MUSEUM CAMPUS — The rockhopper penguin chick born at the Shedd Aquarium is a girl, aquarium staff announced Monday at a reception featuring a penguin-shaped cake with pink frosting.
There are no observable differences between male and female penguin anatomy, so Shedd staff had to wait for DNA test results to correctly sex young penguins like the rockhopper chick, temporarily known as "No. 22."
Baby chicks are born only with down feathers, which resemble fur, Shedd's website says. They must wait until waterproof feathers grow in before they can go into the water.
When she hatched, the penguin chick weighed 75 grams. At her most recent check-up, the chick weighed in at 4.9 pounds, now sporting adult feathers that allow her to swim freely with the other penguins in Shedd's Polar Play Zone.
The rockhopper chick's birth last June was the latest success in the aquarium's penguin breeding program, which started in 1991 to help repopulate dwindling endangered species.
Rockhoppers are currently listed as "vulnerable" by the International Union for the Conservation of Nature due to disease and warming ocean temperatures.
During the first week in April, Shedd Aquarium members will have an opportunity to vote on the penguin's name. A members-only link will be emailed out next week and the survey will be open from April 5 to 11, a Shedd spokeswoman said.