Sphen and Magic rose to celebrity status in 2018 when they began collecting pebbles to create a nest and became almost inseparable, regularly seen waddling around and swimming together.

The duo were together for nearly six years, roughly half their average life span, and began expanding their family soon after. They co-parented two chicks, Lara, in 2018, and Clancy in 2020. Lara was nicknamed Sphengic after her parents by the public.

“It was a beautiful example of co-parenting as a same sex couple,” Vincent Savolainen, a professor of organismic biology at Imperial College London, told NBC News.

The parents would swap between patrolling their nest perimeters to ward off thieves and incubating the egg.

Zookeepers said Sphen and Magic were natural at parenting and had been given a real egg from a couple who had two eggs so that they were not excluded from the breeding season.

Homosexual bonds in animals, including birds, has been widely documented, experts say, often noticed as a desire among the couple to co-parent an offspring.

“It’s quite common in birds that two of them will get together for co-parenting,” said Savolainen. “That can happen for multiple reasons, usually it could be advantageous, for example two males can co parent because they’re stronger and are better able to protect the egg,” he said.

“Whether it is really homosexual behavior, one can debate,” he added.

Their love story was more than just fame for the zoo, as they rose to become icons of homosexuality in Australia and beyond.

The duo was also found together outside of their usual breeding season, which according to the zoo is unique for Gentoo penguins.