BIRDS ARE THEROPOD DINOSAURS
In recent years, scientists studying dinosaurs and birds have
come to a remarkable conclusion. Not all dinosaurs vanished in the
great extinction event that marked the end of the Cretaceous period
and the beginning of the Tertiary period 65 million years ago. Rather,
a number of small, arboreal dinosaurs of the theropod
and radiated into new forms. Their descendants are still dinosaurs,
and are still with us
today. We call them birds.
From the beginning of dinosaur studies in the 19th century, the
affinities between birds and dinosaurs have been well known. For most of that
time, birds have been considered descended from or related to dinosaurs.
Since about 1995, however, new discoveries have made the conclusion
overwhelming, at least to
most scientists, that the relationship is more direct than had been realized.
Birds aren't just descended from dinosaurs - they ARE dinosaurs.
Because of this realization, we registered our aviary as the
Theropod Aviary in honor of the continued existence of these animals,
so different from humans, that have fascinated so many of us for so
Here are some references which can provide more information if you
find this topic as interesting as we do. We include a brief quotation
from each source.
"Birds and dinosaurs share over 100 similarities in their bodies, including
hollow bones; clawed, three-toed feet; unique ankle and wrist joints;
and feathers. Based on the evidence, we can say that birds are not only
the living descendants of dinosaurs - birds are dinosaurs. We can think of
all modern birds as living, breathing, feathered dinosaurs."
Feathered Dinosaurs of China
Gregory Wenzel, Charlesbridge, 2004, p. 31
Thin, children's book, well worth having for the wonderful color illustrations.
"We now tell our students that birds are card-carrying avialian,
maniraptoran, coelurosaurian, tetanurine, theropod, saurischian dinosaurs,
and don't you forget it! Because in doing so, you would be denying them
their rightful claims to a proud and distinguished ancestry."
The Mistaken Extinction: Dinosaur Evolution and the Origin of Birds
Lowell Dingus, Timothy Rowe, W.H. Freeman and Co., 1997, p. 205
A more or less personal story by the authors of their discovery - and the
scientific community's discovery - of the facts about birds as dinosaurs. Also
discusses the true extinction of the dinosaurs. That is, the one going on now
which is largely caused by us.
"Now we must acknowledge that birds are a group of feathered theropod
dinosaurs that evolved the capacity of powered flight"
"Which Came First, the Feather or the Bird?", Richard O. Prum and Alan
H. Brush, "Scientific American" for March, 2003, Page
An excellent article on the evolution of feathers and the creatures
that use them, as well as on the development and growth of feathers on
those creatures during their lives.
"While dinosaurs, as we usually think of them, died out at the end of
the Cretaceous period, the class Dinosauria did not become extinct at
that time. It contains more than 9,000 species of living birds, and it
remains one of the most diverse groups of vertebrates alive today" p.
"Thanks to evidence that has come to light in recent times, we now
know that dinosaurs are, in fact, not extinct. The avian members of
the group survive in their highly successful descendants - the more
than 9,000 species of living birds." p 87
The Time-Life Guides Dinosaurs Christopher A.
Brochu, John Long, Colin McHenry, John D. Scanlon, Paul Willis,
Time-Life Books, 2000
If you can obtain only one of the works mentioned on this page, this
is the one to get. This is an excellent survey of all aspects of the
current state of knowlege about dinosaurs. Well written, well
illustrated and as up to date as a book can be. Includes a section on
individual dinosaurs, and a section on the most recent finds at the
time of writing.
"... we can now say that birds are theropods just as confidently as we
say that humans are mammals. Everything from lunch boxes to museum
exhibits will change to reflect this revelation."
"Feathers for T.REX?" by Christopher P. Sloan,
"National Geographic" for November, 1999, Page 102.
Excellent article on recent discoveries involving Chinese fossils.
Discusses Beipiaosaurus inexpectus, Sinonithosaurus millenii (sic),
Archaeoraptor lianingensis (Note: now known to be a fake!) and an unnamed oviraptoroasaur, and their place in the lineage of theropods. There are
excellent illustrations of these animals as reconstructed, as well as
photos of the fossils. Perhaps the most fascinating illustration
is of a down covered T.REX "chick" alongside a featherless adult.
"Let's cut to the chase: Birds are dinosaurs. As we shall see, this is
not quite so radical a statement as it sounds ...
"Claiming that birds are dinosaurs is no more radical than saying that
humans are mammals."
The Evolution and Extinction of the Dinosaurs David E. Fastovsky and
David B. Weishampel, Cambridge University Press, 1996, p. 293.
This is a college textbook, for use in Natural History courses. It is an
excellent overview of dinosaur studies. Interestingly, it features a
picture of Archaeopterix on the cover rather than more spectacular
"To be a dinosaur, then, according to current definition within the phylogenetic system, a given animal must be a member of the group descended from the most recent common ancestor of birds and Triceratops."
Article "Dinosauria: Definition" by Kevin Padian in
Encyclopedia of Dinosaurs, Edited by Philip J. Currie and
Padian, Academic Press, 1997, p. 178.
This is an excellent work, covering all aspects of dinosaurs as known
to about 1997. Unfortunately, it was published too soon to
include much of the material on the most recent Chinese discoveries, though it
does have information on Sinosauropteryx prima, the Chinese theropod
covered in what is thought to be proto-feathers. That dinosaur is
featured in the dust jacket illustration.
for the lineage leading from theropods to birds
shows that the clade labeled Aves (birds) consists of the ancestor of
Archaeopteryx and all other descendants of that ancestor. ... The
cladogram shows that birds are not only descended from dinosaurs, they
are dinosaurs (and reptiles) - just as humans are mammals, even though
people are as different from other mammals as birds are from other
"The Origin of Birds and Their Flight", Kevin Padian and Luis M.
Chiappe, "Scientific American" for February, 1998, Page 43.
An excellent article with good illustrations of some early birds/dinosaurs.
It has good, basic cladograms showing the evolution of Aves as a
sub-clade of Theropoda. A more complete cladogram is available in the
Encyclopedia of Dinosaurs, cited above.
"The evidence that birds descended from dinosaurs - indeed are
dinosaurs - has become conclusive for most paleontologists and
evolutionary biologists. ... A few scientists reject the dinosaur-bird
connection. They see the similarities as convergent evolution - the
development of like traits in separate species. To them dinosaurs and
birds share a common ancestor (which has yet to be discovered) but
evolved along separate paths. 'But they have no physical evidence,'
says paleontologist Hans-Dieter Sues of Toronto's Royal Ontario
Museum. 'Only dinosaurs are anatomically suited to be the precursors
"Dinosaurs Take Wing - The Origin of Birds", Jennifer Ackerman,
"National Geographic" for July, 1998, Page 74, and many sidebars to this article.
The quote above is from a two page sidebar called
"There's a Dinosaur in Your Backyard", page 96. This issue has many
excellent illustrations, including photos of fossils, charts, and
models of reconstructed dinosaurs.
"If the dinosaur-bird link was convincing before, it's now pretty
close to rock solid."
"Dinosaurs of a Feather", Michael D. Lemonick, "Time"
for July 6, 1998, Page 82.
Short but well written article, with a good illustration of