CHICAGO (WLS) -- Four Magellanic penguin chicks at the Shedd have reached an important milestone: their first swim!
The chicks recently traded their fluffy feathers for waterproof ones, so they left the nest and tested out the water.
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While penguins don't get airborne, they do fly through the water by flapping their strong, solid wings.
Besides their first swim, the Shedd said the penguins have also reached additional developmental milestones, including eating fish, socializing and exploring new spaces around the aquarium.
The sex of the birds is still undetermined, since their reproductive organs are internal. Once samples are taken from inside the chicks' eggshells to help scientists determine their sex, Shedd said it will share any potential naming plans.
While the chicks aren't viewable to the public yet, Shedd visitors can visit the rest of the penguin colony or even come face-to-face with the birds through a virtual or on-site penguin encounter.