‘Jesus shark’ born without male-fertilized egg gains national attention
Nov 9, 2023, 2:38 PM
(Photo: Jim Schulz/CZS-Brookfield Zoo)
The Brookfield Zoo in Chicago announced an epaulette shark successfully hatched in August despite its mother not being housed with a male since arriving at the zoo in 2019.
“At that time, she was only three years old, and the species reaches sexual maturity around seven years of age,” Sondra Katzen of Brookfield Zoo’s public relations team relayed in a press release.
The epaulette shark grows to about 3 feet long and has paddle-shaped fins that it uses to walk on the ocean floor and on dry land.
Under these circumstances, animal care staff at the zoo believe the female produced a fertile egg without needing to be fertilized by a male’s genetic material — through a process called parthenogenesis where an embryo develops from an unfertilized egg cell out of her own genetic material.
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“Have you heard this online, people are calling this Jesus shark?” Jake Skorheim, the host of KIRO Nights, asked Mike Masellis, a lead animal care specialist at Brookfield Zoo.
“I have heard that. I mean, it is definitely a remarkable animal,” Masellis answered. “And it’s remarkable, especially for animals with backbones to exhibit parthenogenesis. A lot of invertebrates and plants and things can reproduce in that way, but it’s not common for animals that are more closely related to us.”
The pup is now two months old and approximately five to six inches in length. Epaulette sharks are mostly nocturnal creatures found in warm, relatively shallow waters over sandy bottoms from the southern coast of New Guinea to the northern coast of Australia.
“As far as we know, this is the eleventh epaulette shark born via parthenogenesis,” Masellis added. “10 or so at the New England Aquarium, and then No. 11 here at the Brookfield Zoo.”
Shark pups are independent from their mothers from birth. Once the mother shark lays the egg and provides a little bit of energy for some initial growth within the egg, pups are on their own. Pups eat all kinds of small things like small crustaceans on the ocean floor.
“Same at the zoo, they’ll get shrimp and various invertebrates along with finely chopped fish will usually put a bit of vitamins in their food just to ensure that they have a well-rounded diet,” Masellis said.
While the zoo has yet to decide on a name, Masellis stated the zoo staff is already leaning towards the name “11.” While the shark’s birth remains a mystery, Brookfield Zoo hopes more answers can be discovered as the shark grows older.
“These are the types of questions that we hopefully can answer once our pup is a little bit bigger,” Masellis said. “We can get some genetic material from the animal and kind of test it just to confirm it.”
The baby shark can be seen in one of the habitats inside the zoo’s Living Coast section.
“We’ve gotten a huge response online, which has been great to see that people can get excited about sharks because they’re not as traditionally cute as a lot of the other animals that you might see at a zoo or aquarium,” Masellis added. “So whenever people get excited about fishes, we’re always happy about it.”
- Tune in to KIRO Newsradio weekdays at 7 pm for KIRO Nights with Jack Stine.