What Am I Riddles

Question: You use me from your head to your toes,
the more I work the thinner I grow.

What am I?

Question: You bury me when I'm alive,
and dig me up only when I die.

What am I?

Question: Crawls over pages and fells wild beasts.
Helps guide you along in your home and on streets.

What is it?

Question: I'm the part of a bird that's not in the sky,
I can swim in the ocean and remain dry?

What am I?

Question: What gets easier to pick up the larger it gets?