Female sharks continue to give birth in the absence of males – and scientists say it’s a bizarre ‘survival mechanism’

FEMALE sharks are having babies with no male in sight – and scientists say the bizarre behavior holds clues to TKTK

Captivesharks at the Cala Gonone Aquarium in Italy have repeatedly produced offspring without the involvement of males.

And scientists believe this virgin birth may be a purposeful effort to maximize their chances of survival.

A to study published last month in the magazine Scientific Reports observes repeated asexual reproduction in two common sharks.

The creatures spent more than a decade away from the males of their species.

“However, an almost annual production of young was observed in the absence of males,” says the paper.

Since 2020, scientists believe that female sharks have undergone facultative parthenogenesis, the process by which unfertilized eggs develop into offspring.

Although this type of reproduction is thought to occur in fungi and bacteria, it has also been reported in vertebrates, including several species of sharks.

However, the repeated delivery of young is what intrigues scientists.

One proposed theory is that this type of asexual reproduction is an “adaptive reproduction strategy” that comes into play when females have limited access to males.

The phenomenon is called facultative parthenogenesis, or asexual reproduction that occurs in women who usually reproduce sexually.

In a biological context, it ensures that the species can continue regardless of population restrictions.

In the case of common smooth sharks, it’s easy to see how this strategy could be beneficial.

The sharks’ native range extends across the eastern Atlantic Ocean and the Mediterranean Sea, but they are increasingly at risk from illegal fishing.

The creatures are so threatened that the International Union for Conservation of Nature has classified them as endangered.

The researchers found that the two females could reproduce asexually approximately once a year, ruling out the possibility of sexual reproduction through stored sperm.

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The Italian sharks produced four pups, although only one born in 2021 was viable.

When reproducing sexually, they typically have a litter of four to 15 puppies.

The first cub born in 2016 died shortly after and its remains have not been studied, meaning scientists cannot definitively conclude how it was conceived.

Two other cubs born in 2020 and 2023, respectively, also did not survive.

And the terrible survival rate is not due to defects associated with low genetic diversity, contrary to what one might think.

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All of the young people had bite marks on their bodies, which scientists say is the likely cause of death for those born in 2020 and 2023.

Even the puppy born in 2021 suffered a “cranial bite” at birth, according to the newspaper.

The researchers collected DNA samples from the three remaining cubs and compared them to the genetic profiles of the adult females.

Miraculously, scientists discovered that the offspring shared unique genetic markers with their mothers.

“These findings greatly improve our understanding of shark reproductive strategies and can inform conservation efforts for threatened species,” the authors wrote.

Although more research needs to be done on the topic, scientists believe that facultative parthenogenesis could serve as a corrective measure in populations with declining numbers of males.