Figure 2. Distribution of the dogs according to severity of tail chasing behavior.

Only individuals that exhibit tail chasing behavior are included. Severity is described by the TC_index, which is a sum of two questions “Does your dog chase its tail?”(scale 0–6) and “On average, how much time on a normal day does the dog spent in chasing its tail? “(scale 0–6). (BT =  Bull Terrier, standard, MBT  =  Bull Terrier, miniature, GS =  German Shepherd, SBT  = Staffordshire Bull Terrier).