A viral video showing a baby zebra shark hatching from its case—sometimes referred to as a "mermaid's purse"—has been viewed over four million times.
The TikTok video, from the San Antonio Aquarium, Texas, shows a handler cutting open the case with a pair of scissors.
"Today we are cutting open, or hatching out, a shark egg," the video narrator says. "But it's not just any shark egg, it's a zebra shark egg."
Zebra sharks are designated an endangered species by the IUCN Red List. Their population is decreasing. The species is found in the Pacific and Indian oceans. They are an inshore species, living on sand, rock reefs and coral bottoms. They hunt at night, generally feeding on mollusks, crustaceans and small bony fish.
For many years zebra sharks were misidentified as two species, as pups are born with black and white stripes, while adults are spotted. Their maximum size is around eight feet and they can live for between 25 and 30 years.
The species is under threat from humans. The species is prized for its meat and is hunted and sold throughout the Philippines, Thailand, Indonesia and Malaysia. Its fins are also used to make shark fin soup, which is considered a delicacy in China.
The Florida Museum says zebra sharks are good at adapting to captivity, making captive breeding programs a big success.
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In the San Antonio Aquarium video, the handler explains why they are helping the baby shark hatch: "This process does not cause any harm to the pup but actually aids it," she said. "Only 30 percent of shark eggs hatch, so sometimes they need a little help and we're more than happy to do just that. Especially in this case where the zebra shark is an endangered species."
Shark reproduction varies among different species. For zebra sharks, the male transfers sperm to the female using claspers—an extension of the pelvic fin analogous to a penis. Females can lay four eggs at a time and these eggs are anchored to the seafloor for six-and-a-half months before they hatch.
In other shark species, females give birth to live young. In some species, such as the sand tiger shark, unborn pups cannibalize one another, with the largest eating all but one of their siblings.
This gestational behavior has been traced back prehistoric species, including the megalodon—the biggest shark to ever live. Research published in 2020 showed live young were born at 6 foot in length. Researchers say they were able to get this large by gobbling up their siblings, which served as a high-protein snack for the growing sharks.
Stock image of a zebra shark. A zebra shark pup was filmed hatching in a video that has gone viral on TikTok.Stock image of a zebra shark. A zebra shark pup was filmed hatching in a video that has gone viral on TikTok.Getty Images
