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.

According to the aquarium, the shark egg was first spotted eight months ago. The shark hatched a few weeks ago and the team at the aquarium is working to determine how it was conceived. Once the shark is big enough for a blood draw,

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

A swell shark hatched but had no male present in its habitat. The aquarium’s team noticed the egg eight months ago, and it has been closely monitored. On January 3, the egg successfully hatched. The team determined two female sharks were in the tank and had no contact with a male in over three years.