A SWELL shark egg has hatched a pup, despite being found in a tank with no males, stunned researchers at a Louisiana aquarium have announced. The miraculous 'virgin birth' discovery was first made eight months ago. Though the aquarium's husbandry team say the egg could have gone unnoticed for an additional two months prior.
![[Yoko, a swell shark born to a female who hadn't been near a male in three years.]](https://www.thesun.co.uk/wp-content/uploads/2025/01/yoko-swell-shark-born-female-967536083.jpg?strip=all&w=587)
The swell shark pup, called Yoko, hatched on 3 January, and has been closely monitored ever since. "We’re thrilled to announce the hatching of a new swell shark pup - without a male present," the aquarium wrote in a Facebook post. "Our team determined that the two female sharks residing in the tank had not been in contact with a male in over three years.
"This does suggest that either a phenomenon called parthenogenesis, a rare form of asexual reproduction, or delayed fertilisation, where fertilisation occurs long after mating, may have occurred.". Parthenogenesis - how so-called 'partho babies' are born - is natural form of asexual reproduction in which an embryo can grow from an unfertilised egg.
Its a natural phenomenon has been observed in more than 80 species, from bees, to fleas, to scorpions and lizards. Though researchers note that young sharks born in such extraordinary ways can face significant challenges, and may not survive to adulthood.
The pup will undergo DNA tests to determine whether it is a true 'partho baby' or a result of delayed fertilisation. “This situation is incredible and shows the resilience of this species,” said Greg Barrick, the curator of live animals at Shreveport Aquarium.
