Adult brownbanded bamboo shark can hold sperms for nearly four years before giving birth to her kids, says biologist from the California Academy of Sciences. Researchers got surprised when adult female sharks at Steinhart Aquarium were kept in isolation from male sharks for 45 months; still they produced kids.
“Long-term sperm storage – where a female can delay fertilisation for months or even years after mating – is a remarkable adaptation that helps promote genetic diversity,” said Luiz Rocha, curator at ichthyology department of California Academy of Sciences.
This is the first time that bamboo sharks have been documented of storing sperms for such a long period of time. According to researchers, sharks can store sperm in the tubules near their oviduct, a reproductive area that helps produce the jelly-like substance surrounding fertilised shark eggs.
There are chances that pup shark might have born through process called parthenogenesis, in which a female is able to produce kids on her (asexually) own without an intervention of any male. To confirm it, biologists examined the pup’s DNA and were shocked to found that pup wasn’t born asexually but was half clone of his mother and had two parents.
Now researchers are confronting with a big question that when and how sharks choose an alternative of reproduction. “We know that several species of sharks have reproductive tricks like storing sperm or reproducing by ‘parthenogenesis’ in the absence of males, but we need to know when and how these alternate techniques are triggered,” said Moises A. Bernal, a researcher in the academy’s ichthyology department.
Moreover, many researchers were glad to see different ways of making clones in wildlife. Apparently it is a boon to wildlife population especially for those endangered species and shark is one of them.