This epaulette shark pup hatched Aug. 23, 2023, at Brookfield Zoo, born from what staff believe was an unfertilized egg. (Jim Schulz / CZS-Brookfield Zoo)

Brookfield Zoo unexpectedly welcomed a new baby epaulette shark in August. 

Unexpected because the pup's mother had never been mated with a male. The pup presumably developed from an unfertilized egg, according to zoo officials.

Such so-called “virgin births” — a process of female asexual reproduction known as parthenogenesis — are common in some organisms including plants, insects, reptiles and more, but less so in complex vertebrates, including sharks.

A zebra shark at Shedd Aquarium reproduced on her own in 2022. 

Spontaneous parthenogenesis occurs when a creature that typically reproduces sexually suddenly goes it alone. The phenomenon is best documented in zoo settings, and scientists have learned it may be an inherited trait: Females that experience parthenogenesis might be more likely to have daughters that can do the same.

In Brookfield’s case, all of its adult female epaulette sharks came from the New England Aquarium, which was the first accredited facility to report an epaulette pup produced asexually.

Pups born via “virgin birth” tend to have a short life expectancy due to rare recessive genetic conditions. Brookfield staff have been closely monitoring the now two-month-old pup behind the scenes and have been consulting with the New England Aquarium regarding care of the shark.

“We are happy to report that our epaulette pup has been eating well on her diet of finely chopped capelin (fish), minced squid tentacles, and other finely chopped seafood. 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 Zoo. “We are looking forward to guests being able to see the pup.”

Epaulette sharks, regardless of the circumstance of their birth, are already an intriguing species: They’re one of nine species of “walking shark.”

In this video provided by Brookfield Zoo, you can see the pup “walk” across the aquarium using its strong pectoral fins. Epaulettes have even been known to walk on land.   

Contact Patty Wetli: @pattywetli | (773) 509-5623 |  [email protected]