Australia's Reef HQ aquarium had hoped to scale back its shark breeding program. Its female sharks had other ideas.
Over the course of six years, Leonie, the zebra or leopard shark, had produced more than two dozen offspring before she was separated from her mate in 2012. But in 2016, Leonie — who hadn't been introduced to another male — laid eggs which produced hatchlings, reports New Scientist.
While sharks are known to store sperm for up to four years, per the Guardian, these hatchlings contained DNA from Leonie only. In essence, she made the offspring herself, marking the first time a switch from sexual to asexual reproduction had been witnessed among sharks, researchers explain in Scientific Reports.
Asexual reproduction itself is not so unusual; when males are scarce, it lets species from snakes to turkeys survive until mates can be found. But it "reduces genetic diversity and adaptability" and leads to "extreme inbreeding," says study author Christine Dudgeon.
One of Leonie's offspring, which had never reproduced sexually, also produced hatchlings using eggs fertilized by a cell known as a polar body.
But it was Leonie's switch from sexual to asexual reproduction that was a "really big surprise," Dudgeon tells the Brisbane Times.
An eagle ray and boa constrictor are the only known vertebrates to have completed the same feat, which experts now acknowledge could occur more often than they realize. (Read about a snake's virgin birth.)
