Charlotte the stingray at the Aquarium and Shark Lab by Team Ecco in Hendersonville, North Carolina is expecting pups any day—the only problem is they have no idea how she became pregnant. Staff say when Charlotte started to swell in September they feared she had cancer. However, after a closer examination it was discovered that she was in fact pregnant. It left staff very confused. “We have no male ray,” Team Ecco wrote. There are two possible explanations. The first is a very rare process called parthenogenesis, in which the eggs develop on their own without fertilization and create a clone of the mother. The second is that Charlotte could have reproduced with one of two young sharks that were added to the tank in July. Once the pups are born they will conduct DNA testing on them to determine if they are a mixed breed or are clones of their mother.