Due to genetic differences, French bulldogs can have short tails or long tails. When born, French bulldogs tend to have spiral-shaped tails and short tails. In order to make French bulldogs look cuter, their tails are docked. The tail of a docked French bulldog is as thick as the front and back, with no tapering shape at the end. Generally speaking, purebred French bulldogs have short tails and do not need to be tail-docked. If the tail is docked, most French bulldogs are cross breeds.