A pair of male emperor penguins at a zoo in Germany have taken it upon themselves to care for an egg laid by a female with no interest in hatching it.
Skipper and Ping were already a bonded pair when they came to the Berlin Zoo in April 2019. When they were introduced to the general population, they immediately started displaying a desire to become parents.
According to German news agency DPA, the duo would snatch fish and stones and sit on them to try and make them hatch. Zoo officials chose to harness that parental instinct with a real egg laid by another bird in the group.
The Berlin Zoo's has six emperor penguins, with only one female, who is nearly 20 years old. She's demonstrated little to no interest in her eggs and none have hatched successfully.
In the wild, a male emperor penguin works to keep eggs warm after the mother has laid them, giving her time to regain her strength and gather food. Both Skipper and Ping are taking turns on egg-sitting duty, using their beaks to gently roll it onto their feet and then enfolding it within their warm belly flaps.
"The two penguin males behave like exemplary parents and warm the egg alternately," zoo spokesman Maximilian Jäger told Berliner Zeitung.
An emperor penguin typically takes around 55 days to hatch from its egg, so Skipper and Ping are more than halfway there. If the chick survives, it will be the first new emperor penguin born at the Berlin Zoo since 2002.
There is some concern, though: Zookeepers aren't sure if the egg was ever fertilized.
Male penguin couples have been observed numerous times, both in captivity and in the wild, and have hatched eggs elsewhere locations. Ronnie and Reggie, a duo of Humboldt penguins at the London Zoo, paired off in 2014 and hatched an egg together the following year.
The zoo even uses the birds as the mascots of their Pride month celebration.
In 2017, Sphen and Magic, two male gentoo penguins at the Sea Life Sydney Aquarium built a nest and, after practicing with a fake egg, hatched a real one the zookeepers gave them.
Roy and Silo, a pair of male chinstrap penguins at the Central Park Zoo who hatch an egg and raise a baby chick together inspired the 2005 children's book And Tango Makes Three. The book won the American Library Association's Notable Children's Book Award but was also the subject of numerous protests, with the ALA reporting it was their most challenged book from 2006 to 2010.
In 2017 a pair of male griffon vultures hatched an egg at the Artis Amsterdam Royal Zoo. According to Yale Scientific magazine, more than 450 different animal species, from giraffes to tortoises, have been seen to exhibit same-sex attraction.