Lifespans Before the Flood: How Did People Live to Be 900 Years Old Before the Flood?

Many Bible readers feel puzzled when reading the genealogies in Genesis. They describe patriarchs living for hundreds and hundreds of years. Adam lived to be 930. His son Seth, 912. Methuselah 969. Noah 950. What’s going on here? Did ancient Bible writers just imagine these incredibly long lifespans? This would seem to be the case since people today only live into their 70s or 80s often with the help of modern medicine. These long lifespans must be mythical, right? Well… maybe not. Certain compelling reasons to believe that the biblical authors were recording the actual long lifespans of these patriarchs have persuaded trained geneticists to take these Genesis numbers at face value.[1]

The remarkable picture from these lifespans only emerges when plotting them on a graph. After all, a picture is worth a thousand words. Only then do we see that the average lifespan of these patriarchs who lived before the Flood lived an average of 912 years. After the Flood, their lifespans began systematically declining, following what’s known by biologists as a “biological decay curve.” A mythical list of ages would be unlikely to take such a predictable, exponentially declining curve. Noah, who was the 10th from Adam, lived through the Flood and died at age 950. Noah’s son Shem lived 600 years; his grandson 438 years. Five generations past Noah, lifespans decline to the 200s. Abraham, who was 10 generations after Noah, lived to be 175. We also have Jacob, when he was 130 years old, stating to Pharaoh that he had not lived as long as his ancestors. Jacob later died at 147. Several generations later we have Moses, living to be only 120.

What’s going with these lifespans? They systematically decline along a familiar-looking pattern that statisticians call an “exponential power curve.” Plotting their ages does not reveal a straight-line slope, but a curved one. They don’t suddenly bottom out right after the Flood, nor do they decline evenly. Rather, the lifespans decline along a nonlinear, exponential curve over time. And this curve literally passes every test for statistical significance. Whatever is going on here is not some chance occurrence. Their pattern breaks every possibility of being some fluke.

Geneticist Dr. John Sanford of Cornell University—who was part of a team that invented the “gene gun”—noted that these lifespans fit so tightly along this power curve that 95% of the lifespan variance is explained by the number of generations from Noah.[2] This statistical model matches the biblical data so closely that its likelihood of occurring by chance lies below one in a thousand. Now that’s uncanny.

This exceptionally strong correlation allows us to predict how long people would live based on how many generations they are from Noah. For example, the curve predicts that someone living 10 generations after Noah would have a 90% likelihood of living between 137 and 234 years. Similarly, it predicts with 90% certainty that a descendant alive 15 generations after Noah would live between 100 and 172 years. This model is so powerful that the average lifespans predicted by the model are within 10% of the actual lifespans recorded in the Bible! This close match reaches well beyond coincidence.

This leads to an even more stunning realization:  The lifespans in the biblical text span over 2,500 years of recorded history. And the original portions of Scripture that include these lifespans—Genesis 5 and 11—were produced by eyewitnesses whose lives overlapped one another for centuries and decades. So how in the world could they be faked? All of the original authors over numerous generations would have to be in on the scam, conspiring together to record lifespans that perfectly declined along an exponential power curve. Like that’s going to happen!

Thinking about that for a minute… why would they even want to do that? If you were going to make up some story about people in the past that you wanted your future readers to believe, why would you include such unbelievable lifespans? Making this “myth” explanation even less likely, whoever would fabricate this story must have understood advanced statistics. In addition, look at how the lifespans before the Flood are stable. They don’t follow ANY sloping trendline. The systematic decline only starts AFTER the Flood, suggesting that some aspect of the Flood event initiated the down-sloping power curve in lifespans. What was it?

Dr. John Sanford explains[3]: “The mathematical nature of the declining lifespans arose because the Biblical accounts are true, and are actually faithfully recording the historical unfolding of some fundamental natural degenerative process… The shape of the downward slope should be immediately recognized by any biologist. It is a biological decay curve. Noah’s descendants were undergoing some type of rapid degenerative process… there is now very strong evidence that humans are degenerating genetically, and have been for thousands of years, due to continuously accumulating mutations. This makes it very reasonable to conclude that the systematic degeneration of man that is documented in the Bible was due to mutation accumulation and resultant ‘genetic entropy.’”

A genetic bottleneck may well explain why mutations suddenly kicked into high gear. This occurs when a very small group of individuals become isolated from a once-larger population. The few individuals carry fewer genetic variations than their forebears. They now must build each generation using less information in their cellular blueprints. Biologists have watched lifespans decline after bottlenecks in various animal populations, from dogs to guppies.

The Genesis lifespan decay curve looks like real biology which points to real history. Books throughout the entire Bible, written by different authors in different timeframes, affirm this history. For example, Peter referred to “the days of Noah,” when “eight souls were saved through water.” Shrinking the entire human population down to eight was the ultimate genetic bottleneck in human history.

This Genesis-based trendline also points to a recent creation. Luke 3 lists a specific number of generations from Adam to Jesus, and the first names on that list coincide with the names in the Genesis accounts. The smooth, systematic decline in longevity leaves no room for hundreds or thousands of missing generations.

Even after learning about this amazing evidence in the Bible, many may still hold the popular but poorly defended position that ancient shepherds wrote their dreamed-up family history on animal skins. But it defies reason that ancient writers developed a text that spanned multiple generations, included over 20 lifespans that track over 2,500 years, and include two distinct and biologically relevant trendlines from the pre- and post-flood eras. Even so, how would the supposed shepherd pass off his forged history as real history to his own community leaders? Nobody gets away with that today. It would be impossible to collude such a statistical phenomenon over generations.

So, what are the implications that come from this? Well, for one, this shows that the whole of Scripture fits together, with several books from both the old and new testaments referring to these genealogies as authentic history. Even Jesus himself referenced by name Abel and Noah as though they were real people. Paul also referred to them historically, and even computed timespans based on these genealogies, treating them as real history.

What causes aging anyway? Biologists continue to investigate unknown aspects of aging, but largely agree that accumulated mutations within the body during one’s lifetime accompany the symptoms of aging, including wrinkled skin, weak bones, and loss of immune and other system efficiency. If God made Adam genetically perfect in the beginning, then no wonder his close sons and daughters could live so long.

The Bible also promises that Christ would be our “Kinsman Redeemer,” and breaking apart these genealogies would undermine the Gospel itself. Christ the Redeemer had to map back to Adam as the Bible promised.

These findings strongly support the historicity and veracity of the Bible, especially the book of Genesis. They suggest that although the longevity of the early Patriarchs seems extreme from our perspective, it could have been normal for them. The declining lifespans of the post-Flood patriarchs was due to the ongoing degeneration that resulted from Adam and Eve’s Fall and were accelerated by the genetic bottleneck caused by the Flood. The drastic decline in lifespans immediately following the Flood also supports the worldwide extent of the Flood, refuting ideas that it was ordinary or local. Because the genealogies and lifespans are linked, they validate the tight father-to-son nature of the genealogies, without gaps, leading to Adam and Eve living just thousands of years ago.


[1] A search for “genetic entropy” here reveals a plethora of articles on this topic:

[2] See:

[3] Sanford, John, Jim Pamplin & Christopher Rupe, “Genetic Entropy Recorded in the Bible?” (FMS Foundation, 2014) 3-5