The Real Reason A Shark Just Had Babies Without A Mate

It's actually kind of sad.

When the Reef HQ aquarium in Queensland, Australia, decided to scale back its zebra shark breeding program because of space constraints, a zebra shark couple was separated.

Leonie's mate, Leo, with whom she'd had dozens of babies, was moved to another tank. This was back in 2013. Since then, Leonie has never seen a male shark.

But in the spring of 2016, even though she hadn't come into contact with a male shark since Leo left, Leonie laid some eggs - and they actually hatched. Two healthy zebra sharks, Cleo and CC, were born to Leonie in April, and they're entirely hers.

"Leonie had pups with a male leopard shark until 2013, when the breeding pair were separated for space reasons," Dr. Christine Dudgeon of University of Queensland'sSchool of Biomedical Sciences said in a statement. "In April 2016 Leonie hatched three eggs, despite having no access to a mating partner for three mating seasons."

Scientists are amazed by the first recorded instance of a shark reproducing without having sex - they recently published a study about it - but there's also something kind of sad Leonie's remarkable story.

Zebra sharks - also known as leopard sharks - are endangered after years of legal and illegal fishing for their fins, skin and meat decimated the population.

At first, after Leonie's eggs hatched, scientists thought Leonie was somehow storing Leo's sperm, until DNA tests showed that the babies were composed entirely of cells from Leonie - she was determined to keep her family going, even if she didn't have a mate.

According to Dudgeon, Leonie's ability to reproduce asexually "has big implications for conservation" - which is so important for the endangered animal. "Leonie adapted to her circumstances and we believe she switched because she lost her mate," Dudgeon said.

Scientists are now looking into whether similar asexual reproductions could be happening in the wild and whether Leonie's pups will be able to have pups of their own when the time comes - with or without a mate.

But reproducing without a mate is not a long-term solution for conserving zebra sharks. That's because lack of genetic diversity in the species wouldn't be very good for the health of the sharks in the long-run.


"You lose genetic diversity with generations of asexual reproduction, so we'll be seeing if these offspring can mate sexually themselves," Dudgeon said.

If zebra sharks can withstand unstable mating patterns, it could help them survive in wild habitats, which are becoming more and more treacherous because of overdevelopment along the coasts of Southeast Asia.

So when the aquarium was short on space for zebra sharks and decided to stop breeding Leonie and Leo, it almost seemed like a portentous metaphor for what's actually happening on the planet - there just aren't enough safe spaces for the amazing zebra shark.

To learn how you can help save endangered sharks like Leonie, click here.