Scientists have finally discovered how a baby hammerhead shark came to be born at the Henry Doorly Zoo in Nebraska back in 2001. There were only three female sharks in the tank and none of them had had contact with a male in at least three years.
Initially the scientists thought that sharks might have the ability to store sperm. Testing revealed that the baby only had it's mother's DNA, proving that sharks are capable of parthenogenesis, or conception without male fertilisation.
"The findings were really surprising. As far as anyone knew, all sharks reproduced only sexually by a male and female mating – requiring the embryo to get DNA from both parents for full development, just like in mammals," said Dr Paulo Prodohl.