Can someone help me identify these bones

Question

These bone were found in western pennsylvania. It had my whole family confused on what kind of animal bone it could be.

I have 3 pics of the bone, here are the links:

http://i275.photobucket.com/albums/jj304/tylerox2/Bone001.jpg

http://i275.photobucket.com/albums/jj304/tylerox2/Bone002.jpg

http://i275.photobucket.com/albums/jj304/tylerox2/Bone003.jpg

Answer 1

mammothh ?

dogg with long fangs ?

vampire ?

lol  

Answer 2

Ima say a muscrat.

Answer 3

It looks like part of the lower jawbone (mandible) of some kind of rodent, probably a "groundhog."

The front teeth are for cutting and gnawing, and the rest are for chewing -- typical rodent.