A gay penguin couple has welcomed their first chick together after forming a bond during the breeding season.
Elmer and Lima, two adult male Humboldt penguins, at Rosamond Gifford Zoo in Syracuse, New York, welcomed their chick on January 1.
The pair grew close together during the breeding season and cared for the egg together, the zoo said.
Elmer was hatched at the zoo in 2016, and Lima in 2019.
They are the zoo's first same-sex foster couple and are part of a colony of 28 penguins.
The zoo has relied on foster penguin parents to incubate eggs in the past and there have been previous tragedies of breeding pairs of penguins unintentionally breaking their fertilized eggs.
Zookeepers have resorted to swapping the real egg for a dummy and giving it to another pair to incubate.
Last year, Opal was hatched when first-time foster parents Luis and Calypso incubated her egg and cared for her after her biological parents Juan and Rosalita broke an egg.
Elmer and Lima paired up last fall, built a nest and defended their territories.
The team that cares for the penguins decided to test their fostering abilities.
Zoo Director Ted Fox said: "Some pairs, when given a dummy egg, will sit on the nest but leave the egg to the side and not incubate it correctly, or they’ll fight for who is going to sit on it when.
“That’s how we evaluate who will be good foster parents, and Elmer and Lima were exemplary in every aspect of egg care.”
On December 23, Poquita laid an egg with her mate Venta, and the team swapped it for a dummy.
The egg was given to Emler and Lima. The pair took turns incubating the egg until it hatched and have been keeping it warm and feeding it ever since.
Mr Fox said: "At our first health check when the chick was five days old, it weighed 226 grams (8 ounces).
“It continues to be brooded and cared for by both Elmer and Lima, who are doing a great job. And once they have experience doing this and continue to do it well, they will be considered to foster future eggs.”
Fox added: "Elmer and Lima’s success at fostering is one more story that our zoo can share to help people of all ages and backgrounds relate to animals."
Humboldt penguins are native to the Humboldt current off the coast of Chile and Peru in South America.
They are considered vulnerable as the wild population is declining due to habitat loss and climate change.