o:2309 Equine Social Behaviour: Love, War and Tolerance en Sociality is an ethological need of horses that remained unchanged by domestication. Accordingly, it is essential to include horses' social behavioural requirements and the opportunity to establish stable affiliative bonds in equine management systems and welfare assessment. Thus, this systematic review aims to provide an up-to-date analysis of equine intraspecific social ethograms. A literature review yielded 27 papers that met the inclusion criteria by studying adult (≥2 years) equine social behaviour with conspecifics using a well-defined ethogram. Social interactions were observed in 851 horses: 320 (semi-)feral free-ranging, 62 enclosed (semi-)feral and 469 domesticated, living in groups averaging 9.1 (mean +/- 6.8 s.d., range: 2-33) horses. The ethograms detailed in these 27 studies included a total of 40 (mean: 12.8/paper, range: 2-23) social behaviours, of which 60% (24/40) were agonistic, 30% (12/40) affiliative, 7.5% (3/40) investigative and 2.5% (1/40) neutral. The 27 publications included 67.7% agonistic and only 26% affiliative, 5.1% investigative and 1.2% neutral social behaviours in their methodology, thus focusing predominantly on socio-negative interactions. The strong emphasis on agonistic behaviours in equine ethology starkly contrasts with the rare occurrence of agonistic behaviours in stable horse groups and the well-established importance of affiliative interactions for equine welfare. The nuanced and complex equine social behaviour requires refinement of the ethogram with a greater focus on affiliative, ambivalent and indifferent interactions and the role of social tolerance in equine social networks to advance equine welfare assessment. Horses Equus-Caballus; Feral Horses; Reproductive Success; Przewalski Horses; Domestic Horses; Young Horses; Sorraia Horses; Paddock Size; Older-Adults; Herd 1552099 10.3390/ani13091473 2023-11-14T09:42:52.160Z 44 yes 46 Laura Torres Borda University of Veterinary Medicine Vienna Ulrike Auer University of Veterinary Medicine Vienna person 0000-0003-0390-2678 Florien Jenner University of Veterinary Medicine Vienna person 0000-0002-6977-1984 application/pdf 354823 https://phaidra.vetmeduni.ac.at/o:2309 no yes 16 70 1552253 Animals 22 13 9 MDPI 2023