Research overview: the tail-up signal in domestic cats

The vertical tail-up posture is one of the most studied visual signals in domestic cats and is widely interpreted as a friendly intention signal that precedes approach, allorubbing, and amicable interaction. Comparative work suggests tail-up is rare or absent in the cat's wild ancestor and may have been elaborated during domestication and group living, making it a marker of social tolerance. This overview surveys observational and experimental findings, including studies using silhouettes that show cats respond to the posture itself. It explains why tail-up is a reliable indicator of positive social motivation in colonies and households and a useful welfare cue.