There was a plan to add a rubber bondage dog gear, even an area was added to the game for it, but at the time I wasn't skilled enough to draw character sprites, and the idea was scraped, and the map replaced with the bottom part of the pig area.
I haven't yet decided what creatures will be joining the game in the future besides those from WIP areas and update votes. That will be likely decided spontaneously, just like the Tilcayo cat.