message us on our facebook page where I can answer you.
American Museum of Natural History. "Velociraptor had feathers." ScienceDaily 2007-09-20. Accessed 2012-07-20.
Hutchinson, J.R. (2006). "The evolution of locomotion in archosaurs". Comptes Rendus Palevol 5 (3–4): 519–530
Xu, X.; Wang, K.; Zhang, K.; Ma, Q.; Xing, L.; Sullivan, C.; Hu, D.; Cheng, S. et al. (2012). "A gigantic feathered dinosaur from the Lower Cretaceous of China" Nature 484: 92–95.