Why do babies kick their feet like maniacs?

God wants them to have strong leg muscles so they can walk?

They are exercising. Soon her will be wanting to crawl around and eventually stand up on those legs, if he does nothing with them the muscles will atrophy.

They do it because they are excited and happy. Body language is one way for babies to express themselves (in addition to laughing/crying).

As far as kicking and moving in their sleep, I think some of it is related to dreaming and the rest is just because they are trying to get comfortable. A lot of people move around quite a bit in their sleep.

For the same reason puppies like to jump on humans.

They are just babies.

Hey, thanks for asking a question that made me learn something new. Look at this link on infant reflexes under Plantar Reflex. It’s interesting that the kicking aids neurological development and also aids the birth process!
http://www.vitaehealth.com.au/retained-neonatal-reflexes/

They are developing gross motor skills. They can’t do much more until they get a good handle on those.

I think it’s because it’s one of the few things they can do.

They’re idiots.