Two baby penguins spent Monday and Tuesday busily pecking their way out of their eggs at the Shedd Aquarium, becoming the first two captive animals to be bred and born in its vast Oceanarium, opened in 1991.
The 3-ounce chicks were from eggs laid two months ago by the Oceanarium’s breeding pairs of rock hopper penguins. After 24 hours of breaking through its shell, one had fully emerged by Tuesday morning. The second should be out fully Wednesday.
They were hatched in an incubator by Shedd keepers, who took the eggs from their parents, substituting dummy eggs so that the adults would have something to sit on.
The births bring the Oceanarium’s penguin population to 13 rock hoppers, 18 gentoo penguins and four magellanic penguins. When the two chicks grow big enough toward the end of the summer, they will join all the others in the Oceanarium’s lower-level penguin habitat.
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All three species live in noisy harmony in a habitat that re-creates the coastline of the Falkland Islands, a group of South Atlantic islands off the east coast of Argentina. The air temperature in their glassed-in habitat remains a chilly 38 degrees, and the water in their 60,000-gallon pool is a constant 48 degrees.
Captive penguin births are not unusual, though they are difficult to engineer. Penguins breed once a year, in the springtime, when the earlier sunrise triggers their biological clocks, putting them into a mating frame of mind.
“We simulate the changing seasons with computer-controlled lighting, which mimics the lengthening and shortening days in the Falkland Islands,” said the head keeper of the penguins, Mark Ryan.
To human eyes, penguins are indistinguishable, perfect clones of each other. Ryan said even keepers cannot tell individuals from one another, nor can they differentiate the sexes, though penguins apparently have no problem sorting out those details among themselves.
The Shedd’s 11 adult rock hoppers have been at the Oceanarium since before it opened, arriving as sexually immature youngsters. When they reached sexual maturity two years ago, they began pairing off.
Last year they laid their first six eggs, all of them infertile. This year there were six more rock hopper eggs, including the two fertile ones.
“The first time penguins lay an egg,” Ryan said, “they don’t know bwhat it is, so they don’t incubate it properly. We’ve been pulling the eggs and giving them fake eggs to practice with. Next year, we’ll let them sit on their own.”
Both mother and father penguins take an active role in parenting, sitting on the eggs during 65-day incubation period. They also warm the chicks and feed them from their own regurgitated food during the two months it takes the chicks to develop their own insulation, allowing them to live independently.
The new chicks are being fed tiny filet strips of herring dipped into a blenderized “milk shake” of fish, krill and vitamins.
The Oceanarium’s next expected baby is the August birth of a Pacific white-sided dolphin.