What term describes dogs born without tails or with very short natural tails?

The story behind the answer

Bobtail is the term for dogs born with no tail or a naturally short one. It describes a congenital “bobbed” tail, unlike docked, which is a surgically shortened tail after birth. “Stumpy” is a breed nickname (e.g., Australian Stumpy Tail Cattle Dog), and “rumpy” is mainly used for tailless Manx cats.

Many natural bobtails are caused by a mutation in the T-box (T) gene; dogs with one copy show the short tail, while two copies are usually lethal to embryos. Breeds like the Pembroke Welsh Corgi and Australian Shepherd can carry this gene. Memory tip: think “bobbed hair”—short by nature—and remember the Old English Sheepdog’s nickname “Bobtail,” given when its tail was docked, which helps link the word to short-tailed dogs.