What is "methuselahs"

Usage examples of "methuselahs".

Once the novelty wore off, these wide-eyed, gawking Methuselahs were viewed by most with a sort of in­dulgent amusement.

I'm almost as tall as you are now, and I've known for two years who you are, and I had guessed it before that-guessed that you were one of the Methuselahs, I mean.

I’m almost as tall as you are now, and I’ve known for two years who you are, and I had guessed it before that—guessed that you were one of the Methuselahs, I mean.