Little Fuzzy by H. Beam Piper [Revised Edition]

One day Jack Holloway, prospector on the planet Zarathustra, finds what seems to be a small monkey with golden fur; these new introductions (for the first brings a family) are tiny hunters, and prove to be curious and capable tool users. Why is this so important to the new human settlers? - Because a planet inhabited by a sapient race cannot be monopolized by the Zarathustra Company.

Winner of the 1963 Hugo Award.