![]() “One reason why we haven’t seen it before could be because we haven’t been looking for it,” says Dudgeon. In recent years, however, scientists have been seeing it more often – not because it’s a growing trend but simply because the switch between sexual to asexual reproduction hadn’t been studied, as was the case with Leonie. ![]() Though asexual reproduction is a widely used method of producing offspring (for example, it’s how bacteria, many species of worms and insects, plants, and jellyfish all reproduce), the process is rare for vertebrates. “What we want to know now is, could this occur in the wild, and, if so, how often does it?” “Leonie adapted to her circumstances, and we believe she switched because she lost her mate,” Dudgeon said. Why Leonie chose to ‘go it alone’ is not clear, although researchers say that it likely comes down to adaptation. Zebra sharks have been known to reproduce parthenogenetically, as was observed in 2011 at the Dubai aquarium, but in that case the animal had had no history of sexual reproduction. Zebra sharks reach maturity at around seven years of age and can live to over 35 years of age in captivity. Confusingly, in Australia the zebra shark is called the leopard shark yet it’s a different species from the leopard shark found off much of the west coast of North America (though not as far north as Canada). “We thought she could be storing sperm but when we tested the pups and the possible parent sharks using DNA fingerprinting, we found they only had cells from Leonie,” said University of Queensland biologist Christine Dudgeon, co-author of the study, in a statement.įound in the warm waters of the Indo-Pacific region, the zebra shark is naturally a bottom-dweller, with a blunt nose and cylindrical body. Not so for Leonie, who had already had pups with a male zebra shark up until 2013, thereby making this the first documented case of a shark switching from sexual to asexual reproduction. 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.As reported in a new paper published in the journal Scientific Reports, at the Reef HQ Aquarium in Townsville, Australia, a zebra shark named Leonie hatched three eggs despite having no access to a mating partner for the last three mating seasons.Īlthough previous cases have been noted of sharks reproducing asexually, through a process known as parthenogenesis, those were instances where the female shark had no exposure to males during their whole reproductive lifetime. But it was Leonie’s switch from sexual to asexual reproduction that was a “really big surprise,” Dudgeon tells the Brisbane Times. One of Leonie’s offspring who’d never reproduced sexually also produced hatchlings using eggs fertilized by a cell known as a polar body. In essence, she made the offspring all on her own, marking the first time a switch from sexual to asexual has been witnessed among sharks!Ī sexual reproduction itself is not so unusual when males are scarce, it lets species from snakes to turkeys survive until mates can be found, though it “reduces genetic diversity and adaptability” and leads to “extreme inbreeding,” says study author Christine Dudgeon. ![]() Scientists checked and her hatchlings contained DNA from Leonie only. Zebra Shark Makes News by Producing Her Own Babies!Ī zebra shark named Leonie surprised scientists in Australia when she gave birth to offspring without the help of a mate! ![]()
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