Do pronghorn (Antilocapra americana) perceive roads as a predation risk?

Abstract

The risk–disturbance hypothesis proposes that organisms respond to generalized threat stimuli; therefore, human disturbances that elicit these behaviours will cause individuals to behave similarly to avoid a natural predator. Studies have shown that pronghorn antelope, Antilocapra americana (Ord, 1815), are influenced by human disturbances. We examined several intensities of human activity and distance from disturbances as indicators of risk perception in pronghorns. We investigated whether pronghorns exhibited risk-avoidance behaviour towards road traffic consistent with the risk–disturbance hypothesis by comparing vigilance and foraging behaviour observations across increasing traffic levels and proximity to roads. Pronghorns showed higher vigilance and lower foraging times along high traffic roads during the spring season compared with lower traffic levels, suggesting that risk perception is related to traffic level. Moreover, individuals within close proximity to roads regardless of traffic level exhibited higher vigilance levels, indicating that there is an overall risk perceived towards roads. Our results also suggest that individuals in herds with young are more risk averse than other social groupings and individuals in larger groups perceive less risk. We suggest that consequences of risk-avoidance behaviour should be reflected in land-use plans that address road densities and traffic levels to better manage wildlife.