Excerpt from All About Sharks: A Complete Guide to the World’s Most Misunderstood Predator (Nov. 2017):
Virgin birth? No big deal, at least for some sharks and other animals with certain superpowers.
In 2001, a female hammerhead in Omaha gave birth to a pup despite not being around male hammerheads in at least three years.
Though interspecies mating is very rare, it’s possible.
However, testing the DNA of the pup proved the pup to be 100 percent hammerhead.
Researchers determined they had just witnessed automictic parthenogenesis which happens when female sharks are isolated from males for a prolonged period of time and an unfertilized egg within the mother merges with another egg (a “sister polar body”) and a fetus is formed.
This highly unusual act only happens in isolated situations as a last resort to keep the species alive because the pup only has genetic material from one parent, not two.
That lack of genetic diversity would eventually kill off the species if continued, so automictic parthenogenesis happens is rarely documented.
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