Did ancient humans really live for hundreds of years, as mentioned in Genesis? What is your explanation?
In ancient Egypt, one did not have to be a centenarian in order to be accorded the honor of a 110-year-old. There is no ancient skeletal or palaeoanthropological evidence that any human ever lived to 120, let alone the neighborhood of 200 (Job 42:16), or a ripe 969 (Methuselah, Gen 5:27). The Egyptians considered 110 to be the ideal age. This would have been in distinction to one's actual age. We read that Imhotep, vizier under the Pharaoh starting in the 3rd dynasty, "lived to 110." In other words, he lived a perfect life. Joseph too lived a full and exemplary life in Egypt; thus we aren't surprised to find his age as 110 years (Gen 50:26).
Yet among the Israelites it was 120 that was considered the ideal age. Moses' lifespan is recorded as 120, even though he was apparently in excellent health (Deut 34:7). Was 120 an idealized age? Is it possible he lived only to 70 or 80 (Psalm 90:10)? The impression of an idealized age is especially plausible when we see that his life is presented in three periods of 40 years each.
As for the ages in the hundreds of years in Genesis 5, I think it is most plausible that these ages are idealized, based on a modified sexagesimal (base 60) system. 60 is a perfect number, and multiples of 60 take on significance (Noah aged 10 x 60; Moses ages 2 x 60; etc). There are parallels in the Sumerian king lists, where some live and reign into the thousands (and tens of thousands) of years (!). What's really going on?
If you want more, an excellent piece by Carol Hill will bring a lot of clarity to this matter. (A more technical mathematical analysis of sexagesimal counting will be found here.) Taking into account the Babylonian sexagesimal system, along with the Mesopotamian notion of sacred numbers, equips us to understand the meaning of the extreme longevities in antediluvian times.
Note: I did not give a real solution to this question in my book Genesis, Science & History, though the ideas in these articles I will be sure to include in the next version. -- DJ