Virgin Births: Scientists Baffled On Female Zebra Shark Gives Birth Without Mating

A female zebra shark known as "Leonie" and confined for years without a partner has given birth to many offspring. This astounded the scientists and said they do not know how this strange thing happens.

This is the first female shark ever recorded that reproduced asexually after mating with a male three years ago. Leonie lived with a male partner at the Reef HQ aquarium in Townsville, Queensland, between 2006 and 2012. It was later moved into a separate tank by the aquarium for space reasons. Then, in April 2016, Leonie hatched three eggs without even mating with its partner, according to CNN.

The findings on Leonie's behavior were printed in the journal Scientific Reports. It was led by Dr. Christine Dudgeon, a postdoctoral researcher at the University of Queensland in Australia and other colleagues.

The scientists have been observing "virgin births' in some vertebrates like reptiles, rays and sharks in the past. Dr. Dudgeon said that this could really be surprising. On the other hand, she said that there is nothing miraculous about it. She explained that this form of asexual reproduction known as "parthenogenesis" is quite common in invertebrates. However, she said that it is exceedingly rare (at least in captivity) for sharks to reproduce asexually and it is not fully understood.

The team sees a couple of various mechanisms that may lead to the genetic signatures. The researchers thought that Leonie could be storing sperm. On the other hand, when the team examined the pups and the possible parent sharks using DNA fingerprinting, they found the pups only had cells from Leonie, according to Huffington Post.

In Leonie's hatchlings, more genes are identical and less diversity referring to that they had been produced asexually instead of sexually through sperm storage. Hamish Tristram, a senior aquarist with Reef HQ, described it as definitely surprising. He further said that she had been mating successfully for several years and there was nothing much published about such large animals switching reproductive strategy so quickly.

Tristam explained some theories regarding Leonie's sudden unusual behavior. He said that one theory is that in the wild, if for some reason males cannot have contact with the females for one breeding season. He further said that they can keep their lineage going for one or two seasons (through asexual reproduction) until they can reproduce the traditional way. On the other hand, the genetic diversity of animals gets really reduced using this method and long term, they need to diversify to help them adapt to their environment, according to Dudgeon.