A 600-pound killer lurks, striking returning mother penguins with food for their chicks. Desperate to provide for her Rockaroni chicks, a Rockhopper penguin squares up against the Sea Lion, but will she emerge unscathed? Secrets of the Penguins is now streaming on @disneyplus and @hulu https://on.natgeo.com/4cHzyFv Explore the World with National Geographic subscriptions: http://natgeo.com/ytngmagazine ➡ Subscribe: http://bit.ly/NatGeoSubscribe And check out more National Geographic series and