Another Failed Evolutionary Prediction

A fossil cast of a Protoceratops nest (click for credit)

A fossil cast of a Protoceratops nest (click for credit)

According to the currently-fashionable hypothesis, dinosaurs evolved into birds. Indeed, some evolutionists take this to such an extreme that they say things like:

Birds Are Living Dinosaurs

While there are some evolutionists who disagree with this hypothesis, it is part of the current scientific consensus. Of course, for a hypothesis to be considered scientific, it must make predictions that can be confirmed by the data. The more its prediction are confirmed, the more reliable it becomes. The more its predictions are falsified, the less reliable it becomes.

Indeed, one of the reasons I consider the creation model to be very strong is that it has made several predictions which have been confirmed by the data (see here, here, here, here, here, here, and here, for example). The evolution model, however, has made many predictions that have been falsified by the data (see here, here, here, here, and here, for example).

The hypothesis that dinosaurs evolved into birds has been used to make a prediction about the time it took for dinosaur eggs to hatch, which is typically referred to as the incubation period. We can’t directly measure the incubation period of dinosaur eggs, but many evolutionists have assumed that it must be similar to that of birds, which is quite different from that of reptiles. For example, Dr. Kenneth Carpenter wrote a book entitled, Eggs, Nests, and Baby Dinosaurs: A Look at Dinosaur Reproduction. On page 200, he suggests that the incubation period of dinosaur eggs should be similar to that of birds. He shows how bird egg incubation period varies with mass and then writes about a particular dinosaur egg:

…with an estimated live weight (i.e., as it might have been 70 million years ago) of 152 g, would have an estimated incubation time (from time of egg laying until hatching) of thirty-five days.

Similarly, on page 266 of Biology of the Sauropod Dinosaurs: Understanding the Life of Giants, we read:

The amount of time necessary for a dinosaur embryo to mature to the hatching stage may never be known with certainty, but it can be at least roughly estimated by a model developed by Rhan and Ar (1974) for birds. On the basis of comparisons with extant birds that have, in contrast to modern reptiles, a rather constant incubation temperature of about 40 oC, a dinosaur egg of 1.5 kg – the size of an ostrich egg – would require an incubation time of about 60 days to hatch.

The latest research indicates that such predictions aren’t anywhere close to being correct.

Gregory Erickson and his colleagues recently published a report in which they made what seems to be a reliable estimate of the incubation period for two dinosaurs: Protoceratops andrewsi and Hypacrosaurus stebingeri. The former laid eggs that were about 200 g, while the latter laid eggs that were about 4 kg. Based on the prediction that dinosaur egg incubation periods were similar to that of birds, the Protoceratops egg should have taken about 40 days to hatch, while the Hypacrosaurus egg should have taken about 80 days to hatch.

Erickson and his colleagues found that the incubation periods were more than twice as long as predicted. Protoceratops eggs took about 83 days to hatch, while Hypacrosaurus eggs took about 170 days. This is on par with the incubation periods for reptiles, not birds. From an egg incubation period standpoint, then, dinosaurs were significantly more like reptiles than birds.

How did Erickson’s team determine those incubation periods? They examined fossilized embryos and used a CT scanner to analyze the developing teeth. They found lines (called incremental lines of von Ebner) that are typical of any animal with teeth. These lines are laid down daily in all existing animals that have been studied, so counting the lines tells you the number of days the embryo’s teeth had been developing before fossilization. Is this an exact measure of the incubation period in these dinosaur eggs? Not really. It’s possible that the lines weren’t laid down daily in dinosaur teeth. In addition, animal embryos don’t form teeth right away, and many produce initial teeth that are reabsorbed. Thus, the authors had to make some assumptions about such issues in order to get the total incubation period.

Nevertheless, it seems that this study gives us the best estimate of the incubation periods for two species of dinosaur, and they are radically different from what was predicted based on the “birds are living dinosaurs” hypothesis.


  1. Jake says:

    I think I really don’t get biology: I assume the way one would model egg incubation times is by measuring such times for eggs of various sizes from multiple species and fitting to/theorizing some curve. Or maybe there are several classes of self-assembly mechanisms depending on the organism, so that one could say something like, “Birds and dinosaurs both have this particular type of body, which must develop along these lines.” Because it feels to me like the evolutionist doesn’t have enough information to make a prediction here: why couldn’t birds that are or are descended from dinosaurs just have a different incubation process, just because that’s how evolution changed things? I mean, I guess if you want to say birds aredinosaurs, and all dinosaur eggs must function the same way, then you run into trouble. Or is this more of an Occam’s razor question – evolution would be more elegant if dinosaurs and birds had analogous incubation times, so that there are fewer things to explain? To me it seems like there are so many possible factors that it’d be no surprise if naive parsimony didn’t work. And the study suggests that birds evolved shorter incubation times so that they’d be in a vulnerable state for less time. That isn’t an explanation, of course, but that it’s so easy to suggest such a thing makes me wonder how one exactly comes up with an evolutionary prediction. It seems an awful lot like evolution can be made to explain anything – and can hence predict nothing.

    1. Jay Wile says:

      I think you do understand biology, Jake. The method you describe was done by Rhan and Ar back in 1974 for birds. They found that while there was some scatter, in general, an equation could be worked out to predict the incubation period of a bird’s egg with an accuracy usually better than 20% based only on its mass. The “birds are living dinosaurs” crowd simply took their hypothesis to its logical conclusion. Incubation period is closely related to metabolism. If birds are living dinosaurs, their metabolisms should be similar to dinosaurs, so their incubation periods should be similar.

      Now, of course, as you say, evolutionists can just conclude that “evolution works in mysterious ways,” so while birds are living dinosaurs, dinosaurs aren’t very similar to birds in their incubation period. The point of the post, however, is that one evaluates a scientific hypothesis based on its predictions. In this case, the prediction failed, which adds further doubt to the hypothesis.

      1. Jake says:

        I think what I was confused about was whether this was a failed prediction or a bad prediction – i.e., one that, if an evolutionist were paying attention to the scope of the theory, he/she wouldn’t have been confident of. The shared metabolism argument does seem to give a real prediction, in that metabolisms are probably much more difficult for evolution to change. I guess what I wanted to establish was that this was a failure of the theory and not just of the community’s use of it – to the extent that the two can be separated. (I think they can be, but I’m not sure that’s always a clear thing.)

        1. Jay Wile says:

          Your point is a good one, Jake. Often, a theory is misused by its proponents. However, there really did seem to be a consensus. Even the paper that I am discussing said, “Birds are living dinosaurs; their rapid development has been considered to reflect the primitive dinosaurian condition.”

        2. Jake says:

          I guess that’s the pertinent point here – that there was a consensus. That makes it a lot less likely that people are applying the theory inappropriately.

          I noticed that the paper says flat-out that “Birds are living dinosaurs,” and that surprised me; I figured you had gotten the quote from a less-serious source.

        3. Jay Wile says:

          That phrase is all over the place. I linked to a less serious source, but you can find it everywhere. Here it is in a letter to the journal Science.

  2. cjl says:

    I am thankful for your blog, Dr. Jay. It is so very hard to find this kind of reliable information in an information industry largely biased against anything that does not promote its own worldview. I am currently experimenting with your posts as a “home school curriculum” of sorts for me, my wife, and my infant kiddo! This would make my child, btw, a second generation Dr. Jay “reader!”

  3. Kenyatta says:

    Is it possible that some living reptiles today are descendants of ancient dinosaurs? Through the process of natural selection/adaption

    Not really related to the article, but I enjoy reading you blogs more than any other creation website. I like your position that interpreting the data is better than enforcing one’s belief. When is an app coming? I’d love to see an app for Android or iPhone

    1. Jay Wile says:

      I don’t really see how living reptiles can be descendants of dinosaurs, because there are some very fundamental differences in their skeletons. It’s hard to describe the details without a lot of jargon, but someone who knows skeletal anatomy can easily distinguish between the skeleton of a dinosaur and that of a living reptile. Even the teeth are significantly different. I don’t see how that many differences could be produced by natural selection/adaptation.

      Thanks for your kind words about my blog. I hadn’t really thought of an app. The site itself is mobile friendly, do I don’t see the advantage of an app.

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