In TOS, Kirk asked Sargon why he kept calling them "his children". Sargon told Kirk that they seeded the galaxy with their likeness eons ago. Kirk responded that there was evidence for independent development of humans on Earth but Spock said this seeding would explain Vulcan mythology. One of the appealing features of the TOS as originally pitched to DesiLu was that they would visit "Class M" planets, so humanoid.
My housemate had an obese (26 pd) neutered cat. He always used the litter box but he was so huge that a couple of times we found found poop on the floor because his read was hanging over the litter tray.