Here's why:
* Different categories: "Medium" can be interpreted differently for different animal categories (e.g., insects vs. mammals). A medium-sized insect would be tiny compared to a medium-sized mammal.
* Wide range of sizes: Within each category, there's a huge range of sizes. A medium-sized dog could be much smaller than a medium-sized horse.
* Subjectivity: What one person considers "medium" another might consider "small" or "large."
Instead of looking for the "most medium-sized" animal, it's more helpful to consider:
* What specific category you're interested in: Are you thinking about mammals, birds, fish, insects?
* What size range you're considering "medium": Are you looking for something smaller than a horse but bigger than a cat?
Once you've defined your criteria, you can start exploring the amazing diversity of animals that fit within that size range!