My poor little girl lost her parakeet to our border collie. Then she lost another one to the cat. The next one flew out the open door. And the last one was killed by the cat too, but this time while trapped inside a closed cage! She was very upset that all her birds were dead. And any future keets would inevitably meet the same fate.
"Well Dear", I said, "maybe you just need a bigger bird!". But I didn't expect her to get the 2nd largest bird on Earth!
It was cute enough
as a tiny chick.
But it grew
at an average of 2 inches per week every week
for several months!
And soon it was
almost too big to conceal behind the six foot high fence in our back yard!
OK so I'm checking out our new emu chick and I discover something I didn't even know they had...wings. And not normal wings to be sure. In fact they're not really wings at all, but tiny vestigial arms, each with a single visible finger and on that finger is a claw!
Now there are a couple of reasons why that was surprising to find. One is that I was taught that there was only one bird in all the world that had claws in its wing. The hoatzin of South America has claws in its youth, which disapear as it matures. But that was supposed to be it. And emus aren't even closely related to hoatzins.
I read an undergraduate study of the emu that gave an in-depth description of the bird, but didn't mention this unusual feature. Then I read a doctoral thesis on the evolution of flightless birds from dinosaurs that somehow overlooked this one immediately relevant detail as well. I even presented my find to a handful of evolutionary biologists at Talk.Origins, who didn't believe me until I showed them the pictures! But there it is.
There were those who said that it couldn't have a claw in its adulthood. And I when I suggested that other ratites might have claws as well, (as an remnant of their dinosaur heritage) there were more skeptics. But I looked into it at length and finally found out that the ostrich had much more than that. Ostriches have claws at the end of three actual saurian fingers on each wing! Well in that case, why aren't they still dinosaurs now?
And its not just ratites and hoatzins that have these.
I found lots of other birds that did as well!
And as far as I can see, the size, shape, and proportion of every other bone is exactly the same. The only significant differences between the two are the arms and tail. Both are underdeveloped in the emu, almost like a birth defect that continues generation after generation. And that's essentially what evolution is; a variant trait that is perpetuated throughout the new population. And unlike "modern" birds, emus lack the keeled sternum of neognaths (flying birds). Even their skulls are different. Ratites have skull sutures that are sealed in neognaths to strengthen them for sustained flight. This makes them even closer to the skeletal structure of the dinosaurs they obviously came from. And it gives them the appearance of being a transitional species between the two.
The vertibrae of every bird's tail are fused together. And creationists like to cite that as being an insurmountable difference between these major taxanomic classifications of life. But they fail to realize that many dromeaosaurs, (including the now famous Velociraptor) also had fused vertibrae in their tails, both at the tip and at the hip. So what they hoped would be a defining distinction is in fact another distinct similarity between Dromaius novaehollandiae (emu) and Dromiceiomimus.
Skeletally, emus are an almost exact match for a therapod dinosaur called Dromiceiomimus, which means "emu-mimic". Dromiceiomimus is a bit taller than an emu, but so far as I can tell, the skull is identical, right down to the beak with the nostrils way out at the tip. (Flying birds and penguins both have the nostrils up closer to the eyes).
The other reason that this enigmatic claw was important is that Biblical literalists insist that birds are not related to dinosaurs, believing them to have been magically created seperate from, and therefore unrelated to, any other order of animals. However, birds with claws in their wings serve as evidence to the contrary. Because clawed fingers on functionless limbs serve no purpose of intelligent design. But they do serve as pretty sound evidence these were once saurian arms.
These claws also represent a feature that creationists insist cannot exist; a truly vestigial limb, something that would not exist unless these animals evolved from a form that had use of that limb. But emu wings are utterly useless. They can barely move their arms at all. And they serve no purpose whatsoever in their present state. The presence of a claw only adds insult to injury for their case, because what good is a weakly attached claw on a frail wispy arm that can't do anything?
But creationists contest evolutionary evidence on the claim that avian and saurian structures differ so significantly, that one could not have beget the other. But I know that these supposedly fundamental differences are greatly exaggerated. Birds of any kind already look an awful lot like therapod dinosaurs. Nothing else has the kind of feet and legs that dinosaurs and birds share in common, for example. Both are hemeothermic. Both lived, moved, ate, bred, and nested in exactly the same way. And that saurian similarity is especially true in the case of emus and their close cousins, the ostriches and cassowaries. All of whom are the closest things on Earth today to what the dinosaurs once were.
Emus are ratites, (paleognaths) the most ancient of all extant birds. The ratite line also includes cassowaries, rheas, ostriches, and even kiwis. They are not only the largest birds alive today, but the largest birds that have ever lived, including the New Zealand moahs and the giant elephant bird of Madagascar, both over ten feet tall, and both driven to extinction within the last few centuries. And all of them looked more like dinosaurs than anything that ever lived since the Mesozoic era.
Dromiceiomimus had no teeth in its bill, indicating that its diet was likely similar to my emu as well; eating seeds, bugs, and the like. Such a diet means that the clawed forearms are completely unnecessary. But they do have weight and that weight is equal to the weight of the tail, which exists solely to counterbalance the arms.
Tyrannosaurus, the most famous therapod, (and probably the most famous dinosaur, ever) came along at the very end of the Cretaceous period with arms so tiny as to be virtually useless. Unlike all the other carnivorous dinosaurs who use their arms in seizing prey, Tyrannosaurus relies entirely on its mouth to hunt, just like my emu. Without purpose, the arms of the T-Rex have atrophied to superfluous appendages and even lost digits. The T-Rex of 65 MYA had only two fingers on each of its (relatively) tiny arms. The modern emu has slightly smaller arms (proportionately) with only one finger each. The T-Rex still needed the long tail to counterbalance that huge head. But the ratites have small dromeaosaurid heads with tiny T-Rex like arms, so the tail isn't needed at all.
In an small group, isolated from the rest of the gene pool, such apparent defects as this would have a much better chance of influencing the remaining population. Since longer arms and tail are unnecessary for these particular creatures to survive and thrive, then these extremities would eventually be removed from the descendant gene pool anyway, resulting in something that looks exactly like an emu.
Even the emu's feathers are antiquated, with long hair-like strands. And we now know that at least a few therapod dinosaurs called dromeosaurs (includes Dromiceiomimus) also had feathers of one sort or another. Something that would be unlikely in the extreme, were they not related.
Sinosauropteryx prima had the same kind of hair-like proto-feathers that an emu has a chick. Some of Caudipteryx zoui's plumage was similar to what the emu has as an adult. Emu feathers, (like those on Caudipteryx) were symmetrical, unlike those of flying birds.
Caudipteryx also had the "half-wing" that so many creationists have insisted could never be found! And that half-wing also had a claw in its fossil impression that was very much like the one on my emu's arm!
Fossilization rarely ever occurred. The vast majority of life on Earth died without leaving any trace at all. Finding fossilized feathers is especially rare, because their very lightweight and delicate structure makes it even more difficult for that process to occur. And if a feather should fossilize on its own, it would be impossible to mate it to a particular bird or dinosaur. So basically, unless it is a well-preserved, complete, and even lithographic image, it won't reveal plumage of any kind. But that was exactly how Sinosauropteryx prima, Caudipteryx zoui, Confuciusornis sanctus, and other feathered dromeosaurids were all discovered, including the oldest bird known to man, Archaeopteryx lithographica. The proof of each transitional species cast in stone.
And finally, there is the case of the oviraptor, one of the therapod dromaeosaurs, (shown above adorned with emu-type plumage)
It is not yet known whether the oviraptor had feathers or not. But there is considerable circumstantial evidence to suggest that it did. It had a toothless beak, and was otherwise quite bird-like, not only in skeletal structure and appearance, but in behavior as well. In what has to be the most unusual and informative fossil finds ever, we see that oviraptor actually sat on her nest, in the same pose as a mother hen. This is a defining discovery because it answers one of paleontology's toughest questions to answer with certainty. "Were dinosaurs warm-blooded?" And now we know for sure that they were.
It also answers one of creationist's most severe challenges against evolution; "What good would a wing be, if it were too small to fly with?" Well for one thing, they make marvelously colorful displays in their courtship dances, (which is what ostriches still use theirs for) but as we see in this nest frozen in time, they also made it much easier to shelter and insulate their eggs, (increasing the survivability of even a large clutch). Critics of evolution think that wings are only useful for escaping predators. But they were key factors for the hens in their nests, and critical status symbols for cocks to attract mates. And these are both much more powerful evolutionary influences than the ability to fly!
Finally, this fossil also shows that dinosaurs nested like birds, which means they cared for their young like birds. And on the whole, it shows that they very nearly were birds! So why do creationists resist the idea of birds evolving from dinosaurs?
An artist's impression of Oviraptor brooding over her nest, an image inspired by the actual fossil find of that very pose (at right)..
Notice the position of the eggs under the right arm, rather pointless if there were no insulating feathers, don't you think?
One of my curious neighbors
Only 4 monts old, and
already over four feet tall!
How should such a miniscule, micro-evolutionary, *decrease* in genetic "information", possible even within a single generation, equate to a supposedly impossible macro-evolutionary leap in the eyes of creationist critics?
This is no insurmountable mathematics improbability, nor is it in violation of any universal physical law.
In fact, this may be the most common of all visible birth defects.
Yet any creationist who reads this will chant; "No no no. It just can't be". "End of discussion".
Even though the hook-shaped claws, on wispy frail and useless, (obviously vestigial) arms of these 6 foot tall Eocene birds
clearly indicate a less-than-infallable and even incidental, (as opposed to intelligent or purposeful) design.
And they give silent, but certain testimony as to their ancestral origins, no matter what any of us would prefer to believe.