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The Case of the Mysterious Hoatzin: Biogeography Fails Neo-Darwinism Again

Casey Luskin


In 2009, the National Center for Science Education’s Eugenie Scott suggested that scientists should not admit when the evidence contradicts some evolutionary hypothesis, but should rather say that it “sheds new light on this part of evolution.” Since then, I’ve kept an eye out for that and similar language.

For example, a recent article on Science Daily was titled “Across the Atlantic on Flotsam: New Fossil Findings Shed Light on the Origins of the Mysterious Bird Hoatzin.” According to the article, hoatzins lacked a known fossil record outside of South America until recently, when “a team consisting of German, Brazilian and French researchers … not only described the earliest known fossil find of the mysterious bird group, but has also produced the first proof outside of South America.” Apparently, the fossil bones from Namibia, Africa are about 17 million years old and have the right characteristics to identify them as belonging to hoatzins. However, finding extinct hoatzin-like birds in Africa poses a problem for Darwinian biogeography. I’ll let the article explain:

When two related animal groups are discovered on different continents, this can be explained in principle by two mechanisms: either the continents were once connected by land, or the distribution took place directly across the water.

Africa and South America were once part of a supercontinent called Gondwana, but this had already broken up much longer than 20 million years ago, the continents being separated by the Atlantic. So Hoatzins must have crossed the ocean at some stage in order to get from one continent to the other.

But how does a bird, which is an especially poor long-distance flyer, manage to cross a sea that is over 1,000 kilometres wide? Even if the flying capabilities of the Hoatzin’s ancestors were better, it is highly unlikely that they could have managed this distance in the air.

Gerald Mayr and his colleagues from Brazil and France have an explanation that is somewhat unexpected for birds: “We assume that the bird crossed the Atlantic upon drifting flotsam.” This means of travel using flotsam is already familiar with regard to some primates, rodents and lizards, but it would be the first proof of a similar journey by a bird.

OK, I get it: when common descent cannot explain observed biogeographical data, just assert that your organism rode on rafts across vast of kilometers of ocean, and presto — your problem is solved. And of course you can’t have just one rafting hoatzin — there must be at least two (or perhaps one brought its clutch of eggs along on the raft for the voyage?) — or your rafting hoatzin will become an evolutionary dead end.

The authors don’t think the rafting hypothesis is a problem since, supposedly, we’ve already seen that “primates, rodents, and lizards” did the same thing. But what’s the evidence that primates, rodents, and lizards crossed oceans on rafts? As I explained here or Jonathan M. explains here, the evidence again is biogeographical data that refutes common descent.

With primates, for example, new world monkeys are said to be descended from African monkeys. But new world monkeys appear in South America at a time when the continent was separated from Africa by 1000+ kilometers of ocean. Proponents of common descent aren’t worried: they can just create myths about seafaring monkeys to solve the problem. Never mind that monkeys have high metabolisms and it’s hard to imagine how they could possibly survive such a trip.

Another recent article at BBC News notes that this same problem besets evolutionary thinking about South American rodents:

No-one really knows how they got there, but scientists have speculated that some small animals could have made the journey by sea.

“They could have got there on some raft of vegetation,” said Dr Croft.

“That maybe sounds like a fantastic tale, but in fact we do see things like this happening today. You can get big logjams of vegetation that get pushed out of rivers during storms, and often you will see mammals on them.

“The odds of them making this crossing are obviously very low, but after millions and millions of years the odds of some animals making it go up considerably.

Let me get this straight: Since we know that common descent is true, and since the rodents, monkeys, and hoatzins exist on continents separated by vast spaces of ocean with no land-based migrational pathway, the fantastic rafting tale must be true.

Rats caught in shrubs for a couple days after a storm, perhaps. But do we observe mammals or birds rafting across oceans?

If two similar species separated by thousands of kilometers across oceans cannot challenge common descent, what biogeographical data can? The way evolutionists treat it, there is virtually no biogeographical data that can challenge common descent even in principle. If that’s the case, then how can biogeography be said to support common descent in the first place?


Casey Luskin

Associate Director, Center for Science and Culture
Casey Luskin is a geologist and an attorney with graduate degrees in science and law, giving him expertise in both the scientific and legal dimensions of the debate over evolution. He earned his PhD in Geology from the University of Johannesburg, and BS and MS degrees in Earth Sciences from the University of California, San Diego, where he studied evolution extensively at both the graduate and undergraduate levels. His law degree is from the University of San Diego, where he focused his studies on First Amendment law, education law, and environmental law.



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