Shreveport Aquarium experts take care of the new swell shark pup. Screenshot of a Shreveport Aquarium video, edited to include arrowOn January 3, the Shreveport Aquarium in Louisiana welcomed a swell shark pup into the world under mysterious circumstances: It was born in a tank that housed only two sharksand both were female.The two swell sharks have been in a female-only habitat at the Shreveport Aquarium for more than three years. So, how did this birth happen?This situation is incredible and shows the resilience of this species, Greg Barrick, the aquariums curator of live animals, says in a statement. It really proves that life... uh... finds a way, he adds, referencing Jurassic Parks surprisingly similar situation with female dinosaurs.Aquarists have two potential explanations for what process created this shark. One of the two adult females might have carried out a rare form of asexual reproduction called parthenogenesis, or it could be a case of delayed fertilization. The team will be able to tell which one it wasand who the mother iswith a DNA analysis, but they have to wait a few months before they can draw blood from the baby.Though Barrick has been referring to the pupnamed Yoko after the Chumash word for shark, onyokoas a she, he admits they cant determine its sex yet, per CBC Radios Sheena Goodyear.If the shark was born through parthenogenesis, it would join a handful of similar known births. In general, we think parthenogenesis is a last ditch effort for a female to pass on its genes, so when a female is isolated from conspecific males, she is able to undergo parthenogenesis, Kevin Feldheim, a lab manager at Chicagos Field Museum, tells NPRs Rachel Treisman. How parthenogenesis kicks in or what cues the females use to begin the process [of self-fertilization] remains to be discovered. He adds that parthenogenesis has only ever been observed once in the wild. The phenomenon has been recorded more frequently in captive animals.Komodos are famous for it, Colin Stevenson, head of education at Crocodiles of the World, an England zoo, tells the Guardians Karen McVeigh. They can reproduce normally, but every now and again, they pop out a parthenogenetic one. The trick is to work out what kicks it off.As for delayed fertilization, many female sharks are able to store sperm in their oviducal glands, preventing it from reaching an egg until long after the shark has had contact with a male. But exactly how long they can do so remains a mystery.Bob Hueter, a shark scientist at the nonprofit Ocearch who is not associated with the Shreveport Aquarium, tells CBC Radio that shark fertilization is sometimes delayed until certain conditions change, such as the weather, food availability or proximity to breeding grounds. The longest-ever shark sperm storage known to scientists was documented in 2015, and it lasted almost four years.The swell sharks at the Shreveport Aquarium, however, were in female-only tanks even before arriving at the facilityat least as far back as 2014, Barrick tells CBC Radio, so if it is delayed fertilization, it is the first of its kind for that length.While Yoko is currently thriving off-exhibit, per the statement, the aquarists are aware that shark pups born from rare reproductive events usually face health issues.Should Yokos time with us be brief, it will still leave an unforgettable legacy, contributing invaluable insights to the study of shark reproduction and conservation efforts, the aquarium writes in the statement.Get the latest stories in your inbox every weekday.Filed Under: Animals, Baby Animals, Fish, Mysteries, Reproduction, Sharks, Weird Animals