Vigilance behaviour in Siberian ibex (Capra sibirica): Effect of group size, group type, sex and age

Is vigilance a personality trait? Plasticity is key alongside some contextual consistency

“…Animals routinely interrupt their current behaviour to scan their environment for potential threats, particularly from predators. Grouping helps to reduce the costs of vigilance to detect predators [ 1 – 4 ] but increases demand on monitoring conspecifics (social vigilance; [ 3 , 5 – 8 ]). However, there is increasing evidence that individuals in a group differ in their vigilance due to differences in state, sex or age (e.g., [ 2 , 9 , 10 ]).…”

“…Vigilance is often measured in a foraging context to investigate trade-offs between foraging and vigilance [ 11 ] by assessing the frequency and duration of heads-up (e.g., [ 4 , 9 , 11 , 12 ]). More recently, primarily horizontal head movements (in contrast to primarily vertical head movements) have been used to measure vigilance.…”

“…Differences in vigilance between individuals in a group can be linked to their vulnerability; females in size dimorphic species are more vigilant than males [ 10 ] as are individuals at the periphery of groups [ 18 ]. Whereas age seems to follow an inverse U-shape curve with juveniles [ 9 , 19 , 20 ] and old adults [ 4 , 21 ] being less vigilant, potentially reflecting the need for higher food intake in juveniles, whereas bigger size or senescence may be the reason in adults.…”

“…Vigilance in groups with young is higher than without young [ 18 ], particularly in females with young [ 5 , 8 , 10 , 20 ]. Moreover, in ibex ( Capra sibirica ) female groups and mixed sex groups were more vigilant than male groups reflecting the higher predation in female groups and social vigilance directed towards harassing males in mixed groups [ 4 ]. Higher vigilance has also been observed in colour polymorphic species when in mixed morph groups as compared to monomorphic groups again indicating social vigilance [ 22 ].…”

Different environmental requirements of female and male Siberian ibex, Capra sibirica

“…Since Alpine ibex ( Capra ibex ibex ) females and males showed habitat segregation during summer 22 , we also expected similar behavior in Siberian ibex, to maximize survival and reproduction success, females and males would select different habitats. Considering the more vulnerability of females to predation risk compared to males 23 , 24 , we predicted that females would prefer more rugged terrain than males in favor of safety of their offspring and themselves. In addition, our previous observations demonstrated that males preferred the most abundant plant species that can supply the greatest volume of food irrespective of its quality, while females selected plants based on their higher nutritional content 24 .…”