Unravelling feline social dynamics - A video-based observational study on allogrooming in domestic cats

There are conflicting hypotheses about the social function of allogrooming in domestic cats; a main hypothesis is that allogrooming is used to establish and maintain social bonds. However, this hypothesis lacks empirical support. Therefore, we performed a video-based observational study to inductively infer the social function(s) of feline allogrooming. Videos of 53 cat dyads (106 cats) during allogrooming were analysed with a 23-item ethogram. Statistical testing included (i) test on body regions targeted during auto- versus allogrooming sessions, (ii) a Factor Analysis to explore which behaviours covary with allogrooming, giving a broader understanding of the context in which the behaviour occurs, (ii) LAG Sequential Analysis to evaluate the patterns within these interactions in terms of the behaviours that precede or follow allogrooming, and (iv) a linear mixed model to assess if allogrooming-interactions differ according to relatedness, grooming-behaviour or symmetry in body posture. The combined analyses demonstrates two contexts in which allogrooming commonly occurs, (1) social bonding/affiliation and (2) social tension. In these contexts, allogrooming might fulfil differing functions, distinguishable on the basis of wider behavioural features. Firstly, allogrooming may strengthen social bonds when cats seek mutual, long-lasting physical contact (mainly huddling), synchronise their body postures (sitting, lying), and wrestle following allogrooming in a pre-play-context. Secondly, allogrooming may serve to resolve conflict acting as either an appeasement gesture or a subtle agonistic threat. At these times of social tension, asymmetric body postures (i.e. one cat leaning over the other) ears rotated backwards, and the frequent expression of displacement behaviours (lip licking, head shaking) or overtly aggressive behaviours (striking, biting) are also apparent. These results highlight the potential importance of wider behavioural/postural synchrony to understanding the function of allogrooming.