The book was followed by a sequel, Fuzzy Sapiens (original title The Other Human Race) published in 1964, the same year that Piper died by suicide.

In the wake of Piper's suicide, rumor spread of a lost "second sequel"; in 1981, at the behest of Ace Books, William Tuning produced the critically acclaimed Fuzzy Bones.

Leonard Kellogg, one of Grego's staff, manages a team of scientists working to legally disprove the Fuzzies' sapience at all costs.

Kellogg kills himself in his cell, but the prosecution continues, and the court officially rules that the Fuzzies are sapient beings, invalidating the company's charter.

"Extee 3", "estefee", or "hoksu-fusso", meaning "wonderful food") does not coincide with the composition of Zarathustran soil, a contradiction of Garrett's Theorem.

Among other things, an alien spaceship is discovered on Beta Continent, and evidence that the Fuzzies are not in fact native to Zarathustra emerges, which raises a variety of legal and philosophical questions.

Tuning introduces a number of memorable characters, including Christiana Stone, Grego's Fuzzy-Sitter-in-Chief; Reverend Thomas Aquinas Gordon, aka "The Rev;" Master Gunnery Sergeant Philip Helton, TFMC; and Liana Bell, a CZC scientist invited by the researchers of Holloway's Fuzzy Institute to join them in their research.