A female shark gave birth to a pup at the Brookfield Zoo in Illinois this year – despite the baby having no father. The female epaulette shark was never housed with a male shark, but produced a fertile egg without the need for a male, the zoo said in a news release.
The child was born in August to the 3-year-old mother, although epaulette sharks usually become sexually mature at age 7. The process of developing an embryo without a fertilized egg cell is called parthenogenesis.
Parthenogenesis, which means “virgin creation” in Greek, occurs mainly in some jawed vertebrates, but is unnatural to mammals, according to National Institutes of Health. It can occur in whiptail lizards, Komodo dragons, hooded sharks and other animals, according to Science.org.
According to the zoo, parthenogenesis is less common in sharks, which are complex vertebrates, meaning they have backbones.
Still, this phenomenon is not completely unheard of in epaulette sharks – this is believed to be just the second case at a facility accredited by the Association of Zoos and Aquariums. Brookfield Zoo’s female adult epaulette sharks originate from the New England Aquarium, where the first case of parthenogenesis was recorded.
The mother, who arrived at the zoo in 2019, began laying eggs in 2022, but they were typically non-viable – until one came out fertile.
After incubating the egg for five months, the puppy hatched. It is now five to six inches long and is expected to reach about three feet when fully grown.
“We are pleased to report that our epaulette pup has been eating well on his diet of minced capelin, chopped squid tentacles and other finely chopped seafood. Our colleagues at the New England Aquarium have been a great resource as parthenogenetically produced shark pups , can be very delicate,” Mike Masellis, a lead animal care specialist at Brookfield Zoo, said in a statement. “We are looking forward to the guests seeing the puppy.”
Epaulette sharks are known to appear to “walk” on the ocean floor, the zoo says. The nocturnal fish are native to the waters between New Guinea and Australia and live in shallow areas near the sandy bottom.
They are called epaulettes — meaning decorative — because a pair of false eyes on the back of the head look like decorations on a uniform, according to the zoo.