‘Waddle it be’ — a young female penguin

BY HANNAH LUTZ March 24, 2014

The Shedd Aquarium hosted a “waddle it be?” party to announce whether its youngest penguin is male or female. 

With a show of hands, most aquarium visitors voted Friday that the bird was female. And Shedd Aquarium manager Lana Vanagasem sliced open a penguin-frosted cake to reveal a pink center — meaning the majority was right. “We were really happy to find out Rockhopper 22 [the penguin] was a female,” Vanagasem said. 

Females make up 70 percent of the penguin collection but males rank higher among the rockhopper penguins, according to Shedd Aquarium spokeswoman Nicole Minadeo. Ninety chicks have hatched at the aquarium over the last 20 years. 

On Friday, Rockhopper 22 stood on a rock in the center of the penguin zone, its rockhopper distinguishing yellow feathers beginning to grow around the eyes. The aquarium staff currently refers to the penguin as Rockhopper 22, but this April aquarium members will have the opportunity to help choose her name.

The healthy, five pound penguin was born June 12, 2013, and three months later, she was fully grown and out of the nest, according to Dr. Caryn Poll, senior staff veterinarian. 

Since there is no visible feature to determine penguins’ gender, the Shedd Aquarium sent Rockhopper 22’s blood sample for DNA testing.

Birds have Z and W chromosomes, Poll said. Females, like Rockhopper 22, have a ZW combination, and males have a ZZ combination, which means female birds determine gender, Poll added.

Although penguins are usually monogamous, that wasn’t the case with Rockhopper 22’s parents, Rockhopper 51 and 53, according to Vanagasem. Sometimes penguins will switch mates, Vanagasem said. “It’s a little bit of a soap opera every season to see who will end up with who,” she said.

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Shedd Aquarium visitors learned Monday that the new penguin was a female.