It lets a female produce young even when there are no males around. This unusual strategy can sometimes make sense, biologists argue. And this type of reproduction has occurred before in at least three types of sharks: the bonnethead, blacktip and whitespotted bamboo species. This is called parthenogenesis (PAR-then-oh-JEN-eh-sis). The females of certain animals sometimes can produce offspring from an unfertilized egg. So the researchers puzzled over how this shark pup came to be.Ĭould the ray have been the pup’s dad? The scientists rejected that idea pretty quickly: The two species are so distantly related that it should have been nearly impossible for them to mate and produce live offspring. Eleven months later, two of those egg cases showed signs of a live, developing shark inside. (Rays are members of the shark family and resemble flattened sharks with wings.) In January 2011, the brownbanded bamboo sharks laid egg cases - nicknamed mermaid’s purses. There, they shared a tank with female blacktip reef sharks and a male Javanese cownose ray. When new facilities at San Francisco’s Golden Gate Park opened up, the three females moved in. At the Long Beach facility they had shared a tank with male brownbanded bamboo sharks.Īfter leaving Long Beach, the female sharks spent a year in a temporary home. They came from an aquarium in Long Beach, Calif. The Steinhart Aquarium got the tank’s three female sharks in September 2007.
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