Hi, Steven —

Not necessarily. What's interesting is that the life spans gradually decrease after the flood, and settle on a number that is reasonable to our science. For example, Genesis 6:3 says,

3 Then the Lord said, "My Spirit will not contend with man forever, for he is mortal; his days will be a hundred and twenty years."

The longest documented human lifespan is 122 years. Also compare Genesis 5 with Genesis 11. Psalm 90:10 says,

10 The length of our days is seventy years— or eighty, if we have the strength; yet their span is but trouble and sorrow, for they quickly pass, and we fly away.

Psalm 90:10

So while it's certainly possible to understand the life spans as symbolic — for example, indicating that sin was taking a toll on the human race — Scripture does quite deliberately move to more expected life spans, sometimes in the same text.

It's a scientific question whether an ancient human ancestor could possibly live 900+ years.

I don't think there is any evidence that any animal today has ever lived close to that;
the mid-200's is the longest I'm aware of. Plants of course can live that long.

Personally, I'm not going to make any a priori judgments about this matter.

Eric