Why did the baby learn to run?

[pomes]

Both hands up and both fists full
Her eyes and her mouth are open wide
And her feet are pounding the floor until
She finally gets to the other side -

Crawling was good, as a starting point,
And walking was better - it freed up her hands.
Running is best because the faster you start
The further you go before you have to land.

Walking was easy, once she got going
And this one was born with an urge to get gone
So she's practicing running and when she stops falling
She'll deftly up sticks and swiftly move on.