Thanks to community modding tool Sims 4 Studio, it was discovered that some brand new CAS Parts have been added to the game, but not yet available for use. FurBody, Ears, Tail, FurEars, and FurTail, are CAS Parts that show up within the tool.
These CAS Parts are by no means officially confirmed, but they are showing up within the code and unlocked by Sims 4 Studio’s program. Perhaps we can expect to see these items added to the rumored Pets Expansion in the future.