It's important to note that:
* Tail docking was a common practice in the past, but it's now considered unethical and illegal in many places. This means that some older Chihuahuas may have had their tails docked.
* Some Chihuahuas may have naturally short tails, but this is a rare occurrence and not a characteristic of the breed.
If you're unsure about the tail of a specific Chihuahua, you can ask the breeder or owner about its history.