(Image credit: Publico.Es)

A "gay" penguin couple in a Madrid zoo has been given an egg of their own to care for after six springs of building nests together and being disappointed their nests were empty.

Inca and Rayas, the Gentoo penguins at Madrid's Faunia Park have been inseparable for six years, according to the U.K.'s Telegraph. This year, the zoo gave them an egg to take care of.

"We wanted them to have something to stay together for - so we got an egg," zookeeper Yolanda Martin told the Telegraph.  "Otherwise they might have become depressed."

Martin said the attention the birds have attracted has been "lovely," though the penguins are not actually gay.  They're more like the best of friends, living cooperatively because they're in the same enclosure.

"When you put things in captivity, odd things happen," Kevin McGowan of the Cornell Laboratory of Ornithology in Ithaca, N.Y., told ABCNews.com. "The way penguins work is they do get paired for a long time. Basically, the only other penguin they care about is their mate, so it's important for them to find somebody who's compatible, and if you don't have a normal upbringing then it's difficult to say how 'normal' they can be."

The duo has enthusiastically taken to the roles of prospective parents. Inca has taken on the "female" role, spending his days devotedly sitting on the egg, according to the paper. Rayas has taken the "male" role, guarding the next and storing food in his beak as he prepares to feed the chick with regurgitated fish.

"In birds, it doesn't matter what sex you are. Both sexes are perfectly capable and absolutely necessary to raise a penguin bird," McGowan said. "It's not like mammals where only one sex can feed."

Two other "gay" penguin couples have made headlines recently.

In China, a popular "gay" penguin couple was given a newly hatched chick to care for in December. But a couple in Toronto, Buddy and Pedro, were separated and placed with female partners. The zoo said they warmed up to their new mates.

The Toronto zoo provoked a public outcry in November when it announced that the male penguins would be separated and paired with female penguins for mating.