A shark at the Virginia Aquarium & Marine Science Center in Virginia Beach produced a baby without a male shark. The Friday issue of the Journal of Fish Biology reported that a female blacktip shark named Tidbit had not been in contact with male sharks for at least eight years and yet experienced what the scientist call a "virgin birth." She delivered a single pup. Moreover Tidbit had been captured too young to have mated in the wild.

Scientists refer to the phenomenon as "parthenogenesis." They also added that that many female sharks may have the ability to reproduce without actual mating. This is an ability of female reptiles, birds and more recently discovered in vertebrates such as Komodo dragons. What happens is that the mother’s chromosomes split during egg development and pair with a copy of them.

But unlike birds or reptiles that carry two types of sex chromosomes, in sharks the resulting embryo will always be female because the mother only has X chromosomes to contribute. So as far as diversity is concerned, this is unlikely to be a fortunate reproduction method.

"There was absolutely no genetic material from a father," said lead author Demian Chapman of the Institute for Ocean Conservation Science at Stony Brook University in New York. "Every part of this fingerprint from the baby was a match for Tidbit."
The unborn pup was discovered during a necropsy on Tidbit. She had been sedated for a routine vet exam in May 2007 but did not respond well. The shark died a short time later.