Are Babies Born Without Kneecaps? 6 Facts Almost Nobody Knows
Newborns hold more surprises than you might think, from knees that don't show up on X-rays to cries that mimic their parents' language. Here we answer six common questions about babies with clear explanations.
Are Babies Born Without Kneecaps?
No. On a newborn's X-ray, the knee appears to have no kneecap. But the kneecap is there, made of cartilage. It's the same tissue you can feel at the tip of your nose, and it doesn't show up on X-rays.
That cartilage starts turning into bone between the ages of three and six. The process isn't complete until adolescence. Once it is, the kneecap is the largest of the bones that form inside a tendon.
Why Do Newborns Cry Without Tears?
It's common to see a baby screaming with completely dry eyes. Newborns almost never cry with tears.
From day one, their glands produce a film that keeps the eye moist. However, they don't produce any more than that yet. They make just enough to keep the eyes hydrated, not enough to overflow. Tears when crying usually appear between the first and third month.
Do Babies See in Black and White?
It's a widely repeated myth. Babies perceive color from very early on, although it looks very faded, like a photo with the saturation turned almost all the way down. The reason is that the cones, the cells in the retina that detect color, are still immature.
The first color they can clearly distinguish is red. By around four or five months, their range of colors already resembles an adult's. They also focus best at about twenty to thirty centimeters, the distance to the face of whoever is feeding them.
Why Do Babies Have Soft Heads?
Because their skull hasn't closed yet. It has fontanelles, areas where the bones haven't fused, covered by a tough membrane.
During birth, these bones overlap so the head can fit through the birth canal. Afterwards, they make room for the brain, which doubles in volume during the first year. A closed skull couldn't grow along with it. The fontanelle at the back closes at around two months. The one on top closes between one and two years of age.
Does Listening to Mozart Make Babies Smarter?
This is often repeated, but the original study, published in Nature in 1993, didn't include a single baby. The participants were university students who, after listening to a Mozart sonata, improved slightly on a spatial reasoning test for about fifteen minutes.
Even so, in 1998 the governor of Georgia, Zell Miller, proposed using public money to give every newborn a classical music CD. Later reviews, covering dozens of studies, concluded that the effect is minimal or nonexistent.
Can Babies Hear in the Womb?
Yes. By around week twenty, the inner ear is already working. A few weeks later, the fetus reacts to sounds from outside. From inside, everything sounds like a neighbor's music through the wall: the words can't be made out, but the rhythm and melody come through.
In 2009, researchers from Germany and France recorded the cries of sixty French and German newborns aged three to five days. The French babies cried with a melody that rose at the end. The German babies cried with one that fell. This matched the intonation of each language. Before saying their first word, a baby already cries with an accent.
Frequently asked questions
When do babies start crying with tears?
Tears when crying usually appear between the first and third month. Before that, their glands only produce enough to keep the eyes moist.
When do the fontanelles close?
The fontanelle at the back closes at around two months. The one on top closes between one and two years of age.
What color do babies see first?
The first color they can clearly distinguish is red. By around four or five months, their color vision already resembles an adult's.
From what week can a fetus hear?
By around week twenty, the inner ear is working. A few weeks later, the fetus already reacts to sounds from outside.
Informative article written with the help of AI tools from the verified script of the video. The video is in Spanish.