On the topic of cats and purring, apparently the purr of a cat mimics the frequency that distressed infants make [1]. I personally can't confess to ever mistake a cat's purr for anything but a purr, but it's interesting to think about how cats might have evolved to manipulate humans into giving them food.

1. https://www.cell.com/current-biology/fulltext/S0960-9822(09)...