How did a female hammerhead shark give birth to a baby shark without mating with a male shark?
In 2001, a hammerhead shark gave birth to a baby shark at the Henry Doorly Zoo in Nebraska. Scientists found it perplexing that the female shark lived in a tank with three other female sharks, and it gave birth to a baby shark without mating with a male shark.
Some scientists believe one reason for this phenomenon is that female sharks can store sperm from male sharks for fertilization, while other scientists believe that sharks can reproduce asexually through rare methods without sperm directly producing offspring.
In 2007, scientists finally solved the mystery through DNA testing. The baby shark had no father. It was the first discovered shark to reproduce asexually.
In 2008, scientists at the Virginia Aquarium & Marine Science Center verified a second shark asexual reproduction case, where a 5-foot-long, 94-pound Atlantic blackfin shark died from unknown complications, and during autopsy, aquarium staff were surprised to find a 10-inch baby shark inside its abdomen.
DNA tests showed that the baby shark embryo did not carry genes from a male shark.
