Answer:
What is made of wood but can't be sawed?
With head without hair. With mouth without tooth.
What is it which builds things up? Lays mountains low? Dries up lakes, and makes things grow? Cares not a whim about your passing? And is like few other things, because it is everlasting?
Metal or bone I may be, many teeth I have and always bared. Yet my bite harms no one. And ladies delight in my touch.
I have four legs but no tail. Usually I am heard only at night.
I am your mother's brother's only brother in law. Who am I?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?