The second shark-reproduction mystery in as many months (read about the May virgin shark birth here) has surfaced at a U.S. aquarium—this time, at the Virginia Aquarium and Marine Science Center. According to an Associated Press report, the aquarium’s veterinarian Bob George observed that there might have been “hanky-panky” in the shark tank.

During an autopsy of a deceased female blacktip reef shark named Tidbit, George found a 10-inch-long shark pup poised for birth. But with no male blacktips listed on the aquarium’s roster, George was clueless as to the baby-daddy’s identity. DNA samples of both Tidbit and her fetus were sent to one of the co-authors of last month’s purported parthenogenesis occurrence in Omaha, NE. Researchers hope to learn whether the pup was a rare hybrid of two similar species (an event never before seen in captive sharks), or another instance of asexual reproduction.

Genetic tests will reveal how the chromosomes line up, but until then, George has his eye on one of Tidbit’s tankmates—a sandbar shark. Apparently, this species is known for jawing it up with the ladies and then high-tailing it to the nearest sandbar when it’s time to assume a more proactive parental role. —Dave Prochnow