Paying attention to attention: intrinsic and extrinsic factors affecting vigilance bout and stare durations in bighorn sheep

The process of organizing and interpreting sensory information, known as perceptual processing, is a key feature of adaptation allowing animals to integrate, assess and cope with challenges in their environments. Here, we examined the durations of vigilance bouts and stares in bighorn sheep, Ovis canadensis, as an indicator of time spent vigilant and perceptual processing, respectively. We tested the extent to which vigilance was shaped by relevant ecological factors, focusing on predation risk. Specifically, we tested whether stare duration increased when sheep were younger, part of smaller groups, further from others, further from escape terrain or closer to obstructive cover, all of which are expected to affect individual predation risk. Perceptual processing in bighorn sheep conformed to the 1–4s perceptual window found in other mammals, consistent with the idea of a phylogenetically conserved mechanism across mammalian species but was variable within individuals, indicating that perceptual processing is plastic to relevant ecological contexts. As expected, stare duration was much shorter than vigilance bout duration. Stare duration increased with decreasing distance to obstructive cover, which could indicate perceptual processing costs of searching for cryptic predators. We also found a significant difference in vigilance bout duration between the sexes: age was positively correlated with vigilance bout duration in males but not in females. Vigilance bout durations were longer when animals were further from escape terrain. Neither group size nor distance to other individuals was associated with stare or bout durations.