The Australian Stumpy Tail Cattle Dog, commonly known as the Stumpy, is a naturally bobtailed or tailless medium-sized cattle dog closely related to the Australian Cattle Dog. The Australian Stumpy Tail Cattle Dog and the Australian Cattle Dog share Halls Heeler origin.
Image credit: Wendy Hodges, CC BY 2.0
Adapted from Wikipedia, CC BY-SA 4.0 — https://en.wikipedia.org/wiki/Australian_Stumpy_Tail_Cattle_Dog