Understanding feline social dynamics : a video-based observational study on allogrooming in domestic cats

Allogrooming is a behaviour performed by various animal species to promote hygiene and/or maintain social bonds. Also domestic cats perform allogrooming, commonly described as a sign of social group formation, although the behaviour remains highly understudied. We performed a video-based observational study to gain a deeper understanding of the function(s) of allogrooming in cats. Citizen science was used to collect videos of 53 cat dyads during allogrooming. Behavioural observations with ethogram were performed by two observers, rendering good reliability (Cohen’s Kappa ≥0.78). Statistical analysis in R (version 4.3.2) included creation of a linear mixed model comparing duration and frequency of behaviours across cats grouped according to (1) performance of allogrooming (groomer/groomee), (2) relatedness and socialisation (related/unrelated), and (3) synchronisation of body posture within the pair (synchronous/asynchronous/dynamic). Groomers performed more (p=0.017) and longer (p=0.026) autogrooming, and more object sniffing (p=0.019), both possible displacement behaviours, while groomees showed more interactive body postures as seen during playful or aggressive encounters (p=0.028). Despite social group formation typically being reserved for related and early socialised cats, 24 cat dyads in the study were unrelated but did groom each other. No further behavioural differences were found based on relatedness. Lastly, cats synchronising their body posture during allogrooming, seek more often (p=0.022) and longer (p=0.0005) physical contact, avoid the other cat less (p=0.023) and perform less displacement shaking and scratching (p=0.045). Our results illustrate that feline social dynamics are complex and behaviours such as allogrooming might serve multiple social functions.