Each of D's rare pets, which all have strangely humanoid appearances, comes with a contract with three major points.

The three species share many similar features such as pointed ears, humanoid appearance, and limited telepathic abilities.

Aranimas was clearly an alien, despite his superficially humanoid appearance.

"The fact that he has a humanoid appearance would make him a stand out in this crowd."

As they had before, the Organians assumed a generally benign, non-threatening humanoid appearance.

Despite his halfhearted attempt at a humanoid appearance, the Changeling looked more like an illusion than a real being.

He had never been able to get the humanoid appearance quite right; his features seemed flattened, two-dimensional.

Perhaps the Thassa themselves, for all their humanoid appearance, were farther apart from the off- worlders who used that scale than he knew.

The humanoid appearance, friend Daneel, cannot be fought off when that is all one can directly judge by.

I guess the same mindset is what led them to retain their humanoid appearance even after all these years.