A baby Gentoo penguin is weighed at the Pittsburgh Zoo & PPG Aquarium in Highland Park on Thursday, July 14, 2016. The zoo had four Gentoo penguin babies this year to three sets of parents. The oldest was born on May 31, with the youngest born on June 12 & 14.

 Penguin keepers Katy Wozniak, 39, of Gisonia, (left) and Jessica Ries, 25, of Munhall, right, hold two of the baby Gentoo penguins before checking their weights.

 Two sibling baby Gentoo penguins sit together in their nest.

 A baby Gentoo penguin sits in the nursery at the Pittsburgh Zoo & PPG Aquarium. With an estimate of 387,000 breeding pairs worldwide, Gentoo penguins have been given a near threatened status on the International Union for Conservation of Nature's Red List.

 Gentoo penguins stand in the exhibit at the Pittsburgh Zoo & PPG Aquarium. The zoo's newborn Gentoo penguins still have some time until they fledge and are able to join the rest of the penguins in the exhibit.

Keeper Katy Wozniak, 39, of Gisonia, clean out the nursery where baby Gentoo penguins sit on their nests at the zoo.