Let's go with... "Do all species of animals have butts?"
This is an interesting question because it makes us think about the diversity of animal bodies and how they function. While humans and many other animals have a distinct buttocks area, not all creatures are built the same way.
In fact, some animals like starfish, jellyfish, and worms don't really have a butt in the classical sense. They might have an anus or a opening for waste removal, but it's not necessarily located at the back of their body or surrounded by a pair of buttocks.
On the other hand, many animals do have butts that