Students at Carl Hayden Community High School were stunned when a baby shark appeared in one of their fish tanks.
More amazing was that the mother shark had been in the tank alone for nearly four years.
How did it happen?
This type of birth is known as parthenogenesis, in which an unfertilized egg develops into a new pup, said Lajvardi, program manager for the Carl Hayden Center for Marine Science.
"The mother’s gene divides in half and recombines with its own collection of genes to create a new individual," Lajvardi said. "Normally, it would recombine with the father’s half of the gene. But because there is no father, the mother provided the other half."