H. Beam Piper

Little Fuzzy is a science fiction novel set on the planet Zarathustra, a world rich in natural resources being exploited by a huge chartered company from Earth. Jack Holloway is a free-lance sunstone miner working on the outskirts of civilization when he encounters a small, fuzzy animal which turns out to be remarkably intelligent. He soon begins to suspect that "Little Fuzzy" and his family are more than just clever animals, but in fact a new sapient alien species.
Such a proposition is directly opposed to the interests of the chartered Zarathustra Company, and conflict ensues. Published in 1962, Little Fuzzy rapidly gained popularity due to the charming nature of the little aliens and the well-handled tensions of the plot. It is today considered to be a classic of the genre, though perhaps considered to fall into the category of juvenile fiction. It was followed by a sequel, Fuzzy Sapiens in 1964.