However, when there are no males around, asexual reproduction, despite its shortcomings, is the best option for species survival.ĭudgeon described asexual reproduction as a 'holding-on mechanism,' passed down along generations of women until male partners are available. This process causes 'extreme inbreeding,' she said, and is not conducive to adaptability, or generational longevity and diversity.

©Shedd Aquarium/Brenna Hernandez Asexual reproduction is common for animals like starfish, deep-sea worms, and stick insects, but among vertebrates, it’s a rarity. Switching from sexual to asexual reproduction is far less common, although not impossible, Dudgeon told The New Scientist, citing an eagle ray and boa constrictor who have done so.Īsexual reproduction in sharks happens when a polar body, or the cell adjacent to the egg fertilizes it, said Dudgeon. DecemScience Virgin birth in aquarium sharkseven when potential mates are nearby One of the Shedd Aquarium zebra sharks.

However, among those who have done so, the females were virgins. Some species of sharks, snakes, turkeys, rays, and Komodo dragons have been able to reproduce without males. Hence, asexual reproduction may have been more likely.Īsexual reproduction isn't as uncommon as it may seem. Most commonly found in plants and invertebrate organisms, an increasing number of vertebrate species have recently been reported employing this reproductive strategy. One possibility was that Leonie stored sperm from her former partner and user it four years later, but that was quickly discredited since the three offspring only have their mother's DNA, according to Christine Dudgeon, a research officer in biomedical sciences at the University of Queensland. Parthenogenesis is a natural form of asexual reproduction in which embryos develop in the absence of fertilisation. It's believed that asexual reproduction is more likely to happen in a tank where there are only females, and Aqua World Oarai's zebra shark is the third case of parthenogenesis in the world that occurred for a fish kept in the same tank as a male.So the question is, how did she conceive three more offspring on her own? Dr Christine Dudgeon of UQs School of Biomedical Sciences, who documented the change at Townsvilles Reef HQ Aquarium, said sharks could reproduce without a mating partner, but none with a. Tokunaga says parthenogenesis can occur in sharks when small cells known as 'polar bodies' produced during meiosis of the base cells for the egg play the role of sperm. A DNA test confirmed that the baby shark was produced through parthenogenesis. While eggs that are produced via parthenogenesis are less likely to hatch compared to those that go through a regular breeding process, the aquarium successfully hatched the egg by maintaining the water temperature at 26-27 degrees Celsius while adding fresh, cold seawater. Unable to confirm mating between the two, the aquarium suspected that it could be a case of asexual reproduction. The black-and-white striped pattern unique to young zebra sharks is only visible for about a year, and it's expected to change to a brown-dotted pattern as the fish grows.Īccording to Kotaro Tokunaga, who is in charge of the sharks at the facility, the female zebra shark laid an egg in the fall of 2022 while being kept with a male fish. It has been on display as part of the fifth-floor exhibition at the aquarium since March 4. An adult zebra shark with a leopard pattern. In sharks, asexual reproduction usually happens via a process called 'automictic parthenogenesis,' explained Feldheim.

Zebra shark asexual reproduction