In an unusual turn of events, a baby swell shark named Yoko was born at the Shreveport Aquarium in Louisiana. The shark was born in a tank that had not seen a male shark for over three years.

Yoko the swell shark was born in a habitat of all-female sharks who hadn't seen a male in years. The aquarium has two possible explanations — and hopes to get confirmation in the coming months.

The pup hatched in a tank housing two female sharks who hadn't been around any male sharks in over three years.

Surprised faces at the Shreveport Aquarium in the U.S. state of Louisiana because baby swift shark Yoko got born there in an aquarium with only females. Yoko was born in early January after crawling out of an egg in an aquarium with two female sharks.