The Rosamond Gifford Zoo in Syracuse, N.Y., is celebrating the fostering of a chick by a pair of male penguins who are raising the chick together.
On January 1, the new chick hatched to Elmer and Lima, who are two adult male Humboldt penguins who had developed a pair bond this breeding season, according to a news release.
Elmer was born in 2016, and Lima was born in 2019. The two are part of the zoo's 28-bird penguin colony.
The same-sex foster pair is a first for the zoo. Previously, the zoo has relied on such foster couples to incubate eggs. At least two breeding couples at the zoo have a history of accidentally breaking their fertilized eggs, so to give the egg a better chance, the zoo sometimes gives the breeding couple a dummy egg and gives the real egg to a pair that may have more success in incubating.
Elmer and Lima paired up in the fall, and the penguin team decided to test their fostering skills.
"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," zoo director Ted Fox said in the release. "That's how we evaluate who will be good foster parents -- and Elmer and Lima were exemplary in every aspect of egg care."
He said that the team discovered a fertilized egg in late December and decided to give it to Elmer and Lima to incubate. Fox said that the two took turns taking care of the egg and have been warming and feeding the chick since it hatched.
"At our first health check when the chick was five days old, it weighed 226 grams (8 ounces)," he said. "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."
Other institutions have reported good luck with same-sex pairs and fostering eggs, according to the zoo. Those include a female pair in Spain, a male pair in Berlin, and another in San Francisco.
Fox said that the zoo's same-sex penguin couple is another example of nontraditional families doing well at parenting.
"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," he explained.