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. Last Updated: 07/27/2016

Female Shark Reproduces Without Male DNA

A hammerhead shark that gave birth in a Nebraska aquarium reproduced without mating, a genetic analysis shows.

This form of asexual reproduction, called parthenogenesis, has been found in other vertebrate species, including some snakes and lizards. But this is the first time it has been documented in a shark.

Researchers from the Guy Harvey Research Institute at Nova Southeastern University in Florida and Queen's University Belfast in Northern Ireland found no male DNA in the female baby shark, which was born in December 2001 and died shortly after birth, apparently killed by another fish.

The mother was one of three female bonnet heads, a small hammerhead species, that had been captured in Florida and kept without male sharks for three years in the Henry Doorly Zoo in Omaha.

At the time of the birth, many scientists thought that the female had mated with another species, or that it had used sperm obtained years before. Female sharks are capable of storing sperm.

But through analysis "it was pretty clear that there was no male contribution," said Mahmood Shivji, director of the Guy Harvey Research Institute. "These guys have proven their case," Hueter said of the researchers.

Shivji said that after the shark's birth was reported, keepers at the Belle Isle Aquarium in Detroit reported similar virgin births by white spotted bamboo sharks. While those births have not been proved to result from parthenogenesis, Shivji said, it is reasonable to assume they did.

"It's a last-resort tactic that animals use when they absolutely can't find another mate," Hueter said.

But sharks have plenty of other problems that are of potentially greater impact. "I would be concerned about a lot of other things than whether or not a female shark can get a date for an evening," he said.