One odd thing about Methuselah's lifespan is that, while the Masoretic text (the standard Hebrew text nowadays) says that he died in the same year as the Flood, the Septuagint claims that he lived for fourteen years after the Flood. Was this a mistake in the text translated for the Septuagint, or did the transcribers of the Masoretic text correct what they saw as a mistake in earlier versions? I guess there's no way to tell anymore, short of Enoch coming down from Heaven to provide the answer.
Methuselah's first-born son, Lamech, didn't live anywhere near as long as his father, with the Bible reporting that he died at the age of 777. Still a long time, but shorter than any of the other recorded antediluvian lifespans except for that of Enoch, who apparently never actually died. But I suppose the significance of the number seven means that SOMEONE had to die at that age. Seth's descendant Lamech is not given much background in Genesis, but his counterpart in Cain's line is. This Lamech had two wives, killed a man for hitting him (so much for "turn the other cheek," although in fairness Jesus wouldn't be around to tell anyone that for another 4000 years or so), and claimed that he would be avenged seventy-seven times if anyone killed him. His children were Jabal, Jubal, and Tubalcain, whom I mentioned in an earlier post in this series.
In Genesis 6:3, God limits the lifespan of humans to a mere 120 years, which is actually a pretty good guess. According to Wikipedia, there's only human who's been recorded to have lived longer than that. This person would be Jeanne Calment, who died in 1997 at the age of 122 years and 164 days, which would still round down to 120 if you're going by tens. Nonetheless, the limit doesn't seem to take right away, as there are plenty of characters in the early books of the Bible who live considerably longer than that. Lifespans do decrease gradually, however, and I don't believe anyone after Moses (who is said to have lived exactly 120 years, while his brother Aaron died at 123) is said to have lived that long. I've seen some apologists suggest that 120 years is actually the length of time that Noah spent preaching the coming flood and building the ark, which makes him seem rather pathetic. I mean, 120 years as a prophet, and not a single convert outside his immediate family? Well, we'll see more of Captain Noah and his magical ark next week. Maybe he'll sing a rainbow.