The Rosamond Gifford Zoo in Syracuse says the same-sex foster couple, Elmer and Lima, are a first for the zoo, although several other institutions have seen success with same-sex penguins tending eggs together and caring for newborns.
Zoo officials said on Friday that Elmer and Lima watched over an egg that came from a pair of breeding penguins that have a history of inadvertently breaking their fertilised eggs. They were successful, and the chick hatched on New Year's Day.
Experts had tested the duo first by putting a dummy egg in a nest the pair built together last year during the current breeding season.
Zoo director Ted Fox said not all penguin duos were good at incubating eggs, but "Elmer and Lima were exemplary in every aspect of egg care."
After the pair passed the test, officials removed the dummy egg and replaced it with a real one. The duo took turns incubating the egg until the chick hatched, Fox said.
"It continues to be brooded and cared for by both Elmer and Lima, who are doing a great job," Fox said. "And once they have experience doing this and continue to do it well, they will be considered to foster future eggs."
Native to the Pacific coast of South America, Humboldt penguins are listed as vulnerable, according to the International Union for Conservation of Nature.
AAP with The Project