Variation in the sacroiliac joint in Felidae

Felidae species show a great diversity in their diet, foraging and hunting strategies, from small to large prey. Whether they belong solitary or group hunters, the behavior of cats subdue resisting prey presents crucial differences. It is assumed that pack reduces per capita risk each individual. We hypothesize sacroiliac articulation plays key role stabilizing predator while subduing killing Using CT-scan 59 felid coxal bones, we calculated angle between both iliac articular surfaces. Correlation this inter-iliac with body size was ecological stressors were evaluated on angle. Body significantly influences having wider than big cats. Arboreal have larger compared cursorial felids smallest value, scansorial terrestrial intermediate angles. Felids smaller mixed Within Panthera lineage, hunters (lions) all other using strategy. According angle, two main groups are determined: (i) predators an around 40° include (i.e., Felis silvestris, Leopardus wiedii, Leptailurus serval, Lynx Canadensis, L. rufus ; median = 43.45°), only pack-hunting leo 37.90°), arboreal Neofelis nebulosa 49.05°), (ii) 30° solitary-hunting Acinonyx jubatus, P. onca, pardus, tigris, uncia 31.80°). suggest different pressures selection interpret these results. The tightening wings sacrum probably enhances cats’ ability for high speed control. In contrast, lions reduced selective pressure