Huge mystery as 'virgin' shark gives birth despite living in an all-female tank

A bizarre mystery has emerged after a shark gave birth while living in an all-female tank.

Staff at Shreveport Aquarium, in Louisiana, were stunned when a young swell shark (Cephaloscyllium ventriosum) hatched without any male sharks present.

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The egg was first identified eight months ago and was later thought to already be in the tank two months prior.

Then at the start of the month (3 January), the swell shark - name 'Yoko' - successfully hatched, surprising everyone.

Aquarium staff said the two female sharks in the tank, one of them being Yoko's mother, hadn't been in contact with a male for over three years.

And given that the gestation period of swell sharks is between nine and 12 months, Yoko must have been conceived in a different way.

How was Yoko conceived?

Aquarium staff were stunned when the young swell shark was born in an all-female tank (Shreveport Aquarium)

The aquarium has two possible answers to how a 'virgin' shark gave birth.

One is something called parthenogenesis, which is a rare form of asexual reproduction.

And the second is delayed fertilisation, where fertilisation occurs long after possible mating.

"To confirm the exact cause, the husbandry team will take steps to karyotype the pup once it is a suitable size for a blood draw, likely after a few months," Shreveport Aquarium said.

"This DNA analysis will provide definitive confirmation of whether the hatchling is a product of parthenogenesis or delayed fertilisation."

Greg Barrick, the Curator of Live Animals at Shreveport Aquarium, added: "This situation is incredible and shows the resilience of this species.

"We are very excited in the coming months to confirm whether this was indeed a case of parthenogenesis or if it was delayed fertilisation. It really proves that life... uh... finds a way."

How is Yoko getting on?

Yoko might not live for too long (Shreveport Aquarium)

The small shark, named after the Chumash word for shark, is said to be 'thriving' in current conditions.

However, the aquarium has warned that when young sharks are born through 'such rare reproductive events' they can 'often face significant challenges'.

"Should Yoko's time with us be brief, it will still leave an unforgettable legacy, contributing invaluable insights to the study of shark reproduction and conservation efforts," it added.

"Yoko is currently being closely monitored off exhibit to ensure its health and well-being.

"While visitors cannot see the pup in person just yet, the aquarium is excited to share its progress on social media until the pup is old enough to move to a larger tank."