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Hank Green: I don't have any children of my own, but I do have an awesome nephew and a brand new niece and many of my friends are doing a lot of baby-making these days, and the more I'm around these miniature little humans, the more I'm fascinated by all of the weird things about them.  

Did you realize, for example, that babies are born without fully developed tear ducts, this is why they cry all the time but they never cry.  Babies are also born with a natural instinct to crawl when placed low on a mother's abdomen immediately after birth, babies will shuffle up to the breast and start feeding.  That instinct vanishes soon after birth, and it will be another 7-10 months before the baby will actually crawl again, which is weird.  Scientists think babies do the breast crawl because they can smell the colostrum, the highly concentrated yellow-ish milk produced during the first few days after birth.  It's low in fat and high in protein and antibodies.  Apparently, they can also smell other attractive odors secreted by glands around the nipple.  

Amazing fact #3, a baby can not only recognize mom's voice from the moment he or she is born, but also while they are still inside of the person who's doing the talking.  Fetuses respond to all kinds of outside stimuli, slam a door and a third trimester baby will often move inside the womb, but they can also differentiate between voices from inside the uterus.  Studies have been conducted in which a pregnant mother and other random people read aloud to a baby in utero, they found that the baby's heart rate increases at the mom's voice, and slows down when it hears people who are unfamiliar.  Scientists call it an attention mechanism, the heartbeat slows down as the baby attempts to figure out who is making that strange noise.  

When the baby then recognizes mom's voice and instinctually knows how to crawl finally emerges, it will show up with about 270 bones in its body, which is 64 more than adult humans.  And because babies are born with bones that will fuse together over time, mostly in the skull and spine, babies begin life with a cranium made up of eight separate bones that eventually grow into one.  Infants need a soft, pliable head because otherwise, they wouldn't be able to exit through the birth canal, which is kind of important.  The soft spot at the crown of the head of most infants, which is technically known as the fontanelle, is an unprotected spot in the scalp where the bones fuse together, can basically poke a baby directly on its brain.

Finally, you've heard that babies can swim, but that's a dirty lie.  What's true, and pretty amazing, is a reflex called the bradycardic response, which causes infants to hold their breath and open their eyes when submerged in water.  This reflex stems from the nine very watery months the baby spent inside of a person.  So whether you have some of your own or not, maybe now you can appreciate babies on a whole new level, in addition to being adorable and stinky and often very noisy, they are also, in many ways, true marvels of nature.

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