A blacktip shark at a Virginia aquarium got pregnant despite not having been around a male of her kind for a decade, the Virginian-Pilot reports. Scientists have long suspected that sharks, like some smaller vertebrates, could reproduce asexually but this is only the second confirmed case. Tests showed the baby shark had genetic material purely from its mother.
Nobody is sure what triggers asexual reproduction—known as parthenogenesis—in female sharks, but experts suspect it may be a shortage of males. It is unlikely to help dwindling shark populations, scientists say, as the lack of genetic diversity is equivalent to the result of many generations of inbreeding. "It's kind of a crapshoot, last-ditch way to reproduce," said one of the researchers, whose findings appear in the Journal of Fish Biology.