I'm actually reading about this subject right now!

To answer your question, it was mostly about the money. Fur, especially beaver pelts, was a very lucrative commodity and beaver-skin hats were height of fashion in Europe. French Canada was first settled for the acquisition of furs both directly and through the Indians and was owned directly by the fur trading Company of New France until 1663. So long as there was money to be made, men were willing to brave all sorts of challenges to claim it.

A sense of adventure and masculinity also played into pursuing the career of fur trapping. Fur trapping offered the opportunity to make a decent sum while conquering the "untamed wilderness." Directly venturing forth also allowed the Europeans to cut out the middleman and get the furs without having to go through the Indians. Most fur-trading was still done through the Indians and the two groups developed a mutual dependency upon one another.

Source:

• Alan Taylor. "Canada and the Iroquoia, 1500-1650". American Colonies