Once while I was travelling on the train I've heard a little part of a conversation between 2 siblings, a 6year-old boy and an older girl. That was it:
"-... the girl eat the boy.
- As at the mantises do. The female mantises eats the male.
(Brother's staring at Sister, scared about the fact He heard before. Squirms 'till he gets smaller. Then looks out of the window, and continues with a smiling voice: )
- How lucky that people don't do it. "
(And if it's true or not...it's another story. :) )