Looks like same-sex animal couples are similar to humans in this sense

[theking]

 :

Same-sex penguin couple welcomes baby chick

A pair of female penguins at an aquarium in Spain have welcomed a baby chick, the Oceanogrŕfic Valčncia aquarium announced this month. The two penguins, Electra and Viola, adopted an egg from another penguin couple, incubated and hatched it, and will now raise the chick..

[YAX]

They are.

See:
https://www.youtube.com/watch?v=ZG94JH4FGMk