Shark Virgin Birth? Pup Hatches Despite Mom Having No Contact With Male

BROOKFIELD, IL — The Brookfield Zoo recently welcomed an epaulette shark pup, but the circumstances that led to the young animal's hatching were a bit unusual: The pup's mother had not been housed with a male in four years.

The baby shark hatched Aug. 23, the zoo announced last week. The pup’s mother arrived at Brookfield in 2019 when she was 3, four years shy of sexual maturity. Zoo staff believe she produced a fertile egg independently, without male fertilization, in a process called parthenogenesis, in which an embryo develops from an unfertilized egg cell.

“Parthenogenesis is a natural occurrence in some invertebrates, but less so in complex vertebrates, including sharks,” the zoo said in a news release. “It is believed this is the second Association of Zoos and Aquariums’ accredited facility to report a potential epaulette shark pup produced by an asexual reproduction.”

The first such case of apparent parthenogenesis was at the New England Aquarium, where the pup’s mother originated.

“Our colleagues at New England Aquarium have been a great resource as shark pups produced parthenogenetically can be very delicate,” said Mike Masellis, a lead animal care specialist at Brookfield, in the news release.

The egg incubated for five months before hatching the pup, who is now roughly two months old, about 6 inches long, and visible at the zoo’s Living Coast exhibit. The young shark may eventually grow to be up to 3 feet.