21 Science Facts You Won't Believe Are True

12. Newborn Babies Don't Cry Tears

As much as we might associate babies with crying (and pooping and not much else), newborns don’t actually produce tears, even though they make crying sounds.

This is because they are born with underdeveloped tear ducts that can only produce enough fluid to keep their eyes moist and will only cry "real tears" after about 3 - 12 weeks. Weirdly, newborns will produce excess tears to remove dirt and irritants from eyes, they just won't waste them on being upset. Perhaps this is a lesson we could all learn.

11. Female Babies Can Sometimes Menstruate

Sticking with just how weird babies are for a second, female newborns can sometimes experience what is known as pseudomenstruation within the first week of life.

When babies are in the womb, they are bathed in high levels of the female hormone oestrogen from the mother, but after birth these levels quickly take a dive. In adult women, the sudden drop in oestrogen during the menstrual cycle is what triggers a period, and the same happens in some babies, which can be alarming for parents who aren't aware of the phenomenon.