When a newborn baby is placed on his mother’s stomach so that she can embrace him, it is no accident that the umbilical cord is of just the right length – approximately 20 inches – to make this possible while the baby is still attached to the placenta.
The bony plates of a baby’s skull remain separate after birth. Small gaps between them are covered by a tough, membranous tissue that is strong enough to resist all but a sharp, direct blow. The plates eventually touch, forming wavy sutures which become harder and stronger until the skull is fused; in most cases, this takes between 18 and 24 months.
A full-term newborn has a secret weapon – “brown” fat. This special type of fatty tissue, which burns calories, makes up five per cent of the baby’s body and is located in the back, shoulders and neck. It liberates heat through a special chemical process if the baby’s body starts to cool unduly.
If a parent presses their forefingers into the palms of a newborn baby’s hands, his tiny fingers respond by curling tightly and clinging on. Amazingly, if the parent then gently lifts the clasped forefingers, the baby’s grasp is usually so strong that his whole body can hang in mid-air, with his bent fingers supporting his weight.
The resting heart rate for an infant (115 pulses per minute) is about the same as that of an adult who has been performing strenuous exercise.
A baby can identify his mother by her unique body fragrance and a blindfolded woman has the ability to identify her child from a host of other babies by scent alone. A sleeping mother can identify the cry of her baby, too. She is programmed to wake only at the sound of her particular infant.
Adults respond to particular features – found in their most exaggerated form on a baby’s face. These include a large forehead, a button nose, big eyes, fine hair and a small chin. When an adult sees an unfamiliar baby face, so powerful is the instinct that the brain reacts within one-seventh of a second.
The average weight of a baby at birth is 7-8lb, but the smallest baby ever to survive (a premature one) weighed only 8.5oz at birth. The heaviest weighed in at 22lb.
The exact number of infant bones varies but there are usually about 270 at birth compared to an adult, who has 206. The reductions take place in the central skeleton, owing to the fusing together of bones in the spine and skull. A baby is born without ossified kneecaps – these do not develop until he is two years old.
During his first week outside the womb, a typical baby sleeps for 16.6 hours out of every 24 in as many as 18 separate naps. By the age of six months, his total sleep time is 14 hours, and by the age of five, it is down to 12 hours per day.
One in 10 children is left-handed; from studies of ancient axe handles, we know this bias has existed for at least 200,000 years. A clue may lie in the fact that the majority of babies lie in the womb with their right sides closer to their mother’s body surface, therefore it receives more stimulation during pregnancy.
Girls are more sensitive to touch than boys – on average, girls just a few hours old react to a weak puff of air against their belly and squirm and cry more than boys when uncovered. Other investigators have found that plenty of skin contact produces babies who cry less and are healthier.
The brain of a child is much busier than that of an adult. In the brain of a newborn, there are about 2,500 synapses (connections between brain cells) attached to each of the 10 billion neurons or brain cells he possesses. In a two-year-old, this number rises to 15,000 – more than in the brain of adults, who lose some of these connections over time, as the ones that are used less are eventually eliminated.
When a toddler reaches the age of 15 months, a moment of truth arrives. He looks in the mirror, waves his hand, and the “other person” waves back in exactly the same way. The child realises that what he sees is himself and not another child. Apart from human toddlers, only chimpanzees, orang-utans, dolphins, elephants and just one gorilla have managed this with any certainty.
Even at the 26th week of pregnancy, it is possible to distinguish a male foetal brain from a female one. Male babies have brains that are more asymmetrical than female babies. They also have more white matter and less grey matter. In female brains there is more symmetry in the “higher association cortex”; the part of the brain that deals with complex mental processes.