A snake laying eggs might not seem to be the most unusual thing to happen.
But keepers at the Saint Louis Zoo in Missouri were surprised to discover that one of their ball pythons had produced seven eggs - despite having no contact with a male for over 15 years.
While some reptiles are known to reproduce asexually, keepers are also surprised by the mother's age.
At an estimated 62 years old, the ball python is believed to be the oldest living snake.
Mark Wanner, the zoological manager of herpetology at the zoo described the birth as a "unique occurrence".
"It's amazing, in my opinion, that a snake of this age is able to reproduce a fertile clutch of eggs," he told the BBC.
The snake was given to the zoo by a private donor in 1961 and was estimated to be three years old at the time, according to Mr Wanner.
The oldest documented ball python to date was a male at Philadelphia Zoo who died at the age of 47.
Mr Wanner added that the zoo planned to publish information about the snake's age and asexual reproduction, if and when it is confirmed by testing.
Three eggs have survived and remain in an incubator. They are expected to hatch within a month.
The zoo is using genetic testing to determine whether the eggs were produced asexually, which has previously been recorded in reptiles including ball pythons, rattle snakes and komodo dragons.
There have been previous cases of snakes storing sperm for delayed fertilisation.
Ball pythons, or royal pythons as they are also known, are native to central and western Africa.
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Reporting by the BBC's Victoria Bisset