RACINE, Wis. —Two African penguin chicks hatched at the Racine Zoo in mid-January, becoming the first of their endangered species born there in 10 years.

The first chick broke from its shell on Jan. 14. A second hatched on Jan. 17. Each weighed a mere 2 ounces.

Neither of the chicks have been named. Their genders have yet to be determined. Zoo staff will find out via blood tests after several months.

It's difficult for one penguin couple to take care of two offspring. So, while one of the babies is cared for by its biological parents, mother Robben and father Linus, the other is watched over by a surrogate couple, mother Blue-Yellow and father Blue-Green.

The births are a groundbreaking event for the Racine Zoo, according to Beth Heidorn, the zoo's executive director.
“This is an important victory for the African penguin breeding program we’ve been working so hard at cultivating,” said Heidorn.
In the wild, there are about 52,000 African penguins. Habitat loss, oil spills, pollution, and commercial over-fishing threaten their survival.

Watch Linus feed one of the chicks in the video below: