Shark reproduces without mate A female zebra shark

Shark reproduces without mate

A female zebra shark in an Australian aquarium has produced live offspring asexually, three years after being separated from her longterm mate. The shark, named Leonie, hatched three eggs in April last year, despite being kept apart from male sharks since 2013. The breakthrough research, now published in Scientific Reports. While scientists have previously observed similar births in vertebrates like sharks, rays and reptiles, this is the first time a female shark has ever been observed reproducing asexually after previously mating with a male. Some scientists think the reason for a birth like this might be nature’s reproductive strategy to aid survival during periods of isolation. In other words, switching to asexual reproduction could be a useful strategy to allow a population to hold on in extreme isolation. It is only the third documented case of a vertebrate of any species switching its reproductive strategy from sexual to asexual. An eagle ray and a boa constrictor, both held in captivity, are the only other species known to have undergone this unusual biological shift. The process is called parthenogenesis. Zebra sharks laying eggs without a male present is not unusual. For this type of shark, it's much like a chicken -- they lay eggs whether they are fertilized or not. However, this time, three of Leonie's eggs emerged into live hatchlings. There a couple of possible explanations for Leonie's eggs reproducing, but the best explanation thus far is through asexual means.

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