The length of tail is the Tenterfield Terrier’s most unique feature. It is the only terrier breed with tails that come in natural bob tails of various lengths, ranging from full tails through to no tail at all, which is referred to as a “rumpy”. Shown below is a range of lengths.
The natural bob tail results from a gene that has never been known to cause the breed any health issues (ie not a form of Spina Bifida).
The length of tail is not important - the set on and carriage of the tail must still be correct (as per the standard), as it acts as the indicator of the Tenterfield Terriers mood and temperament.
For many years now certain bloodlines within the Tenterfield Terrier breed have been carrying the bob tail gene. Sometimes entire litters are born with natural bob tails, and each puppy's tail in the litter can be a different length. Mating two non bob tails cannot produce a bob tail - genetically one parent must be a bobtail.
Breeders are required to identify pups with natural bob tails which is noted on the pedigree paperwork.