Radiocarbon Dating and New Zealand Rats

Almost anyone familiar with the debate over the age of the earth is familiar with radiometric dating: testing for the existence of various atomic isotopes in a substance, then using the determined amount to extrapolate an age for the substance.

Radiocarbon dating of rat bones from New Zealand raises the issue of just how “foolproof” this radiometric dating method is.

Creationists have long pointed out the numerous problems in radiometric dating, including the underlying assumed rates of decay, amount of initial concentration, presumption of a closed system, and so forth. Interestingly, this week, radiocarbon dating of rat bones from New Zealand raises the issue of just how “foolproof” this radiometric dating method is.

The history of rats on New Zealand, while not a grade school topic, is important to the anthropologists who have tried to determine just when humans reached New Zealand. According to the commonly accepted theory, rats were stowaways (or perhaps brought as food) on the boats of the Polynesian explorers who first reached New Zealand. Thus, based on the 1996 carbon-dating of rat bones, some anthropologists concluded it was as early as 200 B.C. when the first humans (and rats) reached the islands.

But wait! That study has been controversial, because anthropologists have found no legacies of human settlement that would date to that time period. Instead, other anthropologists believe it wasn’t until the 13th century that rats and humans arrived. But what to do with the carbon-dating results from the 1996 study? Simple: it must have been a lab error, these anthropologists argue.

In search of a verdict, paleoecologist Janet Wilmshurst of New Zealand’s Landcare Research has used a new preparation technique to radiocarbon date rat bones from the same excavation site of the bones used in the 1996 study. The result? The new tests indicated that all the bones were from the year 1280 or later. Next, Wilmshurst’s team tried the new technique on the same bones used in the 1996 study. This time, all the bones dated to—you guessed it!—later than 1280. Finally, the team chose to date ancient seeds thought to have been gnawed by the rats (from the same excavation site). The seeds all dated from 1290 or later.

Answers in Genesis doesn’t have a particular opinion on when rats arrived in New Zealand, though the Bible tells us that humans would have arrived after the dispersion at Babel. Given that the dispersion happened midway through the 23rd century BC, this leaves more than 3,000 years, based on this new research, for humans to have found their way to New Zealand—clearly sufficient time.

Radiometric dates that fit scientists’ presuppositions are upheld without question.

But most interesting is the treatment of the radiocarbon dating results. How often do we read that scientists have “dated” a rock or fossil to a certain age, with the date then touted as absolute, unquestionable, etc. (and anyone who refutes it considered unscientific)? Yet here is a prime example of one of the many flaws in radiometric dating: the fallibility of preparation techniques. This is in addition, of course, to our criticism of the faulty underlying assumptions of radiometric dating.

What we consistently see is that radiometric dates that fit scientists’ presuppositions (such as the assumed evolutionary timetable) are upheld without question, but those that contradict other lines of evidence—including other calculated dates—are challenged and usually forgotten, often with “lab errors” and “contamination” taking the blame.

So next time an evolutionist friend tries to tell you about how radiometric dates “prove” how old the earth is, how old fossils are, etc., just answer that you think you smell a rat!

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