Biologists at the California Academy of Sciences said Methuselah, who weighs 40lbs, was brought to the San Francisco museum in 1938 from Australia.

She is being given the "best possible care" and "hopefully thrives" - but can be "a little picky" with her food.

A primitive species with lungs and gills, Australian lungfish are believed to be an evolutionary link between fish and amphibians.

She likes fresh figs and belly rubs

The Australian lungfish is a threatened species but the museum has two others which are younger and believed to be aged in their 40s or 50s.

Methuselah likes to eat fresh figs, get belly rubs and is named after the Biblical figure, Noah's grandfather, who was said to have lived to be 969-years-old.

Her first appearance in the San Francisco Chronicle was in 1947: "These strange creatures, with green scales looking like fresh artichoke leaves, are known to scientists as a possible 'missing link' between terrestrial and aquatic animals."

The previous oldest Australian lungfish on record was at the Shedd Aquarium in Chicago - but died in 2017 at the age of 95.

"By default, Methuselah is the oldest," said Allan Jan, senior biologist at the California Academy of Sciences and the fish's keeper.

Methuselah's caretakers believe the fish is female, although it is difficult to determine the species' sex without a risky blood draw.

The academy is planning to send a tiny sample of her fin to researchers in Australia, who will try to confirm the sex and determine the fish's exact age.

Mr Jan said Methuselah likes getting rubbed on her back and belly and has a "mellow" personality.

He added: "I tell my volunteers, pretend she's an underwater puppy, very mellow, gentle, but of course if she gets spooked she will have sudden bouts of energy.

"But for the most part she's just calm.

"We just give her the best possible care we can provide, and hopefully she thrives."

Jeanette Peach, spokeswoman for the California Academy of Sciences, said: "She's a little picky and only likes figs when they are fresh and in season.

"She won't eat them when they're frozen."