Shark conceived without male contact

Genetic analysis of a bonnethead shark pup has revealed the first example of a virgin birth in the shark world (see a video here as well). The female baby - which died from a stingray bite just hours after being born - did not contain a single strand of male genetic material. Instead, she had inherited all of her genes from her mother.

Her aquarium birth stunned scientists who had thought that, like humans, sharks always required a sperm and an egg to become pregnant. Now, it seems that when starved of male attention, female sharks are capable of activating an ancient survival mechanism that allows them to reproduce without any sexual contact. In this particular case, the pup's mother had had not been near another male bonnethead shark for at least three years.

Analysis of the baby shark's DNA has shown it reproduced by parthenogenesis - a process in which eggs develop into embryos without being fertilized by sperm. Although such virgin births are common in the insect world, and have been known to occur among lizards and some snakes, fish and birds, they had never been documented among sharks.