Back in the 80's Penguins were used to illustrate a classic reasoning challenge associated with belief systems - non-monotonic reasoning [0]. The story went like this: you are an AI building a cage for a bird called Tweety. You reason that the cage will need a roof and perhaps a tree or two for Tweety to perch in. After having built the cage, Tweety arrives and you discover that he is a Penguin.

So I have also been somewhat distrustful of Penguins, especially those appearing in AI teaching examples. Tweety actually appeared in a load of other AI examples, although I can't recall his specific escapades now.

[0] https://en.wikipedia.org/wiki/Non-monotonic_logic