Answer:
I have fangs and enjoy piecing holes with a single bite.
I'm at the head of an elephant and at the tail of a squirrel
What can be cracked before it's used?
I wiggle and cannot see; sometimes underground and sometimes on a tree. I really don't want to be on a hook and I become a person when combined with “book”.
I have a neck but no head. I have a body but no arm. I have a bottom but no leg. What am I?
It has no top or bottom, but it can hold flesh, bones, and blood all at the same time.