Its Name Is Methuselah. That's Oh-So-Appropriate

Methuselah isn't a hyperbolic name for one Australian lungfish at Steinhart aquarium in San Francisco. She was known to be incredibly old, as her documented life began in 1938, when she was one of 232 fish transported via steamship from Australia to the US. Now a new study indicates Methuselah is likely the oldest fish currently living in captivity, at somewhere between 92 and 101 years old. The Guardian reports she—how the aquarium refers to her, though in one of many quirky details about Methuselah, her sex can't be confirmed until after death—is so old scientists couldn't reliably date her using radiocarbon.

So they used a "harmless methodology" to land at the estimate, per a statement from the California Academy of Sciences. Researchers removed a fin clip smaller than a pencil eraser in size and extracted her DNA from it. LiveScience translated the process that followed: "The team analyzed the amount of methylation in the fishes' genetic material. Methylation is a biological process by which methyl groups—a carbon atom bound to three hydrogen atoms—are added to the DNA molecule. From this, they were able to work out how long it would have taken for Methuselah to build up the number of methyl groups found in her DNA."

"Although we know Methuselah came to us in the late 1930s, there was no method for determining her age at that time, so it's incredibly exciting to get science-based information on her actual age," says Charles Delbeek, Curator of Aquarium Projects at Steinhart Aquarium, in a statement. The Guardian shares a slew of quirky details about lungfish in general, calling them "a species more closely related to humans or cows than to ray-finned fish like salmon or cod" and noting that the 43 billion base pairs that make up their genome far outpace the 3 billion-or-so that make up our own. (More discoveries stories.)