When you have a baby, even if you can't sing, you sing. Lots. When you are frazzled, tuckered, and frumplumped (an FF word meaning a combination of twisted and bloated) by the day. You sing until it nearly convinces you to forget about your former grumpy state. I'm in the process of compiling lyrics and melodies for an album of kiddy music inspired by my little booger bean.
Here's a mix of lullabies sung by mammals around the world: