Island of the Blue Dolphins what tool karana uses for cutting poles?

The question should read; "In the novel, "The island of the Blue Dolphins", by Scott O'DELL what did the character Karana use for cutting poles?


I can't see any reference to the tool she used for cutting poles, but she did indeed cut poles to make spears and used "sea elephant" (walrus?) teeth to make the points. I can only guess that she used a flint knife if she had no access to metal.