This may be a strange question, but really it's something I've always wondered.
Recently I was watching a documentary of penguins and how a mother penguin lost its child. Then it went looking for it, and among a horde of penguins, it was able to find it's child and take it.
What really intrigued me is that the penguins looked exactly the same. Animals don't have "as much" distinctive features as we humans do, such as significally different hair color, skin color, they don't really look very different. Rather animals of the same species look very similar.
How can one even differentiate between all these penguin children? Even the parents look very similar.
That's just what I'm wondering. How can parents spot their child between all of these penguins that look almost identical.