The slow child

When an animal gives birth to smaller ones, immediatly the junior would move, spot the mom and starts sucking milk. In few days, the puppies or other offspring would run around, understand the world around, pick a fight with its sibling, try to chew anything that is available. What a fast track life.

Compared to that human child is very slow. After three months of looking after it, we are very happy to hear some noise out of it. With few more months, it starts pushing itself around - making us immense proud. Another six month to stand, try to walk, play with words. Would have to wait for four to five years to reliably be on its own and cross the mid-teen to be productive and able to lead a life.
This difference between animal growth and human always puzzled me. Reading Bill Bryson's book clarified the doubt. Giving a passage from his book:

Bipedalism is a demanding and risky strategy. It means refashioning the pelvis into a full load-bearing instrument. To preserve the required strength, the birth canal in the female must be comparatively narrow. This has two very significant immediate consequences and one longer-term one. First, it means a lot of pain for any birthing mother and a greatly increased danger of fatality to mother and baby both. Moreover, to get the baby's head through such a tight space it must be born while its brain is still small - and while the baby, therefore, is still helpless. This means long-term infant care, which in turn implies solid male-female bonding.

May be the smaller brain allow us to learn the stuff after birth. Wheareas animals comes with almost pre-moulded brain and the scope for them to learn is limited. So, our hardwork in terms of taking risk and going thru immense trouble paid off well.