Are there animals that raise other animals' younglings as their own?

In what’s known as brood parasitism, cuckoos lay eggs in the nests of other bird species, to be raised by the unsuspecting hosts. The word cuckold derives from this.

A cowbird slipped its egg into a cardinal nest in our yard one year. They raised it as their own. Even after it grew larger than it’s adoptive parents, it would perch near our bird feeder and whine and the cardinals would dutifully dart back and forth, eating sunflower seeds and regurgitating for their over-sized baby. ( Picture )
Here’s a story (not mine) about cardinals and cowbirds. Interesting that the cowbirds join cowbird flocks after leaving the nest. Ingrates!

The Cardinal and the Cowbird
http://spwrc.org/index.php?option=com_content&task=view&id=2&Itemid=1

In the Life documentary, two Japanese red bug mothers compete over some food. When the one loses and takes too long to bring food back for her young, they go off in search of food for themselves. They end up joining with the other mother’s brood, so she arrives with the food to find her brood has doubled in size. She then has to work double-time to provide for all of them, and in the end works herself to death.

I’ve also heard of dogs adopting orphaned cats, squirrels, ducks, etc. Walruses have also been known to adopt orphaned walruses.

I saw a documentary once where these monkeys (don’t know which type) stole some kind of wild puppy to keep it as their own. Can’t give you any more information other that the wild dogs didn’t want them to take it and they were trying to fight the monkeys off.

There have also been a fair number of cases of feral children being raised by wild animals. It doesn’t work very well though.

@fundevogel Wow, really G.A. thanks for the link!