A gay male Humboldt penguin couple at Munich Zoo are brooding over a rock because they have no egg to care for.

The revelation was made when Munich Zoo joined in with the city’s Pride week by giving a tour of the zoo’s gay animals, which include penguins, giraffes and lions.

As the tour passed the penguin enclosure, the guide pointed out that the two black-faced male penguins squatting together were trying to hatch a rock, whereas other mixed-gender penguin couples were brooding eggs.

According to the AFP, biologist Guenter Strauss said that the gay male pair were not having a “one-off fling” but were in a committed relationship.

“Penguins conduct homosexual relationships that can last a whole lifetime, something very rare in the animal kingdom. It is important for us to talk about” homosexuality in the animal kingdom and show that same-sex love has its place in nature, said Munich zoo spokesman Dennis Spaeth. “Because unfortunately in Germany we see more and more people from the reactionary right attacking LGBT+ rights,” he said.