15. They Have A Detached Collarbone
For us humans, the collarbone is an important part of the body, as it connects the arms to the torso. Any sort of injury to it will make your life much more difficult until it properly heals, which usually takes between four to eight weeks.
As for cats though, their collarbone isn't actually attached to anything It's just there, buried into the shoulder muscles.
Due to their collarbone not connecting to any other bone in their body, it allows cats to squeeze through tight spaces without causing any sort of serious injury to themselves. If their collarbone did connect to anything, then it would present numerous challenges with regards to a cat's everyday journey.
If, for whatever reason, you reading this attempted to prowl around like a cat, and tried to go through tight spaces, such as a cat flap, there's a near 100% chance you'll injure your collarbone, let alone other sections of your body. Some things are best left to our four-legged companions.