Short Tails

While some dogs short tails are natural, called bobtails, many dogs you come across will actually have docked tails.
The term 'docked tails' refers to a dog's tail that has been intetionally cut off as a puppy, often times to fit breed standards. Examples of both can be seen below.


Bobtails



Australian Stumpy Tailed Cattle Dog


Docked



Boxer Doberman


Both

Believe it or not, some dog breeds have both natural and docked tails!


Brittany




Image Sources
Australian Stumpy Tailed Cattle Dog
Brittany (short) Brittany (long)