What follows is a complete list of all animals I have observed from my window:

• Bunny
• Cat
• Dog
• Frog
• Golden eagle
• Hawk
• Lizard
• Raccoon
• Snail
• Snake
• Squirrel
• Tortoise

It appears that animals fall into three distinct categories: feathered, hairy, and neither. The snail poses the biggest challenge because it has no legs. It was also the only animal without feathers that lays eggs in my list for almost a year.

For some time, I felt that snails must be an anomaly. Perhaps snails are actually bugs, but then I discovered the snake. It was another animal with neither hair nor feathers and has no legs. This turned my understanding of animals on its head.

Thus, I think the three classes of animals are best described as:

• Those with feathers. These animals always fly, lay eggs, and have legs.
• Those with hair. These animals always have legs. They never lay eggs.
• Those with neither feathers nor hair. These animals always lay eggs, but most do not have legs.

I observe that animals that lay eggs never have hair. Thus, we might subdivide a different way if we use a tree structure.

• Egg layers: Never have hair
  • Feathered flyers: always have legs
  • Non-feathered, non-fliers: may have legs
• Non-egg layers: always have hair, always have legs.

I admit, there’s quite a few ways to begin describing these clusters. I’ll update this post if I observe more animals.