On 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 sharks—and both were female. The two swell sharks have been in a female-only habitat at the Shreveport Aquarium for more than three years.

A small shark swimming around a Louisiana aquarium holds a mystery in its DNA. Yoko the swell shark hatched from an egg that was discovered in a puzzling place — an all-female tank, the Shreveport Aquarium announced. “It really proves that life ... uh ... finds a way,” curator Greg Barrick said in a Jan. 24 news release.